MagicQuartz FAQ

This page aims to answer some of the most frequently asked questions (FAQ) about the MagicQuartz firmware for turntable speed control. If you have another question, please send me an e-mail. I will be happy to help.

I smell snake oil!

There is no snake oil involved. It’s rather plain, yet effective math and clever microcontroller programming.

Can you really hear the difference?

The short answer, which may surprise you: No, you probably can’t hear it.

The long answer: It depends. There are three main causes of speed deviations during record playback: mains frequency fluctuations, stylus friction (which decreases during playback), and lubricants in the drive warming up (which accelerates the record player). All errors add up. While you should not be able to notice the effects of first two error types, those of the third one can be significant, depending on the turntable. The speed drifts may become noticeable if you are very familiar with the recording or perform an A/B test. Of course, you usually don’t do this, and since the drifts occur over several minutes, you generally do not notice them. But they are there. I have provided measurements on the downloads page that analyze these effects in detail. They are also outlined in my YouTube video.

Fortunately, you don’t have to settle for that, as these speed errors can be measured and corrected. MagicQuartz provides an easy-to-use and economic solution for this. In my humble opinion, there is no good reason to go without a turntable speedbox, especially if the goal is accurate playback speed.

This is great! Where can I buy the speedbox?

I do not sell any hardware — neither a finished speedbox nor a kit. I also have no plans to do this in the near future. If you would like to own a MagicQuartz-based turntable speedbox, you will have to build it yourself. The straightforward, open-source hardware design of the MagicQuartz TechDemo could be a good basis for this.

Nevertheless, I would be grateful for expressions of interest in finished devices or kits, as this would enable me to understand the demand. Simply drop me an e-mail.

What is the status of the project? Is it finished?

Yes, the project can be considered complete, but there will certainly be updates and improvements in the future.

How much does it cost?

The proprietary MagicQuartz firmware is currently available free of charge. All other information and resources are permanently free. The TechDemo hardware design, for example, is provided under an open source license. If you would like to activate a MagicQuartz license now or reserve this option for later, simply send me an e-mail: Contact Information

It looks as if the speed is only measured once per platter revolution. How can short-term fluctuations be compensated for?

MagicQuartz does not compensate for short-term speed fluctuations (wow and flutter). It compensates for slow drifts that occur over several seconds or minutes. The speed regulation deliberately reacts rather slowly.

MagicQuartz was developed for turntables with a rather heavy platter, where wow and flutter are inherently compensated for by inertia. And these don’t have to be high-end “oil rig” turntables — in fact, most vintage mid-range turntables should already fulfill this characteristic. Although more sophisticated means of measurement could be applied to measure and adjust the speed more often than once per revolution, it can be assumed that constantly decelerating and accelerating a heavy platter is not sensible because it may put mechanical stress on the drive.

It is good to know that MagicQuartz implements clever programming to quickly restore the speed at the beginning of a record (see documentation, parameter SaveHzAtSec) and to pause the regulation when the stop function of an automatic turntable is activated. It can also handle measurement errors efficiently.

Will MagicQuartz work with my turntable?

MagicQuartz should work with any turntable equipped with an AC motor, although certain limitations may apply. In general, the automatic speed control (“Live Quartz Mode”) works with all motor types (synchronous, asynchronous, and regardless of whether these uses phase-shifting capacitors). The electronic speed switching (e.g., between 33 and 45 rpm), the transpose function, and the automatic voltage reduction however may not fully work with asynchronous motors due to their inherent slip. Also, the electronic speed switching and transpose functions should not be used if phase-shifting capacitors are present (both on synchronous and asynchronous motors). Please refer to the documentation and my tests (Downloads => Turntable-Compatibility-Chart.zip) for details.

The documentation often mentions 220V and 50Hz. Will it also work with my 120V/60Hz turntable?

Yes, of course. The nominal frequency of the turntable can be set between 40 and 70Hz (parameter DefaultHertz). The maximum voltage is determined by the hardware design and can be reduced to arbitrary lower values via the parameters VoltageMtOff, VoltageMtOn, and VoltageMtRed (see documentation).