MagicQuartz 1.0x
“Phoenix”
Documentation
MATE
LABS Driving Your Passion.
About this Version’s Bird
The Phoenix is a mythological bird that is said to have the
ability to regenerate itself from its own ashes. The Phoenix
is typically described as a large, colorful bird with golden
or red feathers, and is said to have a lifespan of several
hundred years. The Phoenix is often associated with themes
of renewal, immortality, and resurrection, and has been
featured in various works of literature and art throughout
history. It remains a popular symbol today, often used to
represent personal transformation and growth.
The Phoenix was selected for this release because the devel-
opment of MagicQuartz stalled in 2016 due to time con-
straints. However, the development resumed in 2021 and
was completed in 2023. One could say that MagicQuartz
rose from its own ashes, much like the Phoenix.
Copyright 2024 Sebastian Mate
This document is subject to change without further notice.
Document revision date: February 10, 2024
AVR is a registered trademark of Microchip Technology Inc. Arduino is a
registered trademark of Arduino SRL. All other trademarks, logos and
brand names are the property of their respective owners. All company,
product and service names used in this document are for identification
purposes only.
Contents
I. Software Guide 1
1. Introduction 3
2. Features 5
3. General Information 9
3.1. Typical Application . . . . . . . . . . . . . . . . 9
3.2. Motor Compatibility . . . . . . . . . . . . . . . 10
3.3. About the Demo Version . . . . . . . . . . . . . 11
3.4. Keypad . . . . . . . . . . . . . . . . . . . . . . . 12
3.4.1. Keypad Layouts . . . . . . . . . . . . . . 12
3.4.2. Keypad Functions . . . . . . . . . . . . 12
4. Getting Started 15
4.1. Flashing the Firmware . . . . . . . . . . . . . . 15
4.1.1. Preparation . . . . . . . . . . . . . . . . 15
4.1.2. Software Installation . . . . . . . . . . 16
4.1.3. Testing the Development Board . . . . 16
4.1.4. Flashing the MagicQuartz Firmware . 17
4.1.5. Verifying the Firmware Upload . . . . 19
4.1.5.1. Blinking LED . . . . . . . . . 19
4.1.5.2. LCD Keypad Shield . . . . . . 19
4.1.5.3.
Serial Connection with GNU
Screen (Linux/macOS) . . . 20
i
4.1.5.4.
Serial Connection with PuTTY
(Windows) . . . . . . . . . . . 21
4.1.5.5. Using the Serial Connection 22
4.2. Motor Setup . . . . . . . . . . . . . . . . . . . . 23
4.2.1. Starting the Motor Setup . . . . . . . . 23
4.2.2. Motor Setup Walk-Through . . . . . . 24
4.3. Testing the Motor Setup . . . . . . . . . . . . . 29
4.4. Next Steps . . . . . . . . . . . . . . . . . . . . . 31
5. Menus and Functions 33
5.1. Main Screen . . . . . . . . . . . . . . . . . . . . 33
5.1.1. Changing the RPM or Frequency . . . 35
5.1.2. Speedbox Function . . . . . . . . . . . 35
5.2. Sensor Calibration Mode . . . . . . . . . . . . . 37
5.2.1. Overview . . . . . . . . . . . . . . . . . . 37
5.2.2. Understanding the Measurement Jitter 39
5.3. Live Quartz Mode . . . . . . . . . . . . . . . . . 40
5.3.1. Overview . . . . . . . . . . . . . . . . . . 40
5.3.2.
Understanding the Speed and Frequency
Values . . . . . . . . . . . . . . . . . . . 42
5.3.3. Speed Regulation Symbols . . . . . . . 43
5.3.4. Tuning the Speed Regulation . . . . . 45
5.4. Configuration Menu . . . . . . . . . . . . . . . 46
5.4.1. General Use . . . . . . . . . . . . . . . . 46
5.4.2. Configuration Menu Entries . . . . . . 47
5.4.2.1. Exit Menu . . . . . . . . . . . 47
5.4.2.2. Restart Inverter . . . . . . . . 47
5.4.2.3. Show Power Info . . . . . . . 48
5.4.2.4. Show Sensor Info . . . . . . . 49
5.4.2.5. Show Statistics . . . . . . . . 50
5.4.2.6. Motor Setup . . . . . . . . . . 51
5.4.2.7. Calib OvlProtThrs . . . . . . 51
ii
5.4.2.8. Format Memory . . . . . . . . 52
5.4.2.9. Shift Memory . . . . . . . . . 52
5.4.2.10. Register . . . . . . . . . . . . . 53
5.4.2.11. Set WaveForm . . . . . . . . . 54
5.4.2.12. Set PhaseShift . . . . . . . . . 55
5.4.2.13. Set DefaultHertz . . . . . . . 55
5.4.2.14.
Set VoltageMtOff / VoltageM-
tOn . . . . . . . . . . . . . . . 55
5.4.2.15. Set VoltageMtRed . . . . . . 56
5.4.2.16. Set ReducVoltage . . . . . . . 56
5.4.2.17. Set RampingTime . . . . . . 57
5.4.2.18. Set MotorRunThrs . . . . . . 57
5.4.2.19. Set OvlProtThrs . . . . . . . . 58
5.4.2.20. Set InvIdleCurr . . . . . . . . 58
5.4.2.21. Set ProtectDelay . . . . . . . 58
5.4.2.22. Set MotorSwThrs . . . . . . . 59
5.4.2.23. Set MotorSwTime . . . . . . 59
5.4.2.24. Set SensLowPass . . . . . . . 60
5.4.2.25. Set QuickCalib . . . . . . . . 60
5.4.2.26. Set MaxOKDelta . . . . . . . 60
5.4.2.27. Set BufferSize . . . . . . . . . 61
5.4.2.28. Set BufferClear . . . . . . . . 61
5.4.2.29. Set BufferWait . . . . . . . . 62
5.4.2.30. Set QrtzLatency . . . . . . . . 62
5.4.2.31. Set QuartzRange . . . . . . . 62
5.4.2.32. Set WaitOnStart . . . . . . . 63
5.4.2.33. Set WaitOnBad . . . . . . . . 63
5.4.2.34. Set BadDelta . . . . . . . . . 63
5.4.2.35. Set SaveHzAtSec . . . . . . . 64
5.4.2.36. Set StandByOff / StandByOn 64
5.4.2.37. Set TotalHours . . . . . . . . 65
5.4.2.38. Set PlayHours . . . . . . . . . 65
iii
6. Problems and Solutions 67
6.1. Related to the Motor . . . . . . . . . . . . . . . 67
6.1.1. General Motor Status Detection Fails 67
6.1.2.
Motor Status Detection upon Startup
Fails . . . . . . . . . . . . . . . . . . . . . 68
6.1.3. Generated Voltages are Wrong . . . . 69
6.1.4. Overload Detection not Working . . . 69
6.1.5. Message: “Motor turned on?” . . . . . 70
6.1.6. Message: “Motor off?” . . . . . . . . . . 70
6.2. Related to the Inverter . . . . . . . . . . . . . . 71
6.2.1. Message “Inverter fail? Turn off!” . . . 71
6.2.2. Message: “Invrt. overload! Retry?” . . 72
6.2.3. Message: “Inverter down? Retry?” . . 73
6.3. Related to the Motion Sensor . . . . . . . . . . 74
6.3.1. Not Leaving Sensor Calibration . . . . 74
6.3.2.
Dropped Speed Measurements in Live
Quartz Mode . . . . . . . . . . . . . . . 74
6.3.3. No Play Symbol in Live Quartz Mode 75
6.4. Other Problems . . . . . . . . . . . . . . . . . . 75
6.4.1. Message: “Checksum error!” . . . . . . 75
6.4.2. Message: “APM not available!” . . . . 76
6.5. Emergency Access . . . . . . . . . . . . . . . . . 77
7. Appendix 79
7.1. Graphical and Serial Symbols . . . . . . . . . . 79
7.2. Revision History . . . . . . . . . . . . . . . . . . 80
II. Theory of Operation 81
8. Signal Generation 83
8.1. Introduction to PWM . . . . . . . . . . . . . . . 83
iv
8.2. PWM Implementation in MagicQuartz . . . . 85
8.3. Wave Forms . . . . . . . . . . . . . . . . . . . . 86
8.4. Voltage Regulation . . . . . . . . . . . . . . . . 89
9. Advanced Power Management 91
10.Rotation Sensor 93
11.Flash Memory Handling 95
III. Hardware Interface 97
12.Microcontroller Configuration 99
13.Pin Utilization 101
13.1.I/O Modes . . . . . . . . . . . . . . . . . . . . . 101
13.2.Buttons . . . . . . . . . . . . . . . . . . . . . . . 103
13.3.Display . . . . . . . . . . . . . . . . . . . . . . . 103
13.4.PWM and Clock Signals . . . . . . . . . . . . . 104
13.5.Other Signals . . . . . . . . . . . . . . . . . . . . 105
14.Compatible Hardware 107
14.1.Development Boards . . . . . . . . . . . . . . . 107
14.2.LCD Keypad Shields . . . . . . . . . . . . . . . 108
v
Part I.
Software Guide
1
1. Introduction
Welcome to Precise Turntable Speed!
MagicQuartz is a microcontroller firmware for the accurate
speed control of HiFi record players with AC motor. The
highly configurable software can be used for control and
signal generation in true sine wave inverters, enabling the
implementation of precision turntable speedboxes or motor
power supplies.
MagicQuartz aims to perfect the playback speed of vinyl
records. It not only offers complete decoupling of a turntable
from mains frequency fluctuations, but also electronic switch-
ing and adjustment of the turntable’s speed. It is even possible
to have the speed continuously monitored and automatically
readjusted. MagicQuartz is also a valuable tool for the repro-
duction of shellac records, as non-standard speeds can be
easily set.
MagicQuartz has been developed for the 8-bit AVR micro-
controller family from Microchip (formerly Atmel). In the
context of rapid prototyping, the firmware can also be run di-
rectly on Arduino hardware, such as the Arduino Mega 2560
Rev3. To interact with the firmware, an LCD keypad shield
or a serial connection via the Arduino’s USB interface can be
used.
3
MagicQuartz is aimed at professional hardware developers
from the absolute high-end audio sector, as well as private
audio enthusiasts with appropriate knowledge in electronics.
A free demo version is available for evaluation and hardware
development purposes.
What initially started as a crazy idea soon turned into the
ambitious goal of developing the world’s best turntable speed
control software. The project now looks back on over a
decade of passionate research and development. I hope that
you will enjoy MagicQuartz!
Sebastian Mate (Erlangen, Germany)
4
2. Features
MagicQuartz is a feature-rich software. This section provides
an overview of its features. Note that some features may not
work with all turntables – please see section 3.2 on page 10
for details.
Smart Turntable Speed Control
□
Speedbox Function: Electronic speed switching be-
tween the standard record speeds (16, 33, 45, and 78
RPM) without having to change the speed setting on
the record player. Smooth AC frequency ramping. See
section 5.1.2 on page 35 for details.
□
Live Quartz Mode: MagicQuartz continuously mon-
itors the speed of the turntable and corrects the gen-
erated AC frequency if necessary so that the turntable
maintains the correct speed. See section 5.3 on page 40
for details.
□
High Timing Resolution: The system clock, speed mea-
surement, speed computations, and signal generation
operate on a high temporal resolution of 100 µs.
□
Intelligent Control: When larger speed changes occur,
the regulation automatically stops, for example, while
5
the start/stop functions of an automatic turntable are
in operation. In the event of a fault, such as a motor
failure, broken belt or idler wheel, the speed control
also stops automatically.
□
High Customizability: Adjust the regulation velocity,
set limits for the allowed frequency change, and fine-
tune many other parameters to suit your needs and
preferences.
□
Voltage Reduction: Optionally, the generated AC volt-
age can be reduced automatically in “Live Quartz Mode”,
which may lead to a significant reduction of motor noise
(i.e., hum caused by vibration) in some turntable mo-
tors.
□
Transpose Function: Musicians can easily change the
pitch of the playback in semitones.
True Sine Signal Generation
□
Multiple Wave Forms: MagicQuartz supports the gen-
eration of single-phase or dual-phase sine wave signals,
the latter with variable phase shift. To realize more
complex inverter designs, the single-phase sine wave
can also be output separately on two channels in the
form of a negative and positive half-wave. Optional
software pop suppression for less complex inverter de-
signs. Configurable, smooth up and down ramping of
the AC voltage.
