Xploration • Curation • Recommendation
For Pedal Drop #31 - the Kahrkiv Supercharged CMOS Tube-like Overdrive - Drunk Beaver takes inspiration from the Mad Professor Stone Grey Distortion and Catalinbread Supercharged and builds something much greater than the sum of its parts
Key Points
Drunk Beaver Pedal Drop #31 — the Kharkiv Supercharged CMOS — is a tube‑like, Marshall‑esque overdrive inspired by Mad Professor Stone Grey Distortion and Catalinbread Supercharged (Catalinbread is nearest).
Controls: Contour, Tone, Volume, Drive. Circuit: inverting soft‑clip stage with NOS Tesla MAA741 and Tesla Si diodes; main gain lowpass ≈860Hz; two CMOS inverter stages plus an extra CMOS stage with negative feedback using NOS Toshiba TC4007 (’84).
Contour affects low end/mids and a 1kHz lowpass; Tone varies lowpass slope from −3dB/oct to flat; both interact and change gain/saturation for dynamic response. Only 40 made. As of 2026-07-13, the price was £150.
So, the Kharkiv Supercharged CMOS takes some ideas from Mad Professor’s Stone Grey Distortion and also Catalinbread’s Supercharged Overdrive, but in the end it doesn’t exactly match the profile of either of those - while it does deliver something closer to the Catalinbread Supercharged than the Stone Grey - where the result is quite a dynamic tube-like overdrive with Marshall-esque tones / overtones.
Controls - Contour, Tone, Volume, Drive.
Like the Stone Grey, we have an inverting amplifier soft clipping stage (voiced differently and with a lower gain level) using NOS Tesla MAA741 metal can op-amp and Tesla Si diodes.
The main gain stage is configured to have lowpass around 860Hz. Then we have 2 CMOS inverter gain stages and an additional CMOS gain stage with negative feedback loop (something similar to the Catalinbread design but the voicing is completely different), Those use superb NOS Toshiba TC4007 - made in ’84.
The feedback loop has a Contour control that affects low-end and mids + lowpass filters at 1kHz. The Tone pot controls the slope of the lowpass from : -3dB/Oct to flat.
Both Tone and Contour controls are part of the feedback loop and interact with each other + impact on gain/saturation. The overall Overdrive sound is kinda cranked Marshall and reacts nicely to input signal - for super dynamic playback.
The Kharkiv Supercharged CMOS Overdrive is Drunk Beaver Pedal Drop #31, and can be yours for just $150 - courtesy of the Drunk Beaver Rocks Webstore. Only 40 of these will be made. 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!
If you love Tube-like Marshall-y action - then you should really love this Kharkiv Supercharged - I’m certainly expecting good things - as Vitalii has been on something of a roll recently - don’t forget to check out his new version of the TS-15 Trainer - which is utterly magnificent!
Sound reference samples - Catalinbread Supercharged is nearest (but not quite!)
![Drunk Beaver releases Pedal Drop #37 - the Bashtanka Muff on Π Pi Day [3.14] - a cool Big Muff 2 OpAmp Fuzz take](https://d6a2e7ghqts3o.cloudfront.net/AcuCustom/Sitename/DAM/571/2026-GPX-Drunk-Beaver-Bashtanka-BM2-700.jpg "Drunk Beaver releases Pedal Drop #37 - the Bashtanka Muff on Π Pi Day [3.14] - a cool Big Muff 2 OpAmp Fuzz take")
