Quark kit

The Quark Overdrive is a clone of the Maxon OD-880 Overdrive / Soft Distortion, originally released in 1976.

The Clipping switch mod allows you to set up a second set of diodes to toggle back and forth from stock. Extra pads have been provided so you can stack two diodes in a row if desired. (The middle two pads are connected in each diode.) If you use a SPDT center-off switch, the middle position becomes a diode lift mode, but you can also use a regular SPDT if you don?t care about this.

The EQ switch changes the tone stack from stock to modded. The biggest criticism of this circuit is that it cuts too much bass, so this mod gives more bass and fullness and changes the overall gain structure of the effect. Note that this mod doesn?t have an ?off? mode like a clipping switch or a capacitor mod would, so don?t use a center-off switch here. Just use a normal two-position SPDT.

This kit contains the PCB and all necessary parts. The enclosure can be selected, please select 2 knobs for 6,3mm shaft separately.
Here is the bill of material: bill of material

This project is by Aion Electronics, in collaboration with Musikding. If you have any problems with the contents of the kit, please contact Das Musikding (Klaus). Since the modifications require some basic knowledge, this project is rather for more experienced builders.

Here is the direct link to the manual with layout and schematic:
Instructions

Here you can find build reports on this project: Build Reports