MagicQuartz Arduino Breadboard Version

This is another simple, breadboard-based version based on standard Arduino hardware. Please be sure to have read the basic information about the limitations of this Arduino version. This also contains very important security information – you don’t want to blow your computer’s USB ports!

It is better than the Arduino Motor Shield version and produces a perfect sine wave, because it uses the same power amplifier as the real MagicQuartz unit does.

The schematic below also includes the (optional) optical sensor CNY70 for “live quartz mode” in the upper left corner.

MagicQuartz Breadboard Arduino Version L6202 L6203 turntable speed box power supply

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The required components are:

  • An Arduino Nano or an Arduino Uno. You can also use a cheap Chinese clone.
  • A laboratory power supply, capable of providing 1A at 24V.
  • A quality 230V to 12V toroidal transformer with at least 30VA. The recommended type, which is also used in the MagicQuartz DIY kit, is the RKT 5012 transformer, which can be obtained here: RKT 5012. The transformer will be used in reverse, i.e. to step-up the voltage from 24V to 230V (or 110V).
  • A quality 220nF/1000V capacitor. Recommended type is WIMA MKS-4.
  • Either a L6203 (which is also used in the “real” MagicQuartz) or a more breadboard-friendly L6202 amplifier. Possibly a heat sink for the amplifier.
  • Two 15nF capacitors, one 22nF capacitor and one 220nF capacitor.
  • One 10 Ohm resistor.
  • Breadboard, some wires.

Assembly Instructions

Be careful! This circuit generates high voltage. A small mistake can kill you!!!

Tip: Although the schematic above also shows the pin connections for the L6202/L6203, please feel free to refer to the data sheet of these chips. It can be found here.

  1. Flash the Arduino firmware as explained on this page. Be sure to use the firmware for the L6202/L6203 (Breadboard) version, which can be downloaded on the Downloads page.
  2. Amplifier (L6202/L6203): The amplifier needs to be installed as shown here. Connect BOOT1 and OUT1 with a 15nF capacitor, and BOOT2 and OUT2 with the other 15nF capacitor. Put the 22nF capacitor and the 10 Ohm resitor in series between OUT1 and OUT2. Connect the 220pF capacitor between VREF and GND. Connect VS to 24V DC (use a thicker wire, breadboard jumpers can not deliver enough current). Connect SENSE and GND to the common ground.
  3. Transformer: Please keep the 24V rail (laboratory power supply) switched off until everything has been finished! The transformer’s 12V tappings need to be connected between OUT1 and OUT2 on the amplifier. If your transformer has two windings (e.g. 12V + 12V), connect both in parallel. Connect the 220nF/1000V capacitor between the 230V tappings of the transformer. These two tappings also power the turntable (as as shown here in “Stage 2”.)
  4. Connection between Arduino and amplifier: From the Arduino, connect D11 and D3 to IN1 and IN2 of the amplifier. These two pins deliver the half sine waves. Connect the +5V pin on the Arduino to the ENABLE pin of the amplifier. Connect the Arduino ground (GND)  to the common ground with the amplifier.

The Arduino needs to be powered on its USB port, and the amplifier is fed by the 24V laboratory power supply.

If everything is set up, it should work. Before switching everything on, please make sure that you are fully aware of the following dangers:

  • Be careful! This circuit generates high voltage. A small mistake can kill you!!!
  • You do this entirely on your own risk!
  • Do not connect turntables with AC motors that rely on phase-shifting capacitors. These were build for a fixed frequency only (e.g. 50 or 60 Hertz). The variable frequency that can be generated by MagicQuartz may damage such turntables.
  • Do not connect “modern” direct drive turntables.
  • Do not connect IEC protection class 1 or 01 appliances to the circuit. These are turntables that have a separate ground wire in their cable and a three pole power plug. In the unlikely event of a failure inside the turntable, the turntable’s chassis would draw a high voltage. Only connect IEC protection class II appliances. These are turntables that have a two pole power plug.

This schematic also includes the connection of the CNY70 optical sensor. Please follow the instructions on this page for details!