Just built this the other day. When biasing I was unable to get Q3 below 6.4v. The recommendation in the build guide was to shoot for 5v. It sounds fine to me but I don’t know what it would sound like at 5v to compare. I was able to get Q1 and Q2 right at 5v.
I have a couple dozen 2N5457’s (bought from legitimate sources…here and SB). I also have a DCA55. Is there a way I could test what I have against the one I used to try to select one that will bias correctly? My knowledge of the DCA55 only extends as far as testing Ge transistors for gain and leakage…and double checking pinouts.
I would prefer to not attempt to desolder the trimpot or add a resistor in series somehow…or randomly plug in the other 2N5457’s trying to get it in the 5v range.
Thanks for the suggestions. I messed with the bias of 1 and 2 a little bit but didn’t try them both slightly above Q3. I will start there.
And, you are right, not too tough to tack that resistor on the bottom of the board…my mind went straight to putting a higher value trimmer in there and was not looking forward to that. Not of a fan of having to desolder…
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