□
HiFi-Compatible: The digital to analog signal con-
version is implemented using pulse width modulation
6
(PWM) at a carrier frequency of 31.250 kHz, which is
beyond the range of human hearing.
□
High-Resolution: The signal is based on 8-bit waveta-
bles with 128 samples for each full sine period, scaled
using floating point arithmetic and reproduced at a
variable sampling rate (variability in true 0.0001 Hz
steps). The latter is achieved by a clever programming
of the microcontroller’s hardware timers.
See section 8 on page 83 for details on the signal generation.
Advanced Power Management (APM)
□
Current Monitoring: Continuous measurement of the
inverter’s current at a sample rate of up to 5 Hz.
□
Voltage Correction: Detection of the motor switch-
ing status based on the inverter load, followed by a
correction of the generated voltage.
□
Error Handling: Detection and handling of inverter
shutdown and overload.
See section 9 on page 91 for details on the APM.
Other Features
□
Motion Sensor: Automatic motion sensor calibration
that also guides the user when positioning the sensor
on the turntable.
7
□
Keep Track: Uptime counters that also count the on-
time of the record player, which can be used to keep
track of stylus wear.
□
Little Distraction: When turned on, MagicQuartz auto-
matically continues in the mode it was last in, allowing
the user to focus on the music and not on MagicQuartz.
□
For Longevity: Advanced flash memory caching and
wear leveling to prolong the life of the microcontroller.
□
For Safety & Environment: Configurable automatic
standby timers.
High Adaptability to Hardware Designs
□
Platform: Designed for Microchip’s (formerly Atmel)
AVR 8-bit microcontroller family, readily available ver-
sion for the ATmega2560. The software may be ported
to other microcontrollers by the developer.
□
Display Support: Supports 2 lines by 16 characters
displays (HD44780 or compatible) or serial communi-
cation (using ANSI escape codes) at 57,600 baud.
□
Flexibility: Supports two different microcontroller
pinouts for display and buttons. Buttons can be in-
dividual buttons or buttons that are interconnected via
a resistor network.
□
Rapid Prototyping: Support for widespread prototyp-
ing hardware, such as the Arduino Mega 2560 Rev3,
including common peripherals (LCD keypad shields).
See part III on page 97 regarding hardware design considera-
tions.
8
3. General Information
3.1. Typical Application
MagicQuartz is a microcontroller firmware that can be used
for control and signal generation in a turntable speedbox.
Such a speedbox could be powered with a low DC voltage
from a fully isolated power supply. Usually, an inverter is inte-
grated into the speedbox to generate the alternating current
for the record player. The frequency of the AC is variable and
is used to control the speed of the turntable. The speed can
be measured, for example, via an optical sensor next to the
record player’s platter to which a paper sticker is attached:
Mains Power Supply Speedbox (running MagicQuartz)
Turntable (with AC motor)
Optical
Sensor
220V
AC
24V
DC
220V
AC
Sensor Signal
Sticker
9
Other configurations with other AC voltages, sensor types
(e.g., magnetic) or construction forms (e.g., speed controllers
built into turntables) are also conceivable (see part III on
page 97). The instructions in this document assume that
the MagicQuartz firmware has been installed on an external
speedbox, similar to the one shown above.
3.2. Motor Compatibility
MagicQuartz is based on the principle that the AC frequency
controls the speed of the turntable motor. Therefore, the
approach only works with AC motors. However, as there
are so many types, it cannot be guaranteed that a particular
model will work with all MagicQuartz features. In general,
however, the following applies:
□
The “Live Quartz Mode” (see section 5.3 on page 40)
with its small changes in AC frequency should work
fine with all synchronous and asynchronous motors.
□
If the motor relies on phase shift capacitors, greater
changes in AC frequency should be avoided to prevent
motor damage. It is then not recommended to use the
speedbox function (see section 5.1.2 on page 35), as
this changes the AC frequency in large steps. Note that
it may be possible to modify and properly drive such a
motor via a two-phase inverter configuration.
□
Due to the slip inherent in asynchronous motors, the
actual motor speed achieved may differ from the speed
calculated by MagicQuartz, especially when using the
speedbox or the transpose functions. However, it may
10
be possible to correct the speed in “Live Quartz Mode”.
With such motors, voltage reduction usually does not
work either, because the motor slows down with re-
duced voltage.
□
The hardware, in particular the inverter, must be laid
out to meet to the motor’s power requirements.
3.3. About the Demo Version
A demo version of MagicQuartz is available for evaluation
and hardware development purposes. It is fully functional,
except for the following:
□
The standby timers
StandByOn
and
StandByOff
(see
section 5.4.2.36 on page 64) cannot be disabled or set
higher than 10 and 5 minutes, respectively. While this
does not affect the playback of 45 and 78 RPM records,
playback of 33 RPM records may be interrupted by the
standby timer. Note that it is possible in any operational
mode to prevent the software from entering standby
without affecting playback by occasionally pressing a
button on the speedbox.
□
After some use of the software, MagicQuartz displays a
nag screen and kindly asks you to register the software.
The nag screen appears after the speedbox has been
turned on and after waking up from standby.
These limitations can be overcome by registering the soft-
ware. The registration process is described in section 5.4.2.10
on page 53.
11
3.4. Keypad
3.4.1. Keypad Layouts
MagicQuartz is operated via a keypad with four or five but-
tons. The layout depends on the implementation of the hard-
ware. The default layout is shown in the following figure on
the left. If MagicQuartz is running on an Arduino or compat-
ible development board, most likely an LCD keypad shield
with the layout shown on the right is used. If the firmware
is accessed via a serial connection, either the arrow keys or
the number keys 1 to 4 (preferably the ones on the left side
above the letter keys) on the computer keyboard can be used.
SEL
Default Keypad Layout LCD Keypad Shield Layout
RST
3.4.2. Keypad Functions
In general, the “Left” and “Right” buttons move the cursor
on the screen. The “Up” and “Down” buttons increase and
decrease the value under the cursor, respectively.
The “Up” and “Down” buttons also serve the following func-
tions:
12
□ OK/Yes: Accept what is shown on the screen.
□
Enter: Enter a function (such as the “Live Quartz Mode”)
or a menu entry (as in the “Configuration Menu”).
□
Clear Buffer: In some functions, such as the “Live
Quartz Mode”, “Show Power Info”, or “Show Sensor
Info”, pressing this button clears a buffer or temporary
value.
□ Cancel/No: Reject what is shown on the screen.
□
Exit: Exit a function (such as the “Live Quartz Mode”)
or a menu entry (as in the “Configuration Menu”).
Please note that when using a serial connection, no graph-
ical symbols can be shown. In some screens over a serial
connection, the icons
and
are replaced with “
U
” and “
D
”
to indicate using the “Up” and “Down” buttons, respectively.
For more symbol mappings in serial mode, please refer to
section 7.1 on page 79.
“Restart Inverter”: By pressing the “Left” and “Right” buttons
simultaneously, the “Restart Inverter” function (see section
5.4.2.2 on page 47) can be triggered. With an LCD keypad
shield, the “Select” button has to be pressed. When a serial
connection is used, the function can be triggered by entering
“Shift+R” on the keyboard.
13
4. Getting Started
4.1. Flashing the Firmware
This section describes in detail how to perform the initial
upload of the MagicQuartz firmware to an Arduino or com-
patible development board that employs the ATmega2560
microcontroller (please refer to section 14 on page 107 for
supported hardware). The same procedure applies when
performing future firmware updates. Note that any settings
within MagicQuartz are kept when you follow these instruc-
tions.
The process described below is the same on all popular op-
erating systems such as Linux, Apple macOS and Microsoft
Windows. Although a Linux system is used in the following,
the main differences when using Windows are highlighted.
4.1.1. Preparation
If you’re starting with an assembled speedbox, disconnect the
device from its power supply. Open the device and connect
the development board to the computer via its USB interface,
preferably using a galvanic USB isolator. Alternatively, you
can remove the development board from the speedbox and
15
then connect it to the computer via USB. If the speedbox
doesn’t integrate a development board, it may be possible to
flash the firmware using an ISP programmer.
4.1.2. Software Installation
The firmware is distributed in the Intel HEX format. For
flashing the firmware file, the open source software avrdude
(see:
https://www.nongnu.org/avrdude/
) can be used.
However, since using avrdude can be challenging, a good
approach is to use the official Arduino IDE to obtain the
command line parameters for avrdude.
Go to
https://www.arduino.cc/
and download and install
the Arduino IDE for your operating system. The Arduino IDE
already includes avrdude.
Note: When using Windows in combination with an Arduino-
compatible development board, such as the “MEGA 2560
PRO”, it may be necessary to install the “CH340” driver first.
Please ask the seller or manufacturer of the development
board for the driver.
4.1.3. Testing the Development Board
As a first step, it is necessary to configure the Arduino IDE
for the correct development board. Start the Arduino IDE
and select Tools => Board: ... => Arduino Mega or Mega
2560.
To check that everything works, you can flash a minimal
program that is supplied with the Arduino IDE. Open the
16
“Blink” program via File => Examples => 01.Basics =>
Blink. Click on the upload button, which is the round button
with the arrow pointing to the right (see next screenshot,
under the mouse cursor). The Arduino IDE may ask you to
select a serial port. Pick the one suggested and continue.
After the upload has succeeded, the LED on the development
board should start blinking in one-second intervals.
4.1.4. Flashing the MagicQuartz Firmware
Go to the preferences of the Arduino IDE. Check the option
“Show verbose output during: Upload”. Click on the “OK”
button to go back to the main window. Upload the previous
“Blink” program again. Notice the logging output in the lower
section of the window:
The third line (highlighted in blue in the screenshot above)
17
is the command which was used to execute avrdude. Copy
the full line into a text editor. Replace the file path pointing
to the
Blink.ino.hex
file with the file path pointing to the
downloaded MagicQuartz.hex file.
In my case, here’s what the original command looks like:
And here is it with the path pointing to the
MagicQuartz.hex
file:
Next, run the modified full command in a terminal to flash
the MagicQuartz firmware to the development board (in
Windows, use the Command Prompt, also known as
cmd.exe
):
18
The program’s output should look similar to this:
4.1.5. Verifying the Firmware Upload
4.1.5.1. Blinking LED
After the upload and whenever restarting the development
board, its LED should blink very fast for one second. This
indicates that the development board is now running the
MagicQuartz firmware.
4.1.5.2. LCD Keypad Shield
If an LCD keypad shield is connected to the development
board, you should see the firmware starting up, as in the
following picture:
19
4.1.5.3. Serial Connection with GNU Screen
(Linux/macOS)
If you’re using a bare development board without an LCD
keypad shield, you can interact with the firmware via the
serial connection over USB using the GNU Screen program.
To do this, run the following command in your terminal:
screen /dev/ttyUSB0 57600
You should then see MagicQuartz restarting (GNU Screen
may automatically trigger a reset of the development board).
Note: If GNU Screen throws an error message, such as “Cannot
exec ’/dev/ttyUSB0’: No such file or directory”, you may have
to use another TTY device. The easiest way to find out which
one it is, is to review the setting in the Arduino IDE. It’s
shown under the menu Tools => Board: ...
20
4.1.5.4. Serial Connection with PuTTY (Windows)
In Windows, the program PuTTY (
https://www.putty.or
g/
) can be used to connect to the firmware. As shown in the
following screenshot, enter the COM port, select the connec-
tion type “Serial”, and set the speed to 57600.
It is also possible to save and load the configuration, as shown
in the lower section of the screenshot. Please refer to the
PuTTY documentation for details. Please be aware that the
COM port’s number may change if multiple serial devices are
connected to the computer.
21
4.1.5.5. Using the Serial Connection
After startup, MagicQuartz will automatically ask you to setup
the motor:
Feel free to navigate yourself through the motor setup by
using the arrow keys on your keyboard (for details on the
motor setup, see section 4.2 on the facing page). After the
motor setup, you will arrive at the main screen:
To exit the GNU Screen program at any time, press “Ctrl+a”,
followed by “k” and “y”. You may need to zoom out before
you’re able to do this in case GNU Screen complains.
22
4.2. Motor Setup
Before the speedbox can be used with a turntable, it is nec-
essary to properly configure the inverter for the connected
record player. This ensures that the motor is driven with the
correct voltage (e.g. 120 or 220 V). Although all parameters
can also be determined and set manually, MagicQuartz fea-
tures a setup wizard, called “Motor Setup”, which automates
this process. Depending on whether the speedbox supports
the “Advanced Power Management” (APM, see section 9 on
page 91), the setup wizard also determines various other
configuration parameters that are required for the current
monitoring of the inverter.
