Well-known member
Build Rating
5.00 star(s)
Yo @cdwillis this is a great circuit!

I'm super thankful he sent me this one. I am a big fan of Muffs and MKII and MKIII TBs so this was right up my alley. To get a more detailed explanation of what's this is, refer to his build report


Essentially it is a combination of a Russian muff and a MKII/MKIII TB. And the best part it has a bias pot for some very cool sag-like/voltage-starve-like functionality.

I went with 2N3903 transistors because they were the lowest hfe NPN silicons I had. But, I think it sounds great with a little lower hfe. I socketed them in case I want to experiment but for now I think it sounds awesome.

My mistake was I initially installed a B100K pot for the bias and that caused the bias to be useless only at the very end of the sweep. As seen in the gut shot. After I re-read @cdwillis report again, I went back and replaced it with a B10k pot and the sweep is much better.

One thing I will not on the layout is that I much more prefer how the jack input/output connections are on the tip of the board like this one. I just think it's a cleaner look.

Not super happy with how my enclosure drilling came out or how the color came out but I really dig the powderkeg image.

Anyway, Kudos @cdwillis !

Also check out @BuddytheReow build report on this one. Great write up and awesome looking paint job.


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Very nice. BMP are one of my favorites I haven’t build one with a bias yet. I like how clean the wiring is with the in and out from the breakout board ran back down to the main.