An old super rare DBA pedal which was a two channel fuzz. Here is the transistor channel which resmebles most older DBA designs; cascaded reverse beta transistor gain stages. Socketing your transistors is a must since you need to find ones that doesn't gate too much. Also, there is a Filter control which is a variation of twin notch filter. Shape control is a simple ground lift for the filter circuit.
A big thank you to Nils at Moonn Electronics for the trace!
Schematic is avaiable HERE.
And you can tag this one too!!! Very much a DBA pedal, you really need to test a bucket of transistors. I found the best results by matching the hfe of Q1 & Q2 (I used 5088's at 430hfe) and Q3 & Q4 (MPSA05 at 170hfe). Unmatched transistors didnt really work, all 5088's was too gated, all low gain was bad so I think I found the best using the above combination
ReplyDeleteAce! I still have a bunch of specific 5088s that worked for my v1 fuzz war, was planning on using those but might try out your suggestions instead.
DeleteOh, and I used a B500K dual gang instead of a A250K dual gang and I think I got away with it - it is pretty wild
ReplyDeleteBreadboarded it. 5089 at Q1-2 and 3904 Q3-4 worked nicest for me. I'd describe the circuit as a v1 fuzz war ancestor. I'll breadboard the opamp side later and decide then if I want to build or not, not fully onboard with it yet.
ReplyDeleteThe best part of the op amp side is the feedback footswitch. I'm not usually a fan but this one is pretty good, especially with a Pitch Pirate or wonky delay on the other side
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DeleteJust working on that one. Having a bit of bother making it work at the moment! It works for about a few seconds then sputters out, yet my tone generator is saying the paths good! Well odd...I shall double check it all.
ReplyDelete