If the speedbox does not feature a built-in voltmeter, please
use an energy cost meter or a true RMS multimeter to mea-
sure the generated voltage. In either case, observe the rules
for safe handling of high voltages!
4.2.1. Starting the Motor Setup
The motor setup wizard is automatically started upon the
first start of the firmware, after the flash memory has been
formatted, or after the hardware has been upgraded with
APM. In either case, MagicQuartz will display the following
message:
Motor Setup:
Press any key...
23
If you’ve previously completed or skipped this step, Magic-
Quartz will automatically go to the main screen. Don’t worry:
the motor setup can also be called from the configuration
menu. Simply open the configuration menu, select the corre-
sponding menu entry, and press the “OK” button:
Select Function:
Motor Setup
For details on how to open and use the configuration menu,
please refer to section 5.4 on page 46.
4.2.2. Motor Setup Walk-Through
MagicQuartz will now guide you through the motor setup
and ask you to do different things, such as to set configuration
parameters and to turn the motor on and off multiple times.
The steps requested depend on whether the speedbox has
APM available or not and whether MagicQuartz has been
configured previously.
In case a motor has been set up previously, MagicQuartz may
ask you if you aim to setup a new motor or not:
Setup new motor?
=No =Yes
If you have connected a new or different turntable to the
speedbox, answer this question with “Yes”. Also answer it with
“Yes”, if you had problems with the motor setup previously.
This resets the voltages to zero and thus prevents the risk of
24
passing excessive voltage to the record player. If you, however,
aim to refine the previous configuration using the same motor,
you can select “No”, which will allow you to keep or modify
the previous settings.
In the next step, MagicQuartz will ask you about the nominal
frequency (in Hertz) of the turntable:
Set DefaultHertz
0050.0000 OK
Set this to 50 Hz (as shown in the image above) or 60 Hz.
This can be achieved by using the “Left” and “Right“ buttons
to move the cursor below the digit to be changed and the
“Up” and “Down” buttons to increase or decrease the digit.
Move the cursor back to “
OK
” and press the “OK” button
to accept the value. (For a general introduction on how to
change parameters, see section 5.4.1 on page 46).
The next step is to set the desired wave form that MagicQuartz
generates:
Set WaveForm:
0002.0000 OK
Important: This value depends on the hardware of the speed-
box. Please
do not
attempt to guess the value, instead, refer
to the hardware documentation or section 8.3 on page 86.
If you’ve selected either wave form 1 or 2 in the previous
step, MagicQuartz will also ask you about the phase shift:
25
Set PhaseShift:
0000.0000 OK
Important: This changes the phase shift between channels
1 and 2. Note that the phase shift parameter may only be
changed in dual-phase inverter configurations. For single-
phase inverters, you
must
keep the value at 0. Setting other
values in single-phase configurations may damage the in-
verter. For details please see section 8.3 on page 86.
The next step is to adjust the voltage with the load turned
on (parameter
VoltageMtOn
, Voltage Motor On). For this,
MagicQuartz asks you to turn the motor on and to adjust the
voltage:
Turn motor on,
press OK button
Press OK button,
adjust voltage
The voltage is set on the following screen:
Set VoltageMtOn:
0000.1000 OK
In contrast to the previous parameters, no whole number is
to be entered here, but a floating point value between 0 and
1. The value affects the amplitude of the sine signal that is
generated by MagicQuartz and consequently the voltage that
26
is generated by the speedbox. 0 corresponds to no signal, 0.5
to half amplitude, and 1.0 to full amplitude. Since the value
1.0 produces the best signal (because the dynamic range is
fully utilized), the following steps aim at getting as close as
possible to this value.
Important: When increasing the value – as described below –
it is recommended not to set it directly to 1.0, but to increase
the decimal places step by step (e.g., 0.1, 0.2, 0.3, ...) to avoid
unexpected large changes in the generated output voltage.
Larger changes could lead to an over-voltage of the record
player or to a shutdown of the inverter. If the inverter acci-
dentally shuts down when you increase the voltage (in this
case the voltage immediately drops to zero and the inverter
may try but fail to turn back on), set the value back to 0.0
and slowly increase it again.
How to proceed depends on whether the inverter installed
in the speedbox has a level control or not:
□
If the inverter doesn’t have a level control, slowly in-
crease the parameter
VoltageMtOn
(via the decimal
places, as described above) until the voltage gener-
ated by the inverter reaches the target voltage of the
turntable (e.g. 220 V).
□
If the inverter has a level control, turn the level control
to zero. Set the
VoltageMtOn
value in MagicQuartz
to 1.0. Because the level control is turned down, no
voltage should be generated. Then very carefully turn
up the level control on the inverter until the gener-
ated voltage reaches to the target voltage of the record
player (e.g., 220 V). It may also be a good idea to
set a slightly higher voltage at the inverter (e.g. 225
27
V, while
VoltageMtOn
= 1) and then to reduce the
VoltageMtOn
value again (e.g., to 0.97) so that the
desired voltage (220 V) is accurately obtained. This
leaves some room for increasing the voltage later in
software.
If APM is not available, the process is now finished and
“Done!” is shown. If APM is available, the motor setup
continues with requesting setting
VoltageMtOff
(Volt-
age Motor Off) and automatically determining the pa-
rameters
MotorRunThrs
,
MotorSwThrs
,
OvlProtThrs
and
InvIdleCurr, as shown in the following:
Turn motor off,
press OK button
Stop platter,
press OK button
Press OK button,
adjust voltage
On the next screen, adjust the voltage (for the motor being
switched off) by slowly increasing the
VoltageMtOff
value:
Set VoltageMtOff
0000.1000 OK
MagicQuartz then automatically determines some parame-
ters:
28
MotorRunThrs=254
MotorSwThrs=203
InvIdleCurr=45
Finally, MagicQuartz asks you to turn the motor on once
more:
Turn motor on,
press OK button
OvlProtThrs=540
And the process is finished:
Done!
4.3. Testing the Motor Setup
If the motor setup was successful, the speedbox should now
work properly. Nonetheless, it is a good idea to double-check
this. This section briefly describes how to do this. In case
problems occur, please refer to section 6 on page 67. Note
29
that it may also help to execute the “Motor Setup” function
again, as described in the section above.
□
General Motor Status Detection: On the main screen,
switch the turntable motor on and off. The motor status
indicator in the lower right corner should show a flash
symbol (or an an “
R
” when using a serial connection)
whenever the motor is switched on and show nothing
when the motor is switched off. If this is not working,
please refer to section 6.1.1 on page 67.
□
Motor Status Detection upon Startup: It is possible
that the motor is already switched on when the speed-
box is starting up. Verify that MagicQuartz is able to
correctly detect this. If this is not the case, please refer
to section 6.1.2 on page 68.
□
Generated Voltages: Check that the generated supply
voltage stays close to the rated voltage (e.g., 220 V)
when the motor is switched on and off. Small voltage
fluctuations (about 5 V, depending on the inverter hard-
ware) are normal because MagicQuartz needs a very
short time to correct the voltage (about 200 ms). If
the voltages are off, please refer to section 6.1.3 on
page 69.
□
Overload Detection: Connect a load that slightly ex-
ceeds the rating of the record player and turn it on.
MagicQuartz should then display an overload warning,
as described in section 6.2.2 on page 72. If this is not
working, please refer to section 6.1.4 on page 69.
□
Inverter Shutdown Detection: MagicQuartz may be
able to detect if the inverter has shut down due to a
fault, but this depends on the hardware implementa-
30
tion. In particular, if the inverter’s idle current draw
(no AC is being generated) is very close to the current
draw when it is generating an AC with no motor load,
detection may not work. The shutdown detection can
possibly be triggered by manually switching off the in-
verter (if the hardware implementation allows this) or
by setting a too low
RampingSpeed
value which causes
the inverter to switch off. If the detection is working,
MagicQuartz should display a message warning about
the inverter having shut down, as described in section
6.2.3 on page 73.
4.4. Next Steps
The setup is now complete and the speedbox may now be
used. Nevertheless, here are a few more tips on what you
could do next:
□
Use the “Sensor Calibration Mode” (see section 5.2 on
page 37) to properly setup the motion sensor. After
this, try “Live Quartz Mode”, as described in section
5.3 on page 40.
□
If the sensor works fine, you may set
QuickCalib
to
1 to speed up entering “Live Quartz Mode” next time
(see section 5.4.2.25 on page 60).
□
If the inverter has warmed up in the meantime, the
voltages may have drifted slightly. You can correct the
voltages as described in section 5.4.2.14 on page 55.
□
Depending on the motor, reducing the operating volt-
age may significantly reduce motor noise, which is pos-
31
5. Menus and Functions
5.1. Main Screen
The main screen allows changing the core speed settings
for the connected turntable. It also acts as the entry point
to all other functions (e.g. the configuration menu and the
“Live Quartz Mode”). It is cursor-controlled: use the “Left”
and “Right” buttons to move the cursor below the digits
representing values (e.g.
33.3333
or
50.0000
) or characters
representing menus or functions (e.g. “
M
”, which enters the
configuration menu). Then use the “Up” and “Down” buttons
to change the values or to enter the menu or function.
Switch
16/33/45/78
RPM
Menu
Sensor Calibration Quartz AC Frequency
Remove Speed
Correction
Motor
Status
Physical
Turntable
Speed
Transpose Target Turntable Speed
33 T 33.3333 RPM
M CQ 50.0000 Hz
Physical Turntable Speed: Set this to match the physical
speed setting of the record player. “Physical” means the belt
or idler wheel setting on the turntable. For example, if the
33
record player is set to play at 45 RPM, also set the physical
platter speed in MagicQuartz to 45. Use the “Up” and “Down”
buttons to switch between the standard record speeds (16,
33, 45, and 78 RPM). Note that this setting also changes the
“Target Turntable Speed” to the respective speed, which in
general does not yet change the AC frequency. However, if the
speedbox was previously generating a non-nominal motor
AC frequency, it is ramped back to the nominal frequency.
Transpose: Use the “Up” and “Down” buttons to transpose
the playback in semitones.
Target Turntable Speed: Move the cursor below the desired
digit, then use the “Up” and “Down” buttons to increase
or decrease the RPM. The unit automatically calculates the
corresponding AC frequency.
Switch 16/45/45/78 RPM: This allows direct switching
between the standard record speeds. As such, it provides
access to the speedbox function as described in section 5.1.2
on the facing page. Move the cursor below “
RPM
” and use the
“Up” and “Down” buttons to switch between the speeds. It is
highly recommend to read section 5.1.2 in advance.
Motor Status: This shows if the turntable’s motor is running,
or not. A flash symbol (or an “
R
”) is displayed whenever it is
running, otherwise nothing is displayed.
Remove Speed Correction: Move the cursor below “
Hz
” and
press the “OK” button to switch back to the default AC fre-
quency (50 or 60 Hz). This deletes the current speed cor-
rection factor, if there is any. The speed correction factor is
automatically determined in “Live Quartz Mode” (see section
5.3 on page 40) and kept in the other modes, such as the
main screen.
34
AC Frequency: Move the cursor below the desired digit. Then
use the “Up” and “Down” buttons to increase or decrease
the AC frequency. The software automatically calculates the
corresponding target turntable speed.
Quartz: Enters the “Live Quartz Mode”, as described in sec-
tion 5.3 on page 40.
Sensor Calibration: Enters the “Sensor Calibration Mode”,
as described in section 5.2 on page 37.
Menu: Enters the “Configuration Menu”, as described in
section 5.4 on page 46.
5.1.1. Changing the RPM or Frequency
Move the cursor with the “Left” and “Right” buttons below
one of the digits (those of
33.3333
or
50.0000
) and use
the “Up” and “Down” buttons to increase or decrease the
value. If you change the RPM, MagicQuartz will automatically
calculate the corresponding AC frequency and vice versa. The
playback speed of the record player changes accordingly.
5.1.2. Speedbox Function
The speedbox function allows changing the playback speed of
the turntable without changing the physical speed setting on
it. This may be useful if the record player does not provide an
easy way to change the playback speed. For example, some
modern turntables require the user to move the belt to a
different pulley below the platter in order to switch between
33 and 45 RPM. With the speedbox function, this can be done
35
electronically. It may also enable playing records with speeds
that a record player normally does not support.
The general approach is:
1.
Change the physical platter speed in the upper left
corner to match the current setting of the turntable.
2.
