Drunk Beaver's Disambiguation Distortion is a really cool confection of Rat Circuit inserted into a Muff Gain Stage

There have been a number of pedals over the years which have combined the characteristics / voicings of Big Muff and Rat circuits - like two of my favourites - the Dr Scientist Frazz Dazzler, and TX Pedals Animalizzer - which you can tune one way or the other. But not many if any which have perfected the combination of those two celebrated circuits - essentially Rat and Muff amalgamated within the same compact enclosure.

So the circuit kind of starts off as a Russian / Red Army Big Muff topology where instead of the Muff input boost stage, you insert a Rat input/gain stage with UD1408B chip, no filter, no diodes. The signal then travels through 2 Big Muff transistor gain stages with KT3102EM transistors, and KD521A diodes. Next it passes through a classic BMP tone stack, with specs close to a Ram’s head, and finally as a gain recovery / output state - there is a JFET gain stage (MMBF4393 SMD JFET).

Obviously loading a Rat into a Muff circuit will deliver sustain for days, alongside some interesting harmonic textures. You do need to be careful not to oversaturate and over-compress the output by having the gain set too high. The sweet spot for the gain for me is around 2 to 3 o’c, and for a perfect balance of frequencies the range is around 11 to 1 o’c for my preferences, where I mostly have the Gain on 2 o’c, and the Tone at 1 o’c. Same goes for the volume - which above 4 o’c adds further compression and distortion density - so I tend to position it mostly at 4, but occasionally drop it back to 3 o’c. My perfect balance of this circuit is with those last 3 mentioned settings (2 - 4 - 1 o’c).

Moving the dial left of centre delivers more Bass, but you can loose clarity and definition. Obviously results will vary between rigs - where for me the perfect soundstage is set within fairly precise margins.

The combination of Rat and Muff doesn’t necessarily bloom in the same way as those do individually. What you do get is a quite distinct blend of those two celebrated voicings - where it certainly carries characteristics of both - and as mentioned above - it has incredible amounts of sustain.

Loading one circuit into another can often narrow the output in terms of how the sound is formed and compressed. For fans of both circuits - this is definitely a new and unusual combination that works really well at delivering a distinct tone that sits somewhat midway between the two most of you know so well.

For me it’s certainly sufficiently distinct to warrant a place in most collections - and having just 3 dials means it’s really very ease to dial in - with plenty of range - bearing in mind the guidelines I have laid out above.

A fresh batch of Disambiguation Distortions has just hit the Drunk Beaver Reverb.com store. Available right now for a very reasonable $120. Those dark army green enclosures with raised graphics and milled aluminium knobs look gorgeous too!