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Low gain transistors in a Tonebender Mk II?

Started by MarkL, January 29, 2019, 11:27:45 PM

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MarkL

I've managed to secure several Mullard OC-series germanium transistors (OC74s and OC76s) that are just the right leakages for a TB MK II, but pretty low gain.  Most are around 35-50Hfe. 

I seem to recall a discussion thread somewhere on another site where someone noted that even these low gains would still work for the circuit with some tweaks.  If memory serves, this involved tweaking the collector resistor on Q1 to be 12-15K rather than 10K.  I can't remember more from the discussion (and of course now, I can't find it!), but I also wonder whether upping the Q2/Q3 feedback resistor to be closer to 150K might help too. 

Does any of this sound feasible to you all?  Can low gainwers like these still work in this circuit with sufficient tweaking/tuning?


Scruffie

I might have been involved in that thread and yes, low gainers can sound great in a TBMKII, even without tweaks.
Works at Lectric-FX