Move the cursor below “
RPM
” in the upper right corner
and use the “Up” and “Down” buttons to directly switch
between the standard record speeds.
Important notes:
□
Using the speedbox function changes the generated
AC frequency in large steps. For example, switching to
78 RPM with a physical setting of 33 RPM raises the
AC frequency to 117 Hz (for a 50 Hz unit). This could
damage the record player’s motor – in particular, if it
relies on phase shift capacitors.
□
It is recommended that the turntable is set to a speed
that is close to the desired speed. For example, if you
want to play back a 78 RPM record, don’t use 33 RPM
as the physical platter speed, instead, use 45 RPM if the
record player supports it. This reduces the frequency
difference between the nominal frequency of the motor
(typically 50 or 60 Hz) and the frequency required to
obtain the target speed.
□
The AC frequency is a calculated value and may not
be optimal, depending on the type of the turntable
motor. This may be especially the case if the record
player is equipped with an asynchronous motor. After
electronically switching to a different speed, use the
“Live Quartz Mode” (see section 5.3 on page 40) to
precisely determine the optimal AC frequency.
36
5.2. Sensor Calibration Mode
5.2.1. Overview
In “Sensor Calibration Mode”, MagicQuartz automatically
adjusts itself to the dynamic range of the motion sensor, which
is used to determine the speed of the platter. In most cases
this works without problems. However, a properly positioned
motion sensor can improve the performance of MagicQuartz.
For this purpose – and in the unlikely event that problems
occur – the sensor calibration mode can help optimizing the
position of the motion sensor.
delta=4
Sensor Contrast Bargraph Contrast Status
Rotation Indicator Measurement Jitter Jitter Status
The Rotation Indicator in the lower left corner is used to
visualize whether MagicQuartz is able to correctly detect the
rotation of the turntable’s platter, or not. At each rotation, the
indicator should progress the next rectangle. If the detection
is erroneous, the rotation indicator jumps or skips. As a result,
it also displays erratic, sometimes high delta values (see
below).
When using an optical motion sensor, highly reflective platters
can cause such problems. In combination with an unevenly
machined platter rim, an oscillating reflection can trigger
false edges in the measurement signal. This can be circum-
37
vented by slightly tilting the sensor to prevent it from picking
up this reflection.
Sensor Contrast Bargraph and Contrast Status: The bar-
graph on top visualizes the measured sensor image contrast.
Try to increase the sensor contrast as much as possible (the
bargraph on top then becomes longer). A higher contrast
allows MagicQuartz to better detect the signal edge of the
bypassing paper sticker on the record player’s platter. You
can influence the contrast by moving the sensor closer or
further off to the spinning platter. It takes some time until
the bargraph changes, depending on the current RPM setting.
Note: It is normal that the bar’s ends sometimes can move
by three vertical lines on one or both sides.
If the contrast is good enough, a check mark (
) is displayed
on the right side next to the bar, as shown in the image above.
If otherwise a problem is detected, MagicQuartz automati-
cally displays the following recommendations:
Increase Distance: The sensor is too close to
the platter of the turntable. Increase the distance
between the sensor and the platter to improve
the contrast.
Reduce Distance: The sensor is either not con-
nected or too far away from the platter of the
record player. Connect the sensor or reduce the
distance between the sensor and the platter of
the turntable to improve the contrast.
38
Low Contrast: Check if you have attached a pa-
per sticker to the record player’s platter and if
the platter rotates. If everything is set up cor-
rectly but still does not work, it may help to use
a sticker with a different color (e.g. black instead
of white). In general, the sticker should be of a
different shade in comparison to the turntable’s
platter.
5.2.2.
Understanding the Measurement Jitter
The Measurement Jitter, as indicated by the delta value in
the second line of the display, is the deviation in centimillisec-
onds between two measurements. A centimillisecond is 100
µ
s, which is the internal timing resolution of MagicQuartz.
If the platter rotates at exactly 33.3333 RPM, a full platter
revolution takes exactly 1.8 seconds, 1,800 milliseconds, or
18,000 centimilliseconds. However, due to measurement er-
rors (signal noise, ambient light flicker, etc.), MagicQuartz
typically measures some variations, such as 18,002, 17,998,
18,000, 18,001, 17,997, and so on. For the first two measure-
ments, the delta value would be 4 (the difference between
18,002 and 17,998).
To improve the overall performance of MagicQuartz, it is
desirable to keep this jitter as low as possible. The ideal
value would be zero, which is usually never reached in the
long run. However, lower values (below 20) are acceptable
because MagicQuartz’ speed regulation algorithm is able to
deal efficiently with this type of measurement error.
When an acceptable jitter value is measured over a certain
time, MagicQuartz displays a check mark (
) right to the
39
delta value. If the jitter is too high (e.g. > 20), a cross (
) is
displayed instead.
You can try to reduce the measurement jitter by changing the
position of the optical motion sensor. Unfortunately, higher
contrast does not necessarily mean lower jitter. Moving the
sensor closer to the platter (and thus reducing contrast in
some cases) may also help. This is where some experimen-
tation is needed. Avoiding fluorescent or changing ambient
light is also a good idea.
MagicQuartz also features a software low-pass filter for the
optical motion sensor that can be set via the
SensLowPass
parameter (see section 5.4.2.24 on page 60). You can also
change the strength of the low-pass filter directly in sensor
calibration mode using the “Left” and “Right” buttons. A
higher value means stronger filtering. This reduces the signal
noise, but also reduces the edge quality of the bypassing
sticker. You can experiment with this parameter to further
improve the jitter.
5.3. Live Quartz Mode
5.3.1. Overview
MagicQuartz features the so called “Live Quartz Mode”, in
which it constantly monitors and corrects the record player’s
speed. Based on the current speed, the optimal AC frequency
is calculated and generated to correct possible speed devia-
tions.
40
To enter this mode, select the “
Q
” symbol in the bottom left
corner of the main screen and press the “OK” button. Mag-
icQuartz briefly enters the “Sensor Calibration Mode” (see
section 5.2 on page 37) before it continues into “Live Quartz
Mode”. Press the “Cancel” button to exit at any time. The
“Live Quartz Mode” screen is depicted in the following figure:
33.3333 RPM
50.0000 Hz
Ring Buffer Indicator Measured Average Turntable Speed
Rotation Indicator AC Frequency
Quartz
Strategy
The Rotation Indicator has the same functionality as in
“Quartz Calibration Mode” (see section 5.2 on page 37 for
details). It should progress to the next rectangle at each
rotation and never skip.
MagicQuartz displays the Measured Average Turntable
Speed of the turntable’s platter on top and the computed
and generated AC Frequency on the bottom of the screen.
Pressing the “OK” button clears the measured average record
player speed. Note that this does not affect the speed regu-
lation. Keeping the “OK” button pressed enters a temporary
“fast” mode with
QrtzLatency
= 1 (see section 5.3.4 on
page 45) and an “
F
” is shown in the lower right corner. This
enables MagicQuartz to quickly adopt to speed changes.
The generated AC frequency has to be higher at the beginning
of a record than at the end of a record. In order to quickly
arrive at the ideal frequency when a new record is put on,
MagicQuartz is capable of automatically storing and restoring
41
this frequency. Whenever the frequency is saved at the begin-
ning of a record, “
-SAVED-
” is displayed. When “Live Quartz
Mode” is entered, or when the motor has been switched off
and on again in “Live Quartz Mode”, “
(Speed restored)
”
is displayed, and the initial AC frequency is restored. The
time at which the frequency is saved can be configured via
the parameter
SaveHzAtSec
, as described in section 5.4.2.35
on page 64.
5.3.2. Understanding the Speed and
Frequency Values
The measured average turntable speed is an unweighted mov-
ing average of the previous speed measurements (one per
rotation). MagicQuartz calculates this speed by storing speed
measurements in a ring buffer. When this buffer is full, the
oldest values are overwritten again. The fill level and current
writing position are displayed with the Ring Buffer Indicator
in the upper left corner of the screen. The buffer size is deter-
mined by the
BufferSize
parameter, which can be changed
in the configuration menu. Depending on how the parameter
is set, the measured average speed display reacts to speed
changes more promptly (smaller values for
BufferSize
) or
less promptly (larger values for
BufferSize
). When Mag-
icQuartz decides it is necessary, the buffer is automatically
cleared (see parameter
BufferClear
). At any time in “Live
Quartz Mode”, press the “OK” button to clear the ring buffer.
If MagicQuartz is not able to keep up with the speed regu-
lation (see section 5.3.3 on the next page), or whenever it
does not make sense to average the speed measurements,
42
“
LIVE
” is displayed instead of the graphical indicator and the
currently measured speed is shown.
MagicQuartz computes the AC frequency using a weighted
moving average algorithm (the weight is the parameter
QrtzLatency
, see section 5.3.4 on page 45), which takes
into account the quality of each measurement. As a result,
the speed regulation algorithm can deal with measurement
errors efficiently. It is completely independent from the pre-
viously described “simple” average speed computation. As a
result, the measured average record player speed cannot be
used to evaluate the performance of the speed regulation al-
gorithm. This can be done with the speed regulation symbols
described in the next section.
5.3.3. Speed Regulation Symbols
MagicQuartz displays icons in the lower right corner which
can be used judge how well the speed regulation works.
Perfect Speed: MagicQuartz considers the cur-
rent speed of the turntable as equivalent to the
target speed of the record player.
The following symbols may keep appearing during normal
operation. This is perfectly fine as long as the “Perfect Speed”
symbol from above keeps appearing regularly:
A Bit Too Slow: MagicQuartz is considering the
current platter speed a bit too low and has been
up-regulating the AC frequency.
A Bit Too Fast: MagicQuartz is considering the
current platter speed a bit too high and has been
down-regulating the AC frequency.
43
Too Slow: MagicQuartz is considering the cur-
rent platter speed as too low and is constantly
up-regulating the AC frequency. If this sym-
bol does not disappear, consider reducing the
QrtzLatency
parameter (see section 5.3.4 on
the next page).
Too Fast: MagicQuartz is considering the cur-
rent platter speed as too high and is constantly
down-regulating the AC frequency. If this sym-
bol does not disappear, consider reducing the
QrtzLatency
parameter (see section 5.3.4 on
the facing page).
Paused: MagicQuartz has paused the speed reg-
ulation. This for example happens after Mag-
icQuartz has rejected bad measurements (see
next) or waits for an accelerating turntable
platter. For details, see parameter
WaitOnBad
and
WaitOnStart
(see sections 5.4.2.32 and
5.4.2.33 on page 63).
Dropped: MagicQuartz has detected and
dropped a bad measurement. This usually
happens on automatic record players when the
automatic stop function kicks in at the end of
a record. For details, see parameter
BadDelta
(see section 5.4.2.34 on page 63).
In addition, the following symbols inform about special con-
ditions:
Stopped: The speed regulation is turned off
(
QrtzLatency
= 0, see section 5.3.4 on the next
page).
44
LIM
Limit Reached: The limit of the speed regula-
tion range has been reached and MagicQuartz
has stopped regulating the AC frequency for
safety reasons. Please refer to the description
of the parameter
QuartzRange
(section 5.4.2.31
on page 62) for more information.
5.3.4. Tuning the Speed Regulation
The speed regulation can be tuned via the
QrtzLatency
parameter (see section 5.4.2.30 on page 62). This can either
be set in the configuration menu or by pressing the “Left”
and “Right” buttons in “Live Quartz Mode”.
Setting
QrtzLatency
to 0 stops the speed regulation. A value
of 1 sets the speed regulation to full strength, which allows
MagicQuartz to quickly respond to speed changes. The draw-
back is that this also causes larger AC frequency changes. In
contrast, setting QrtzLatency to higher values reduces the
strength of the speed regulation.
As explained in section 5.3.3 on page 43 for the double-arrow
symbols, the speed regulation may not be able to keep up
with the speed drift if
QrtzLatency
is set too high. Magic-
Quartz then constantly shows double up or down arrows.
If this happens, simply reduce
QrtzLatency
. It is recom-
mended to set
QrtzLatency
as high as possible to avoid
larger AC frequency changes, but low enough to let the speed
regulation algorithm properly keep up with speed changes.
The default value is 3. Values higher than 6 are typically not
recommended.
45
5.4. Configuration Menu
The configuration menu allows you to set up MagicQuartz. It
allows you to execute different functions and to set parameter
values. The configuration menu can be accessed from the
main screen by selecting the “
M
” entry in the lower left corner:
Menu
33 T 33.3333 RPM
M CQ 50.0000 Hz
Use the “Left” and “Right” buttons to move the cursor below
the “M” and press the “OK” button.
