Not sure this is the right place for this but …
Just populated and tested 4 of the Catalinbread jFET drives and while they all worked apparently fine the output of the Covert Overdrive was drastically lower than the others, in fact in Super Bass mode max volume was almost exactly unity when powered with 9v. At 18v the volume seemed ‘normal’.
Did a forum search and found a few threads mentioning low output volume with an otherwise normal sound but none said whether they found a a solution or just ended up living with it.
Did a comparison with the Tweed Man (built at the same time) which is largely the same circuit and the size of the resistor at the input of the tone stack is hugely different - 33k as opposed to 100k on the Covert and when I audio probed - this is where the volume drop occurs.
Looked at the online tone stack calculator and couldn’t see that halving the 100k to 47k made that huge a difference to the eq curve but would bring the volume back.
47k in R14 instead of 100k and all is hunky dory - good output now and still sounds Marshally. I also changed C18 from 100n to 22n as recommended elsewhere.
Without lowering that resistor the output was borderline unusable at 9v (imo).
Hope this helps someone else running a search for the same issue.
Just populated and tested 4 of the Catalinbread jFET drives and while they all worked apparently fine the output of the Covert Overdrive was drastically lower than the others, in fact in Super Bass mode max volume was almost exactly unity when powered with 9v. At 18v the volume seemed ‘normal’.
Did a forum search and found a few threads mentioning low output volume with an otherwise normal sound but none said whether they found a a solution or just ended up living with it.
Did a comparison with the Tweed Man (built at the same time) which is largely the same circuit and the size of the resistor at the input of the tone stack is hugely different - 33k as opposed to 100k on the Covert and when I audio probed - this is where the volume drop occurs.
Looked at the online tone stack calculator and couldn’t see that halving the 100k to 47k made that huge a difference to the eq curve but would bring the volume back.
47k in R14 instead of 100k and all is hunky dory - good output now and still sounds Marshally. I also changed C18 from 100n to 22n as recommended elsewhere.
Without lowering that resistor the output was borderline unusable at 9v (imo).
Hope this helps someone else running a search for the same issue.
