Author Topic: Mutton Chop - a Germanium Rump Roast!  (Read 1021 times)


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Mutton Chop - a Germanium Rump Roast!
« on: June 01, 2012, 11:20:34 PM »

My friend Keith has been jonesing for a Rump Roast ever since I introduced him to the Madbean site. So I built him one partly as a thank-you for retubing my amp for a recording session last week, and for taking me to the New York Amp Show this Sunday.

As I am wont to do whenever I see "J201" in the schematic (201s always sound harsh and raw to me), I pulled out my entire stash of NPN transistors and started testing. Oddly enough, I couldn't get any bipolar silicon transistors to work (not even the super low-gain ones). At first I was just going to stick with two 2n5457s, which pretty much always sound excellent (2Sk30s were better than the J201s, but not as nice as the 5457s), but on a whim I stuck a low-gain Ge transistor (HFE 50, leakage unknown but somewhat high, one of the unmarked cans from a smallbear bulk pack*) in Q2 and HOLY CRAP the circuit just came alive. It added a hint of compression and just a tiny bit more dirt on higher gain settings, but it's still sparkly. Very nice character.

*I got two of these unmarked Germaniums, and both have sounded phenomenal despite their high leakage. The other one is in my Little Teapot Rangemaster.
Myself's music & things I make: My band: PCBs of my designs from: (Bearhug Comp & Cardinal Harmonic Trem); (Hamlet+ delay & Blue Warbler envelope vibe); Snow Day OD/Flabulanche: