The Drunk Beaver Kharkiv Supercharged CMOS Overdrive is a limited-run overdrive pedal from Ukrainian builder Drunk Beaver, priced at $150. Its gain stage is an inverting amplifier soft clipping design built around a NOS Tesla MAA741 metal can op-amp and Tesla Si diodes, voiced differently and with a lower gain level than the builder's Stone Gray circuit.1
Where it came from
The Kharkiv Supercharged CMOS Overdrive is a small-batch release from Drunk Beaver, offered at $150. It shares its core gain architecture with the builder's Stone Gray: an inverting amplifier soft clipping stage using a NOS Tesla MAA741 metal can op-amp and Tesla Si diodes, though it is voiced differently and runs at a lower gain level than that pedal.1
The Kharkiv Supercharged CMOS takes some ideas from Mad Professor's Stone Gray Distortion and also Catalinbread's Supercharged Overdrive, without exactly matching either. Karlsson names the Catalinbread Supercharged as the nearest sound reference, "but not quite!"1
The circuit
The pedal's gain stages run on NOS Toshiba TC4007 CMOS chips. The topology, as Karlsson describes it: the main gain stage is configured to have a lowpass around 860Hz, then two CMOS inverter gain stages follow, and an additional CMOS gain stage sits in a negative feedback loop using those same NOS Toshiba TC4007 parts.1
Like the Stone Gray, there is an inverting amplifier soft clipping stage, voiced differently and with a lower gain level than the Stone Gray. That stage uses a NOS Tesla MAA741 metal can op-amp and Tesla silicon diodes.1
Controls
The pedal has four controls: Contour, Tone, Volume and Drive.1
| Control | What it does |
|---|---|
| Contour | Shapes low-end and mids, with lowpass filters at 1kHz; part of the feedback loop |
| Tone | Controls the slope of the lowpass, from -3dB/Oct to flat; part of the feedback loop |
| Volume | Output level1 |
| Drive | Gain1 |
The Contour and Tone controls are unusual in that both are part of the feedback loop and interact with each other, and both impact gain and saturation. In practice, turning one changes how the other behaves, so the two act as a coupled voicing pair rather than independent filters.1
What reviewers said
Guitar Pedal X's Stefan Karlsson reviewed the pedal at its August 2025 release and was strongly positive, writing1:
"I'm very much looking forward to getting my hands on mine - I feel this is going to be one of the Pedal Drop Greats!"
With only 40 units made, this pedal is a limited edition. Drunk Beaver's other Pedal Drop releases, such as the Kherson Drive Retro Edition and the Okhtyrka Honey Bee Overdrive, have followed the same small-batch format.
Related pedals
The pedal most directly related in the Drunk Beaver range is the Stone Gray, which uses the same inverting amplifier soft clipping stage built on a NOS Tesla MAA741 metal can op-amp and Tesla Si diodes; the Kharkiv Supercharged CMOS Overdrive is voiced differently and sits at a lower gain level. For context on the wider category, see Overdrive Pedals and Distortion Pedals.1
Questions
How many Kharkiv Supercharged CMOS Overdrive pedals were made?
It is a limited edition: Guitar Pedal X reports that only 40 units of the Kharkiv Supercharged CMOS Overdrive were made. It was released on August 7, 2025 as Drunk Beaver's Pedal Drop #31, priced at $150. Like the builder's other Pedal Drop releases, once the run sells through it is gone, so the pedal is best understood as a small-batch release rather than a continuously produced product.
What pedals is the Kharkiv Supercharged CMOS Overdrive based on?
According to Guitar Pedal X, the Kharkiv Supercharged CMOS takes ideas from Mad Professor's Stone Grey Distortion and Catalinbread's Supercharged Overdrive, without exactly matching either. The reviewer names the Catalinbread Supercharged as the nearest sound reference, though not quite. The soft clipping stage follows the Stone Grey's approach, voiced differently and at a lower gain level.
What do the Contour and Tone controls do on this pedal?
Both are part of the circuit's negative feedback loop, so they interact with each other and affect gain and saturation. The Contour control shapes the low end and mids, with lowpass filters at 1kHz. The Tone pot controls the slope of the lowpass, from -3dB per octave to flat. Because they sit in the feedback loop, adjusting one changes how the other behaves.
Who designed the Kharkiv Supercharged CMOS Overdrive?
The pedal was designed by Vitalii Bobrov, the builder behind Drunk Beaver. Guitar Pedal X's Stefan Karlsson, reviewing the release in August 2025, noted that Vitalii had been on something of a roll recently and expected the Kharkiv Supercharged CMOS to be one of the Pedal Drop Greats.
Which chips does the Kharkiv Supercharged CMOS Overdrive use?
The CMOS gain stages use NOS (new old stock) Toshiba TC4007 chips made in 1984. The soft clipping stage uses a NOS Tesla MAA741 metal can op-amp together with Tesla silicon diodes. The use of vintage Soviet-era and Japanese stock parts is a recurring feature of Drunk Beaver's Pedal Drop series.
Which Pedal Drop number is the Kharkiv Supercharged CMOS Overdrive?
It is Pedal Drop #31 in Drunk Beaver's limited-run series. The series began on August 25, 2022 with the Kherson Drive, and the Kharkiv Supercharged CMOS Overdrive was released on August 7, 2025 at $150 in a run of 40 units.
Sources (1)
- Guitar Pedal X, Guitar Pedal X, 2025-08-07
