
antichef
pornk rock
As a data point, I swapped the BC457/BC447 in Q4/Q5 for BC461/BC441 transistors on the two EQ boards that have inductors in one of my ACMP81s, and the hum dropped dramatically. (was that zmix / Chuck Zwicky? so many threads on so many boards, I've lost track - anyway, thanks whoever you are!)
I may try it on the other 81, but that's the one that I might want to send back for other reasons, so I'm on the fence as to whether to mod it.
I may try it on the other 81, but that's the one that I might want to send back for other reasons, so I'm on the fence as to whether to mod it.