5.4.1. General Use
The configuration menu starts with the “Exit Menu” entry:
Select Function:
Exit Menu
Use the “Left” and “Right” buttons to switch between the
menu entries. Press the “OK” button to enter a function. To
exit the menu, either select the “Exit Menu” entry (as shown
above), or press the “Cancel” button in any menu position.
All entries starting with “
Set ...
”, as shown in the screen
below, change numeric configuration parameters. Within
these, use the “Left” and “Right” buttons to select a digit.
46
You can then increase or decrease the value by pressing the
“Up” and “Down” buttons. To exit the screen, move the cursor
below “OK” and press the “OK” button.
Set DefaultHertz
0050.0000 OK
5.4.2. Configuration Menu Entries
5.4.2.1. Exit Menu
Exits the configuration menu and returns to the main screen.
Note that the menu can also be exited from any other position
by pressing the “Cancel” button.
5.4.2.2. Restart Inverter
As the name suggests, this function restarts the inverter. This
is done by first reducing the voltage to zero and then increas-
ing it again. Normally, and if APM is available, MagicQuartz
will detect by itself when the inverter has shut down and
inform the user. In other cases, the inverter can be restarted
manually using the “Restart Inverter” function.
Restart Inverter
The function can also be triggered in most of the screens by
pressing the “Left” and “Right” buttons simultaneously. When
47
using an LCD keypad shield, the same can be attained by
pressing the “Select” button. When using a serial connection,
the function can be triggered by entering “Shift+R” on the
computer keyboard.
Note: If you use the function in “Live Quartz Mode”, the
QrtzLatency
value may change unintentionally, if both but-
tons are not pressed at exactly the same time.
5.4.2.3. Show Power Info
This function displays information about the inverter’s cur-
rent draw, which can be used to calculate various other con-
figuration parameters. It displays the internal measurement
of the current draw, which is displayed in the lower left corner.
This function requires APM.
Recalibration
Status
W
I= 425 d= 30
Current Draw Bargraph
Current Draw Delta
Motor
Status
The Current Draw by the inverter is shown in the lower
left corner. Note: The range is from 0 (no current is drawn)
to 1023, which is the theoretical upper value that can be
measured by the microcontroller. The true upper value may
be, depending on the hardware implementation, lower.
Switching the motor on and off should display different cur-
rent values, and the Motor Status indicator should change
accordingly (if not, you may need to calibrate the motor or
48
change
MotorSwThrs
). As in the main menu, a flash sym-
bol is shown in the lower right corner when MagicQuartz
believes that the motor is switched on.
The “Show Power Info” function also displays a temporary
Delta value, which can be zeroed by pressing the “OK” button.
The inrush current compensation behavior (see section 9
on page 91) is shown with the Recalibration Status, which
displays a “
W
” (“wait”) while waiting
MotorSwTime
, and a
“
C
” (“calibrate”) when measuring the stable current again. At
nominal motor frequency, an “
S
” (“simple”) is shown instead
to indicate that the
MotorRunThrs
value is used to determine
the motor running status.
5.4.2.4. Show Sensor Info
This function displays sensor information about the motion
sensor. This function displays the measurement value of the
optical sensor. The range is from 0 to 1023.
118 730 797
Range Bargraph Current Value
Minimum Value Current Value Maximum Value
The three numbers on the bottom display the minimum,
current and maximum values. The current value is updated
at a lower refresh rate (to be readable), so quick changes
may not be shown. It might be good idea to slowly turn the
49
platter by hand. All values can be reset by pressing the “OK”
button.
5.4.2.5. Show Statistics
This function displays various usage statistics, as explained
in the following.
On the first screen, the first line displays the total time the unit
has been switched on. The second line displays the “running”
time, which is the time the turntable motor was switched on.
The purpose of this is to keep track the wear of the record
player stylus.
Tot: 1434:13:58
Run: 1359:14:23
Pressing the “OK” button displays additional information
on the flash wear leveling. This includes the currently used
memory position and the count of memory shifts:
Mem pos: 579
Mem shifts: 31
Pressing the “OK” button again displays the number of bytes
that had been written to the flash memory since the unit has
been started up:
Memory writes:
328 bytes
50
Pressing the “OK” button once more displays the time when
the next memory shift has to take place:
Next mem shift
due in 18h
MagicQuartz automatically shifts its flash memory every 24
hours of operation to spread memory writes across the whole
memory area. For details on the flash memory handling,
please see section 11 on page 95.
5.4.2.6. Motor Setup
This function, which is described in detail in section
4.2 on page 23, is used to setup the inverter and the
turntable motor by requesting the user to set
VoltageMtOff
,
VoltageMtOn
, and automatically determining the pa-
rameters
MotorRunThrs
,
MotorSwThrs
,
OvlProtThrs
,
and
InvIdleCurr
. It also resets
VoltageMtRed
and
ReducVoltage.
5.4.2.7. Calib OvlProtThrs
This function determines the parameter
OvlProtThrs
(Over-
load Protection Threshold). While this is also done in the
“Motor Setup” function (see above), the “Calib OvlProtThrs”
function follows a different approach. It aims to determine
the maximum current that can be measured, whereas “Motor
Setup” simply picks a value that is slightly above the turntable
motor’s maximum startup current.
51
To use this function, simply connect a load that exceeds the
speedbox’ rating, such as a 60W light bulb, to the speedbox.
Note: This may blow the fuse of the speedbox.
Turn on load...
OvlProtThrs=520
Press the “OK” button to exit this function again.
5.4.2.8. Format Memory
This function formats the microcontroller’s internal flash
memory and effectively resets the firmware to “factory” de-
fault. After the setup, the “Motor Setup” has to be executed
again. Before executing this function, please make sure you
have your registration code to hand; if not, please recover it
from the “Register” function (see section 5.4.2.10 on the fac-
ing page). It is also a good idea to take note of the two clock
timers
TotalHours
and
PlayHours
(see section 5.4.2.37 on
page 65) so that these can also be restored after the reset.
5.4.2.9. Shift Memory
MagicQuartz automatically shifts the whole flash memory by
one byte every 24 hours to distribute the write operations
across the whole memory area. This function triggers the
memory shift manually and resets the timer back to 24 hours.
More information about the flash wear leveling can be found
in section 11 on page 95.
52
5.4.2.10. Register
This function allows you to register your MagicQuartz li-
cense to unlock all software features. The “Register” function
will display two hardware IDs, which are unique to your
ATmega2560 microcontroller and look similar to this:
Hardware ID 1:
1F45-EB43-E451
Hardware ID 2:
4711-FE8C
When registering via email, please send these two hardware
IDs to Sebastian Mate (MATE-LABS). You will receive a regis-
tration certificate that contains an activation code comprising
ten numbers, similar to this one:
Hardware ID: 1F45-EB43-E451 4711-FE8C
Activation Code: 144 217 163 171 10 77 199
152 0 103
Number 1: 144
Number 2: 217
Number 3: 163
Number 4: 171
Number 5: 10
...
Number 9: 0
Number 10: 103
53
In the subsequent screens, enter the numbers 1 to 10 as
illustrated in the following:
Set Number 1:
0144.0000 OK
Set Number 2:
0217.0000 OK
...
Set Number 10:
0103.0000 OK
MagicQuartz will then attempt to validate the activation
code. If this process was successful, the license is registered
afterwards. Thank you for registering!
5.4.2.11. Set WaveForm
This function is used to set the wave form that is generated
by the inverter. Please refer to section 8.3 on page 86 for
details.
Default: 0
Range: 0–3
54
5.4.2.12. Set PhaseShift
This function is used to set the optional phase shift. The
setting is only applicable when
WaveForm
is 1 or 2. Please
refer to section 8.3 on page 86 for details.
Default: 0
Range: 0–255
5.4.2.13. Set DefaultHertz
Sets the default (nominal) AC frequency. It should match the
mains frequency the turntable was built for (50 or 60 Hz).
Default: 50
Range: 40–70
5.4.2.14. Set VoltageMtOff / VoltageMtOn
The parameters
VoltageMtOff
(Voltage Motor Off ) and
VoltageMtOn
(Voltage Motor On) affect the generated output
voltages when the motor is switched on or off, respectively.
When changing one of these voltages, make sure the motor
is in the appropriate switched state (i.e., switched on if you
change
VoltageMtOn
). To avoid unexpected large changes
in the output voltage, it is advised to change the lower digits
first.
The voltage rises as the value rises. Setting the value to 1
results in the highest possible output voltage while preserving
a perfect sine wave. When the value is greater than one, the
generated sine wave is chopped off at its peaks, and humming
55
from the inverter may be audible. The generated wave form
changes to a rectangular wave at higher settings. As a result,
it is advised to keep the values below or equal to 1.
If you can’t get a sufficient output voltage even with the
values set to 1, the speedbox may not be suitable for driving
the record player model.
Range: 0–9999.9990 (it is advised not to go above 1)
5.4.2.15. Set VoltageMtRed
The parameters
VoltageMtRed
(Voltage Motor Reduced) af-
fects the voltage that is is generated in the reduced voltage
mode in “Live Quartz Mode”.
Reducing the voltage can lead to a significant reduction of
motor noise (i.e., hum caused by vibration) in some turntable
motors, but it does not work with all motors. If the record
player slows down when the voltage is reduced, this feature
is not suitable for the motor.
For the voltage to be reduced in “Live Quartz Mode”, the
parameter ReducVoltage (see below) must be set to 1.
Range: 0–9999.9990 (it is advised not to go above 1)
5.4.2.16. Set ReducVoltage
Setting this parameter to 1 enables the automatic voltage
reduction in “Live Quartz Mode”.
Default: 0
Range: 0–1
56
5.4.2.17. Set RampingTime
The
RampingTime
parameter affects how fast the voltage is
decreased and increased when the inverter is shutting down,
starting up, or restarting. The value roughly corresponds to
the up-ramping time in milliseconds and the down-ramping
time in 0.5 milliseconds.
The value should be set as low as possible for performance
reasons, but high enough to prevent the inverter from unin-
tentionally entering a protection state during start-up. The
default value was chosen quite conservatively (i.e., high) to
improve out-of-the-box hardware compatibility.
Default: 250
Range: 0–9999
5.4.2.18. Set MotorRunThrs
The
MotorRunThrs
(Motor Running Threshold) parameter
sets the motor’s current draw above which the motor is con-
sidered to be switched on upon startup. The value is also used
to detect the motor switching status at nominal AC frequency
+/– 2 Hz. With a value of 0 MagicQuartz assumes that the
motor is always switched on. Please refer to the section 9 on
page 91 for details.
Default: 310
Range: 0–1023
57
5.4.2.19. Set OvlProtThrs
The
OvlProtThrs
(Overload Protection Threshold) parame-
ter sets the motor’s current draw at which the amplifier is
supposed to be overloaded during normal operation. Please
refer to the section 9 on page 91 for details.
Default: 600
Range: 0–1023
5.4.2.20. Set InvIdleCurr
The
InvIdleCurr
(Inverter Idle Current) parameter specifies
the expected quiescent current of the inverter. It is used to
detect possible inverter shutdowns (which may happen due
to the inverter overheating and shutting down). It is also
used upon boot to detect a possible internal short-circuit of
the inverter, if the current measured is greater than twice
InvIdleCurr
. Please refer to section 9 on page 91 for details.
Default: 0
Range: 0–1023
5.4.2.21. Set ProtectDelay
The
ProtectDelay
(Protection Delay) parameter sets the
time delay after which an inverter shutdown (inverter current
less than
InvIdleCurr
) or overload (inverter current higher
than
OvlProtThrs
) is handled by the software. The delay
is calculated from the set value multiplied by 200 ms, i.e. 3
corresponds to 0.6 seconds.
58
It is recommended to set a value to the lowest possible value
that does not yet produce false error messages. At the same
time, the value should be low enough to prevent a premature
automatic restart of the inverter (which often fails depending
on the hardware design).
Default: 3
Range: 0–9999
5.4.2.22. Set MotorSwThrs
The
MotorSwThrs
(Motor Switching Threshold) parameter
sets the current draw delta that is used to determine the on
and off states of the motor. A value of 0 disables the switching
state detection and MagicQuartz assumes that the motor is
always switched on. Please refer to the section 9 on page 91
for details.
