The C12H23 Overdrive PCB is a do-it-yourself circuit board from Griffin Effects that reproduces an overdrive based on the Diezel VH4, the German amp maker's flagship head. Instead of buying a finished pedal, you populate the board yourself with parts ordered from the supplied Mouser list, then wire it into an enclosure. It sits alongside Griffin Effects' other build-it-yourself boards such as the Super Screamer PCB and the SD-1 Supercharged Kit, and it belongs to the broader family of overdrive pedals1.
The circuit and what it is based on
Griffin Effects lists the board as "Based on the Diezel™ VH4 Overdrive"1, so the design follows the overdrive section of that amplifier rather than a standalone stompbox circuit. The product reference is C12H23PCB1. As with any bare PCB, the board itself does not make sound until it is populated with components, wired to pots, jacks and a footswitch, and housed in an enclosure.
Building it: parts, enclosure and drilling
Griffin Effects supplies a Mouser project parts list covering all parts except potentiometers, so the pots need to be sourced separately1. The maker notes that the parts lists were created choosing the best possible parts and availability at the time, and asks builders to report any mistakes or items that have reached end of life1.
- Enclosure: designed to fit a 1590BB with top mounted jacks, though the jack position is flexible1
- Drill template: a Tayda Electronics drill template is available1
- Bypass: buffered bypass as designed, and the maker says it "can be made true bypass fairly easy"1
The buffered bypass means the pedal's switching includes an active buffer stage. Builders who want hardwire true bypass can modify the design, but that is a change to the standard wiring rather than the default.
Price and availability
The board is listed at $19.991. For comparison with finished pedals rather than bare boards, see the overdrive and distortion type pages.
Questions
What circuit is the Griffin Effects C12H23 based on?
Griffin Effects describes the C12H23 as an overdrive PCB based on the Diezel VH4 overdrive. It is a bare board for builders to populate themselves, with a Mouser parts list supplied so the components can be ordered directly. The board is designed to fit a 1590BB enclosure with top mounted jacks.
What enclosure does the C12H23 PCB fit?
The board is designed to fit a 1590BB enclosure with top mounted jacks. Griffin Effects notes that the jack position is flexible, so builders have some room to arrange the layout inside the box rather than being locked to one placement.
Is the C12H23 PCB true bypass?
The circuit has a buffered bypass as designed. Griffin Effects states it can be made true bypass fairly easily, so builders who prefer hardwire switching can modify the wiring when they assemble the pedal.
Does the Mouser parts list include potentiometers?
No. Griffin Effects provides a Mouser project parts list for the C12H23 that covers all parts except potentiometers, so those need to be sourced separately.
How much does the Griffin Effects C12H23 PCB cost?
The C12H23 Overdrive PCB is listed at $19.99 on the Griffin Effects product page as of 26 October 2026.
Is there a drill template for the C12H23?
Yes. A Tayda Electronics drill template is available for the C12H23, which helps with marking and drilling the enclosure holes for the switches, pots and jacks.
Sources (1)
- C12H23 Overdrive PCB, Griffin Effects