Default: 40
Range: 0–1023
5.4.2.23. Set MotorSwTime
The
MotorSwTime
(Motor Switching Time) parameter sets the
delay that is used to compensate the inrush current measure-
ment, when switching the motor on. The value is in 200 ms,
i.e. a value of 5 means 1 second. Please refer to the section
9 on page 91 for details.
Default: 5
Range: 0–255
59
5.4.2.24. Set SensLowPass
The
SensLowPass
(Sensor Low-Pass) parameter sets the value
that controls the strength of the rotation sensor’s low-pass
filter. More filtering is indicated by higher values. Please see
the section 10 on page 93 for further information.
Default: 5
Range: 0–255
Note: From version 1.02 on, the upper value is 99 when using
the left/right buttons in “Sensor Calibration Mode”. Higher
values can be set in the configuration menu.
5.4.2.25. Set QuickCalib
If set to 1, MagicQuartz performs a quicker calibration when
entering “Live Quartz Mode”. It then does not check for low
enough delta values.
Default: 0
Range: 0–1
5.4.2.26. Set MaxOKDelta
Sets the maximum delta (measurement jitter) that is accepted
by the automatic sensor calibration before entering “Live
Quartz Mode” when QuickCalib is set to 0.
Default: 20
Range: 0–255
60
5.4.2.27. Set BufferSize
The
BufferSize
parameter specifies the size of the speed
ring buffer, which is used in “Live Quartz Mode” to cal-
culate the average speed of the turntable. It is advised to
pick a multiple of two. Depending on how this parameter
is set, the observed average speed value in “Live Quartz
Mode” reacts to speed changes more promptly (smaller val-
ues for
BufferSize
) or less promptly (larger values for
BufferSize
). Please keep in mind that altering this value
has no effect on the speed regulation algorithm since the
AC frequency is determined independently of the displayed
average speed.
Default: 40
Range: 0–200
5.4.2.28. Set BufferClear
BufferClear
specifies the number of platter revolutions af-
ter which the speed buffer is cleared automatically when the
platter’s speed consistently increases or decreases. In this
way, you will receive more timely speed measurements in
the event of significant speed variations (which should not
actually occur).
Default: 8
Range: 0–255
61
5.4.2.29. Set BufferWait
BufferWait
specifies the number of platter revolutions Mag-
icQuartz waits before it starts buffering them in the ring
buffer.
Default: 2
Range: 0–255
5.4.2.30. Set QrtzLatency
The
QrtzLatency
(Quartz Latency) parameter sets the inten-
sity of the speed regulation in “Live Quartz Mode”. 0 means
“off”, 1 “full intensity”. The regulation intensity decreases
with higher values.
This is the main parameter to control the performance of the
speed regulation algorithm. Please refer to section 5.3.4 on
page 45 for an explanation on how to use this value.
Default: 3
Range: 0–255
Note: From version 1.02 on, the upper value is 99 when
using the left/right buttons in “Live Quartz Mode”. Higher
values can be set in the configuration menu.
5.4.2.31. Set QuartzRange
Sets the percentage of the maximum allowed AC frequency
change in “Live Quartz Mode”.
Default: 10
Range: 0–100
62
5.4.2.32. Set WaitOnStart
Sets the number of platter revolutions MagicQuartz waits
in “Live Quartz Mode” at start or after the motor has been
switched off and on again before starting the speed regula-
tion.
Default: 3
Range: 0–255
5.4.2.33. Set WaitOnBad
Sets the number of platter revolutions MagicQuartz waits in
“Live Quartz Mode” after it has detected a “bad” measurement
(see parameter
BadDelta
to adjust the threshold) before
starting the speed regulation. Note: Do not set this to zero.
If you do, you must set
WaitOnStart
to a value that is high
enough to compensate an accelerating platter, e.g. 3.
Default: 3
Range: 0–255
5.4.2.34. Set BadDelta
Sets the delta (measurement jitter) value above which the
measurements are being considered as “bad” in “Live Quartz
Mode”. Zero disables the rejection. Note: Do not set this to
zero. If you do, you must set
WaitOnStart
to a value that is
high enough to compensate an accelerating platter, e.g. 3.
Default: 50
Range: 0–255
63
5.4.2.35. Set SaveHzAtSec
The
SaveHzAtSec
(Save Hertz at Second) parameter sets the
time in seconds in “Live Quartz Mode” after which Magic-
Quartz saves the current AC frequency as the “starting fre-
quency”. During playback, the AC is usually reduced as needle
friction decreases. If “Live Quartz Mode” is entered at a later
time, the initial frequency can be restored automatically so
that initial speed adjustment is not required.
If the turntable is a “drifter”, meaning that it accelerates
for a long time while it warms up, it is advisable to disable
this function. This avoids the need for the speed control to
compensate for an unnecessarily large range when the record
is turned over. Zero disables this feature.
Default: 30
Range: 0–255
5.4.2.36. Set StandByOff / StandByOn
Sets the standby timer in minutes. If this time has passed,
MagicQuartz will switch into standby mode. The timer is
reset whenever a key is pressed, the motor is switched on
or off and when platter motion is detected in “Live Quartz
Mode”. Zero disables the standby function.
Defaults: 5 and 40, respectively
Range: 0–9999
64
5.4.2.37. Set TotalHours
Sets the hours of the total uptime. This can be used to restore
the time counter after a unit reset. Note: It is not possible to
change minutes or seconds.
Range: 0–9999
5.4.2.38. Set PlayHours
Sets the hours of the time in which the record player’s motor
was supposed to be running. This can be used to restore the
time counter after a unit reset. Note: It is not possible to
change minutes or seconds.
Range: 0–9999
65
6.
Problems and Solutions
This section covers problems that you may encounter, along
with solutions.
6.1. Related to the Motor
Note: Running the “Motor Setup” function again, as described
in section 4.2 on page 23, may resolve any of the motor-
related problems described below.
6.1.1. General Motor Status Detection Fails
Problem: The motor status indicator in the lower right corner
does not change when the turntable motor is switched on
and off.
Solution: Try to manually decrease
MotorSwThrs
(Motor
Switching Threshold) in the configuration menu (see section
5.4.2.22 on page 59).
Problem: The motor status indicator in the lower right corner
blinks or behaves erratically.
Solution: Try to manually increase the value
MotorSwThrs
(see section 5.4.2.22 on page 59).
67
Problem: The motor status indicator disappears immediately
after the motor has been switched on.
Solution: MagicQuartz probably interprets a dropping in-
rush current peak (see section 9 on page 91) as the motor
switching off. Try to increase the value
MotorSwTime
(Motor
Switching Time) to prolong the inrush current compensation
time (see section 5.4.2.23 on page 59).
You may also use the function “Show Power Info” to deter-
mine the value
MotorSwTime
. Immediately after switching
the motor on, the current peaks for a very short time and
then normalizes to a stable current. Depending on the record
player, this can be seen in the graphical read-out of function
“Show Power Info”. The recalibration status should display
“
W
” until the peak is fully gone. If it displays “
C
” during the
current spike, you should increase the
MotorSwTime
value.
This increases the time between the “
W
” and the “
C
”. Please
refer to section 9 for more details.
6.1.2. Motor Status Detection upon Startup
Fails
Problem: MagicQuartz fails to detect the correct motor status
upon startup of the speedbox.
Solution: If MagicQuartz mistakenly recognizes that the mo-
tor is off, try to decrease
MotorRunThrs
(Motor Running
Threshold). If MagicQuartz falsely detects that the motor is
on, try to increase MotorRunThrs.
You can also use the function “Show Power Info” (section
5.4.2.3 on page 48) to manually determine the threshold
68
parameter
MotorRunThrs
, above which the motor is sup-
posed to be running. You can calculate
MotorRunThrs
with
(I
MotorOn
+ I
MotorOff
) / 2.
As a last resort, you may set
MotorRunThrs
to 0. This causes
MagicQuartz to recognize that the motor is always switched
on.
6.1.3. Generated Voltages are Wrong
Problem: The generated voltages are not correct.
Solution: Correct the voltages by adjusting the parameters
VoltageMtOff
and
VoltageMtOn
, as described in section
5.4.2.14 on page 55. Please note that the voltage readings
are only correct at the nominal frequency (as set with the
DefaultHertz
parameter). For higher frequencies, the volt-
age can be slightly higher and decreases for lower frequencies
due to the U/f characteristic (see section 8.4 on page 89).
6.1.4. Overload Detection not Working
Problem: After connecting a load that exceeds the rating
of the turntable, MagicQuartz does not display an overload
warning.
Solution:
□
Run the “Motor Setup” function again, as described in
section 4.2 on page 23.
□
Execute the function “Calib OvlProtThrs” (Calibrate
Overload Protection Threshold, see section 5.4.2.7 on
page 51).
69
6.1.5. Message: “Motor turned on?”
Motor turned on?
=No =Yes
Problem: MagicQuartz believes that the record player’s mo-
tor is switched off and therefore does not enter the “Sensor
Calibration” or “Live Quartz Mode”.
Solution:
□
Try switching the motor off and on again. If this does
not work, the current AC frequency might be too low to
allow MagicQuartz to properly detect the motor status.
□
If you’re certain that the motor is switched on, you may
press the “OK” button. Be careful as this increases the
voltage as specified by the
VoltageMtOn
parameter.
To abort and to go back to the main menu, press the
“Cancel” button.
□
If the problem persists, check the solutions in section
6.1.1 on page 67 and section 6.1.2 on page 68.
6.1.6. Message: “Motor off?”
Motor off?
=No =Yes
Problem: MagicQuartz believes that the turntable’s motor
is switched on and therefore does not allow changing the
parameter VoltageMtOff in the configuration menu.
70
Solution:
□
Try switching the motor on and off again. If this does
not work, the current AC frequency might be too low to
allow MagicQuartz to properly detect the motor status.
□
If you’re certain that the motor is switched off, you may
press the “OK” button.
□
If the problem persists, check the solutions in section
6.1.1 on page 67 and section 6.1.2 on page 68.
6.2. Related to the Inverter
6.2.1. Message “Inverter fail? Turn off!”
Inverter fail?
Turn off! I=70
Problem: The inverter, while in idle mode (i.e., no signal is
currently sent to the inverter), is drawing more than twice
the current as specified in the parameter
InvIdleCurr
. It
is recommended to turn the speedbox off to avoid possible
damage.
Solution: If the shown
InvIdleCurr
value is rather high,
this may be due to a short circuit in the inverter. In this case,
you may need to replace the inverter.
If the value shown is rather low and the motor is currently
running, turn the motor off. Run the “Motor Setup” function
again as described in section 4.2 on page 23.
71
If the motor is not running, switch the speedbox off and on
again while keeping the “OK” button pressed. This disables
APM and allows you to increase the value
InvIdleCurr
manually. Set this to a value slightly higher than the I value
in the error message and restart restart the speedbox.
6.2.2. Message: “Invrt. overload! Retry?”
Invrt. overload!
I=600 Retry?
Problem: This happens when the inverter is drawing more
current than allowed by the parameter
OvlProtThrs
. If the
error occurred directly after the “Motor Setup”, it is very likely
that you forgot to switch the motor on again in the last step.
Solutions:
□
Press the “OK” button to retry. MagicQuartz then at-
tempts to restart the inverter. If this does not work and
the message appears again, press the “Cancel” button
to temporarily disable the output signal generation.
□
If the problem persists, run the “Motor Setup” function
as described in section 4.2 on page 23.
□
Use the function “Calib OvlProtThrs” as described in
section 5.4.2.7 on page 51.
□
Increase the
OvlProtThrs
value or increase the value
ProtDelay (see section 5.4.2.21 on page 58).
72
6.2.3. Message: “Inverter down? Retry?”
Inverter down?
I=13 Retry?
Problem: This happens when the inverter is drawing less
current than specified by the parameter InvIdleCurr.
Reason: The inverter has switched itself off or into protection
mode because the load was too high or MagicQuartz was too
fast when ramping up the voltage. This is a common problem
with sensitive inverters.
Solution:
□
Press the “OK” button to retry. MagicQuartz then at-
tempts to restart the inverter. If this does not work and
the message appears again, press the “Cancel” button
to temporarily disable the output signal generation.
□
If the problem persists, run the “Motor Setup” function
as described in section 4.2 on page 23.
□
Increase the
RampingTime
value, as described in sec-
tion 5.4.2.17 on page 57.
□
If the problem still persists, decrease the value
InvIdleCurr
or increase the value
ProtDelay
(see
section 5.4.2.21 on page 58).
Reason: The inverter has switched itself off because it was
running too hot.
Solution:
□ Wait some time, then press the “OK” button to retry.
□ Try to improve the cooling of the inverter.
73
6.3. Related to the Motion Sensor
Note: If there are problems with the speed measurement,
check that the record player is in good mechanical condition.
For example, a slipping belt or a belt rubbing against the
edge of the motor pulley may cause problems similar to those
described below.
6.3.1. Not Leaving Sensor Calibration
Problem: When attempting to enter “Live Quartz Mode”,
MagicQuartz never leaves the sensor calibration screen. The
sensor contrast and/or jitter are not considered good enough
by MagicQuartz to continue.
Solution:
□
Please refer to section 5.2 on how to properly setup
the sensor.
□
If the jitter is still a problem, you may try to increase
the parameter
MaxOKDelta
. If nothing else helps, you
can also set
QuickCalib
to 1. Depending on how “bad”
the jitter is, the speed regulation in “Live Quartz Mode”
may not work satisfactory.
6.3.2. Dropped Speed Measurements in Live
Quartz Mode
Problem: MagicQuartz constantly drops bad measurements
(the symbol
is shown in the lower right corner), pauses the
74
speed regulation (symbol:
) and never (or rarely) displays
the “Play” symbol (
). The reason is that the jitter is too high.
Solution: Please refer to the solution of the problem above.
6.3.3. No Play Symbol in Live Quartz Mode
Problem: MagicQuartz constantly displays double up or
down arrow symbols (
and
) and never (or rarely) dis-
plays the “Play” symbol (
). The speed regulation algorithm
can’t keep up with the speed changes of the turntable.
Solution:
QrtzLatency
is set too high. Reduce
QrtzLatency
to a value >= 1 by pressing the “Left” and “Right” but-
tons in “Live Quartz Mode”. Note: It is not possible to set
QrtzLatency
to less than 1 (0 turns the speed regulation
off).
6.4. Other Problems
6.4.1. Message: “Checksum error!”
Checksum error!
=Halt =Ignore
Problem: MagicQuartz has detected a problem with the data
integrity of the microcontroller’s flash memory. The most
likely reason is that the speedbox was turned off while it was
saving data.
75
Solution: Since often only the values of the time counters
(
PlayHours
and
TotalHours
as well as the minute counters
that are not accessible to the user) have changed between the
individual memory write operation, the use of the speedbox
can in most cases continued by pressing the “OK” button.
Note, however, that this will reset some more critical run-
time values (e.g. the frequency and platter speed) to their
default values for safety. The
PlayHours
and
TotalHours
parameters should also be checked in the configuration menu
afterwards. If the error message occurs more frequently, the
memory of the microcontroller could be defective.
6.4.2. Message: “APM not available!”
APM not
available!
Problem: The hardware MagicQuartz is running on appar-
ently does not support the Advanced Power Management
(APM, see section 9 on page 91).
Solution: This is the expected behavior with Arduino and
compatible development boards. However, if the device sup-
ports APM, check if the hardware is properly configured for
it, e.g. via a jumper or a microswitch on the board. You can
also check if the signal “Enable APM” is pulled to ground, as
described in section 13.5 on page 105.
76
6.5. Emergency Access
In case of a misconfiguration of the software, it may no longer
be possible to start the device correctly, which could result
in the inability to correct the configuration. In order to over-
come this problem, emergency access to important functions
is made available during startup. To access these functions,
press and hold the respective button when MagicQuartz
shows the startup screen:
□
Left Button: Calls the “Format Memory” function as
described in section 5.4.2.8 on page 52.
□
Right Button: Calls the “Motor Setup” function as de-
scribed in section 4.2 on page 23.
□
Down Button: Disables the output signal, thereby effec-
tively switching the inverter off. During operation, the
signal can be reactivated at any time via the “Restart
Inverter” function, as described in section 5.4.2.2 on
page 47.
□
Up Button: Disables the Advanced Power Management
(APM) in software. For an introduction to APM, see
section 9 on page 91.
Please note that the emergency access is not available when
using a serial connection.
77
7. Appendix
7.1. Graphical and Serial Symbols
When using a serial connection, no graphical symbols can be
displayed, so these are replaced by text symbols.
General Symbols
Graphical:
Serial: U D R
Symbols in “Sensor Calibration Mode”
Graphical:
Serial: + - C *
Symbols in “Live Quartz Mode”
Graphical:
Serial: | ) ( > < W D S
79
7.2. Revision History
Note: This history covers major and minor revisions (first and
second digits), but not patches (third digit). For full details,
please refer to the detailed MagicQuartz change log available
on the website.
Version 0.9 (May 7, 2015)
□ First version for the ATmega328P microcontroller.
Version 1.0 “Phoenix” (April 1, 2023)
□
Ported to the ATmega2560 microcontroller. A single
firmware binary now supports different hardware con-
figurations, as described in section 13.1 on page 101.
□
Many parts of the previous version fully reimplemented
(“Motor Setup”, APM motor status detection) or im-
proved (“Live Quartz Mode”, APM handling of inverter
errors, flash memory handling, emergency access).
□
New features: Voltage reduction in “Live Quartz Mode”,
function to restart the inverter, license registration.
□
Signal generation: Improved wavetables, new sine
waves (
WaveForm
= 1 and 2), optional phase shift,
and smooth voltage and frequency ramping.
80
Part II.
Theory of Operation
81
8. Signal Generation
8.1. Introduction to PWM
MagicQuartz uses a technique called pulse width modulation
(PWM) to generate sinusoidal signals. PWM is a common
technique for generating analogue signals from digital sys-
tems and works by rapidly switching a digital signal between
its high and low states at a fixed carrier frequency.
In PWM, the amount of time the digital signal remains in
its high state, also known as the on-time or duty cycle, de-
termines the corresponding analogue signal level. The duty
cycle is expressed as a percentage of the total period, where
100% means the digital signal stays high all the time and 0%
means it stays low all the time.
For example, if the digital signal has a maximum value of 5 V
and the duty cycle is set to 50%, the digital signal will be high
half the time and low half the time. As a result, the analogue
signal will be at 2.5 V, which is half the maximum value. This
is because the duty cycle defines the proportion of the time
that the digital signal is in its high state, and therefore the
proportion of the maximum value that the analogue signal
represents.
83
0% Duty Cycle 50% Duty Cycle 100% Duty Cycle
However, the resulting PWM signal by nature contains high
frequency components that are undesirable in many applica-
tions, such as audio or power control. To remove these high
frequency components, a low pass filter is typically used to
filter the PWM signal, resulting in a smooth and more stable
analogue signal.
The following figure illustrates the relationship between a
sinusoidal signal (top) and the corresponding PWM signal
(center). The PWM signal is simplified in the sense that the
duty cycle is not shown as rising and falling.
PWM Signal
(simplified)
Combined
Sine Wave
84
8.2. PWM Implementation in
MagicQuartz
In some applications, such as an inverter driving a record
player, the PWM carrier frequency can be audible in the re-
sulting audio signal, causing unwanted noise or interference.
To prevent this, MagicQuartz uses a PWM carrier frequency of
31.250 kHz, which is outside of the range of human hearing.
The generated signal is fed into the inverter, which then
generates the high-voltage AC (i.e., 120 or 220 V). At full
amplitude, a dynamic resolution of 8 bits (
WaveForm
1 and
2) or 9 bits (
WaveForm
3) with 128 discrete values (samples)
per period is achieved.
Since the AC signal is reproduced at a variable sampling rate,
all 128 samples of the wavetable are replayed at each AC
frequency to be generated, which results in an undistorted,
pure sinusoidal signal. However, since the internal timing of
the microprocessor limits the variability of the playback sam-
pling rate, it was necessary to develop a special technology,
which allows finely graduated frequency changes in steps of
only 0.0001 Hz. This is achieved by a clever programming
of the microcontroller’s hardware timers.
85
8.3. Wave Forms
MagicQuartz is capable of generating three different types
of wave forms that can be set via the WaveForm parameter:
□
0: Disabled. This disables the signal generation. This
value is set by default to prevent possible damage to
the inverter or the connected turntable.
□
1: Single or dual phase full sine wave with fixed 2.5
V DC offset. Use this if the speedbox uses an analog
interface to the inverter and features hardware-based
pop-suppression. The generated sine is referenced to
a 2.5 V offset. Since this offset is enabled shortly after
switching on, this may generate a voltage pulse (“pop”)
in the inverter. The “DAC Active” signal (see section
13.5 on page 105) can be used to implement means on
the hardware side to prevent this pulse.
□
2: Single or dual phase full sine wave with dynamic
DC offset and software-side pop-suppression. Use
this if the speedbox uses an analog interface to the
inverter and does not implement hardware-based pop-
suppression.
□
3: Single phase half sine wave. Use this if the speed-
box uses a digital interface to the inverter.
The phase shift results from the offset in samples between the
first and second channel during signal reproduction. Because
the wave is stored in 128 samples, a
PhaseShift
value of
0 corresponds to 0°, 32 to 90°, 64 to 180°, and so on. For
WaveForm
= 3 it is not possible to set a phase shift because
the two channels are used to reproduce the two halves of the
sine wave.
86
PhaseShift = 0
(0°)
PhaseShift = 32
(90°)
PhaseShift = 64
(180°)
WaveForm 1 and 2 (low-pass filtered, idealized)
Volts
5
2.5
0
Time
Volts
5
2.5
0
Time
Volts
5
2.5
0
Time
WaveForm 3 (low-pass filtered, idealized)
Volts
5
2.5
0
Time
Volts
5
2.5
0
Time
Channel 1
Channel 2
87
The following figure illustrates the difference between
WaveForm
1 and 2 in longer-term operation (“R.D.” = “Ramp-
ing Down”). The dashed areas are to be understood as the
envelope of the sine signal. As can be seen in the upper sec-
tion on the left,
WaveForm
1 may produce a pop as soon as the
generated voltage is brought to the 2.5 V offset (which is the
zero level of the sine wave). This is avoided with
WaveForm
2
by using a dynamic DC offset (the dynamic DC offset results
from half voltage of the envelope).
Volts
5
2.5
0
Time
WaveForm = 1 (DC coupling, idealized)
| Ramping Up | Normal Operation | R.D. | Standby | Ramping Up
DC Offset and Long-Term Operation
Volts
5
2.5
0
Time
WaveForm = 2 + 3 (DC coupling, idealized)
| Ramping Up | Normal Operation | R.D. | Standby | Ramping Up
Pop
All signals generated by the microcontroller are DC signals
for technical reasons. Since the signals of
WaveForm
1 and 2
are typically brought to the inverter via an analog interface,
they may have to be AC-coupled. With
WaveForm
2, however,
this has the disadvantage that drift effects may occur due to
the dynamic offset of
WaveForm
2. This is of little relevance
in practice.
88
8.4. Voltage Regulation
Depending on the detected motor status (“on” or “off”), the
factors
VoltageMtOn
or
VoltageMtOff
are applied to the
amplitude of the generated signal in order to adjust the supply
voltage. Both values should be set to output exactly the rated
voltage of the record player (220 or 120 V) at the rated
frequency (as set in DefaultHertz).
MagicQuartz implements a simplified volts-per-frequency
(V/f) characteristic. It is simplified in that, although the volt-
age decreases linearly with decreasing frequency, it does not
increase when the generated frequency exceeds the rated
frequency of the motor. This is done for safety reasons and to
avoid damaging other electronic components in the turntable.
The voltage correction factor results from the ratio of the
generated frequency and the rated frequency. For example,
a 220 V / 50 Hz turntable motor, when running at 25 Hz, is
driven with 110 V. At 60 Hz, however, the voltage remains at
220 V:
Volts
Hertz
50
220
110
25 60
89
9. Advanced Power
Management
An optional feature called “Advanced Power Management”
(APM), which is able to constantly monitor the inverter cur-
rent, can be used to automatically detect the motor status
and to intercept possible inverter fault conditions.
Current
Time
OvlProtThrs
MotorRunThrs
InvIdleCurr
(2) Signal on
Inrush current peaks
Motor off Motor on off on
2 * InvIdleCurr
(3)
(4b)
(4a)
(1)
(5) (5) (5)
(6) Wait MotorSwTime
After switching the device on (1), the current (I) drawn by
the inverter is measured before signal generation is activated.
If I > 2 *
InvIdleCurr
(Inverter Idle Current), MagicQuartz
displays the warning “Inverter fail? Turn off!”.
MagicQuartz then activates the signal generation (2). It is
possible that the turntable motor has already been switched
on before the speedbox. If I >
MotorRunThrs
(Motor Running
Threshold), MagicQuartz assumes that the motor was already
91
turned on (3). In the figure, this is not the case, so the motor
is assumed to be off.
From now on, MagicQuartz continuously monitors the cur-
rent of the inverter to check if it is overloaded or in shutdown
mode:
□
I >
OvlProtThrs
(4a): Triggers an overload warning,
as described in section 6.2.2 on page 72.
□
I <
InvIdleCurr
(4b): Triggers an inverter shutdown
warning as described in section 6.2.3 on page 73.
MagicQuartz also continuously detects if the motor switches
on or off. In the figure above, this happens three times (5).
The way the detection works depends on whether the mo-
tor is currently running at nominal frequency (parameter
DefaultHertz
) or not. At nominal motor frequency (+/– 2
Hz), the
MotorRunThrs
value is used to determine the motor
switching status, as described above. Since this approach is
unreliable at other frequencies, MagicQuartz uses a relative
current value (d) to detect switching events. The detection
sensitivity is specified via the
MotorSwThrs
(Motor Switching
Threshold) parameter and works as follows:
□ d > MotorSwThrs: Motor has been switched on.
□ d < –MotorSwThrs: Motor has been switched off.
Whenever MagicQuartz has detected a switching event, it
waits the time specified in
MotorSwTime
(Motor Switching
Time) to ignore possible inrush currents (6).
92
10. Rotation Sensor
The rotation sensor signal is used to determine the speed of
the record player’s platter. Typically, an optical sensor is used
in combination with a paper sticker that is attached to the
turntable’s platter.
The original sensor signal is typically overlaid with a noise
signal, which can cause falsely detected edges, as shown in
the following figure (circle):
Time
Maximum
Minimum
Switching
Threshold
By applying a low pass filter, this noise can be removed.
The higher the strength of low pass filter, the more noise
is removed. However, the filter also smoothens the overall
signal, turning it from a rectangular-like signal (as shown
above) into a more sine-like signal (as shown below). This
also reduces the quality of the edges and reduces the precision
of the edge detection.
93
Time
Maximum
Switching
Threshold
Minimum
In MagicQuartz, such a low-pass filter can be configured by
changing the parameter
SensLowPass
, where higher values
mean more filtering.
The graphical display in the function “Show Sensor Info” can
be used to evaluate how well the rotation signal is suited
to be processed by MagicQuartz. For an optimal signal, the
current sensor value (black box) flips between maximum
and minimum. In case an optical sensor and a paper sticker
attached to the platter is used, the bypassing sticker causes the
short “low” periods. MagicQuartz is interpreting flips across
the half of the detected range (dashed area), i.e. (Maximum
+ Minimum) / 2 as detected edges (switch threshold).
Please note that for real-world signals, the current value typ-
ically does not always flip between minimum and maximum
due to the noise added to the signal (see above). This is
perfectly fine as long as the “high” and “low” periods are well
above and below the switching threshold.
However, if e.g. the maximum value (which in our above
example is the rim of the platter and not the sticker) is not
stable and goes below the switching threshold, MagicQuartz
will fail to detect a “sharp” edge in the optical signal. It will
detect an edge before the sticker reaches the optical sensor.
This may happen if the rim of the record player’s platter does
not have a constant brightness, as e.g. on polished platters.
94
11. Flash Memory
Handling
MagicQuartz implements a comprehensive abstraction layer
for the internal flash memory of the microcontroller with the
aim of reducing the number of write operations to individual
memory cells. It should be noted that the life expectancy of
the microcontroller flash memory is by no means low, and to
date there has been no experience with any memory failure.
The techniques described below had been implemented solely
with the aim of creating a long-lasting product:
□
If data are to be stored, the memory cells are first read
and only updated if the values differ.
□
The firmware uses delayed writing operations. For ex-
ample, when the user changes parameters on the main
screen or in the menus, the data are not saved until
the user has stopped entering anything or using the
speedbox for 10 seconds.
□
Similarly, runtime statistics are only saved every 5 min-
utes. To compensate for the fact that in average 2.5
minutes are “lost” when turning the device off, the
firmware automatically adds 2.5 minutes upon startup.
□
The data to be stored in flash memory require only
a tiny fraction of the available space. To reduce the
95
write operations to individual memory cells, the data
are shifted by one byte every 24 hours when the device
enters standby mode. The initial memory position is
determined randomly when the firmware is started
the first time or after formatting the memory. If the
device has not entered standby mode for 48 hours, the
memory shift will occur the next time the device is
powered up.
□
The data integrity of the flash memory is tracked via a
checksum.
□
Each time data are written to the memory, an LED
lights up briefly, depending on the hardware design
(see section 13.5 on page 105).
96
Part III.
Hardware Interface
97
12. Microcontroller
Configuration
The microcontroller must be operated with a 16 MHz clock.
To increase accuracy, a quartz crystal should be used instead
of a ceramic resonator. Note that the Arduino and compatible
development boards usually employ a ceramic resonator. See
section 14.1 on page 107 for details.
The fuse bytes should be configured as follows:
□ Low Fuse: FF
□ High Fuse: D8
□ Extended Fuse: FD
If these have not yet been changed manually, they should
be configured this way on any new Arduino or compatible
development board.
99
13. Pin Utilization
This section describes the functions of all microcontroller pins
used by MagicQuartz. In the following, the mentioned pins
refer to the ATmega2560 microcontroller. The corresponding
Arduino pins are given in brackets. For example, “PF0 (A0)”
refers to the ATmega2560 pin “PF0” and Arduino pin “A0”.
The following documentation does not describe the common
ATmega2560-related circuit sections, such as the power sup-
ply, reset line, connection of the crystal oscillator, serial port
and others. Please refer to the official documentation from
Microchip. The schematics of Arduino boards are also a good
starting point for own developments.
Important: For all electrical parameters of the ATmega2560
microcontroller, which is also used on the compatible devel-
opment boards, please refer to Microchip’s official documen-
tation. Note that the ATmega2560 is a 5 V microcontroller
and for input signals, the voltage must not exceed 5 V.
13.1. I/O Modes
MagicQuartz was developed with the goal of high adapt-
ability to different hardware designs. For this reason, the
101
firmware (in the form of a single binary that is flashed to the
microcontroller) supports three different I/O modes:
□
I/O Mode 1 (Default): The pin use of the microcon-
troller has been optimized for the “MEGA 2560 PRO”
board. By using only the outer pins of the board, it can
be easily integrated into own hardware designs (e.g.,
as daughterboard) or used on a breadboard.
□
I/O Mode 2 (LCD keypad shield): The pin use of
the microcontroller has been optimized to support the
typical LCD keypad shields on an Arduino board (such
as the Arduino Mega 2560 Rev3) while ensuring that
the LCD keypad shield does not block or cover the other
required pins.
□
I/O Mode 3 (Serial): There are no buttons or a display.
A serial communication at 57,600 baud with ANSI es-
cape codes is used to interface with MagicQuartz. This
allows executing the MagicQuartz firmware directly
on an Arduino board (such as the Arduino Mega 2560
Rev3) without any additional hardware required. Us-
ing the serial mode is described in section 4.1.5 on
page 19.
MagicQuartz detects the mode by itself upon startup based
on the following conditions:
□ If PA3 (D25) is pulled to ground: I/O Mode 1
□ If PF0 (A0) > 2.5 V: I/O Mode 2
□ If none of the above apply: I/O Mode 3
102
13.2. Buttons
In I/O Mode 1, the buttons should be connected so that they
pull the corresponding pin of the microcontroller to ground
when pressed.
In I/O Mode 2, an analog voltage is measured via the ADC.
The voltage can be generated in the circuit, for example, via
a resistor network (please refer to the schematic of a typical
LCD keypad shield for an example).
All buttons are debounced in software.
Button Direction I/O Mode 1 I/O Mode 2
Left Input PA1 (D23) PF0 (A0) < 0.25 V
Right Input PD0 (D21) PF0 (A0) < 0.95 V
Down Input PD2 (D19) PF0 (A0) < 1.86 V
Up Input PH0 (D17) PF0 (A0) < 2.70 V
Select Input n/a PF0 (A0) < 3.86 V
13.3. Display
MagicQuartz can drive a 2 lines by 16 character display that
uses an HD44780 or compatible controller (e.g., KS0070,
ST7066U) in 4 bit mode, which only uses the DB4-DB7 data
lines. The lower data lines of the display are to be left open.
Please refer to the data sheet of the display regarding contrast
control and backlight.
103
Display Direction I/O Mode 1 I/O Mode 2
DB7 (Pin 14) Output PJ0 (D15) PH4 (D7)
DB6 (Pin 13) Output PB5 (D11) PH3 (D6)
DB5 (Pin 12) Output PH6 (D9) PE3 (D5)
DB4 (Pin 11) Output PH4 (D7) PG5 (D4)
E (Pin 6) Output PE3 (D5) PH6 (D9)
R/S (Pin 4) Output PE5 (D3) PH4 (D8)
13.4. PWM and Clock Signals
Signal Direction Any I/O Mode
PWM Channel 1 Output PL3 (D46)
PWM Channel 2 Output PL5 (D44)
50 Hz Reference Output PG1 (D40)
Regulated Frequency Output PL7 (D42)
(Reserved) Output PD7 (D38)
The PWM channels 1 and 2 are used to generate the sine
waves used to drive the inverter as described in 8.3 on page 86.
The “50 Hz Reference” signal is a rectangular fixed 50 Hz
reference signal. The “Regulated Frequency” signal is a rect-
angular signal with the same frequency as the regulated
target frequency (as for PWM channels 1 and 2).
104
13.5. Other Signals
Signal Direction Any I/O Mode
Platter Rotation Sensor Input PF4 (A4)
Enable APM Input PA5 (D27)
APM Current Sense Input PF2 (A2)
Enable I/O Mode 1 Input PA3 (D25)
LED Output PB7 (D13)
Not in Standby Output PB4 (D10)
DAC Active Output PC1 (D36)
The “Platter Rotation Sensor” input expects an analog voltage
between 0-5 V and can be used to measure the rotational
speed of the turntable’s platter, as described in section 10 on
page 93.
“Enable APM”, when pulled to ground, enables the “Advanced
Power Management” (APM) feature. The “APM Current Sense”
input expects an analog voltage between 0–5 V and is used
to measure the current draw of the inverter. Please refer to
section 9 on page 91 and section 8.4 on page 89 for details.
“Enable I/O Mode 1”, when pulled to ground, enables the
I/O Mode 1 (see section 13.1 on page 101).
The “LED” signal is high to turn an LED on. It is used to
rapidly flash the default Arduino LED upon startup to indicate
that the MagicQuartz firmware has been flashed successfully
(see section 4.1.5 on page 19 for details). During normal
operation, it will also turn high when data is written to the
flash memory of the microcontroller, as described in section
4.1.5 on page 19.
105
The “Not in Standby” signal is high during normal operation
and low when MagicQuartz is in standby mode. This signal
can be used to turn the LCD backlight on and off.
The “DAC Active” signal is high 100 ms before MagicQuartz
starts generating the sine signals for the inverter (PWM chan-
nels 1 and 2) and is low 100 ms after it has stopped generating
these signals. The “DAC Active” signal can be used in more
complex inverter designs to mute or completely disable the
inverter and implement hardware-based pop suppression.
106
14. Compatible Hardware
14.1. Development Boards
MagicQuartz should work fine with any ATmega2560-based
development board. I have successfully tested the Arduino
Mega 2560 Rev3, the ELEGOO Mega-R3, and another older,
unbranded clone. These boards are great for prototyping
when used in combination with an LCD keypad shield (see
below). However, as they use ceramic resonators to generate
the clock signal, they typically provide less timing accuracy.
In contrast, the Mega 2560 PRO (Embed), while it cannot
be used with an LCD keypad shield easily, is the only de-
velopment board that employs a real quartz oscillator. To
my knowledge, this board has been developed by a company
called RobotDyn. Unfortunately, it no longer seems to be avail-
able, but there are many replicas available from other compa-
nies. I have successfully tested the ARD MEGA2560PRO by
Joy-IT (SIMAC Electronics GmbH) and another unbranded
MEGA 2560 PRO board. Note: Do not confuse this board
with the very similar “MINI” variant, which does not have a
USB socket.
107
14.2. LCD Keypad Shields
MagicQuartz should work fine with the LCD keypad shields
that are available for Arduino and compatible development
boards. I have successfully tested the LCD keypad shield
by D1 ROBOT and an older SainSmart LCD keypad shield
V1.0.
108
