08-22-2016, 07:06 AM
Thanks for the quick response!
Regarding the "early breakup", that was before I rebuilt the power supply, and it was breaking up at low volumes (before 11). I think that was mostly due to the under-rated filter caps that I replaced, though. It's getting louder and staying smoother now, not to mention a lot quieter!
If A and B are okay, then mostly I'm just worried about the power tubes being biased cold. 17mA is pretty darn cold, right? If it's fine, then I guess I don't have too much to worry about.
I removed the adjustable bias mod because I've seen plenty of posts talking about how adjustable bias is unnecessary in these amps, and they're biased conservatively as part of the design. I can always add it back in though.
I do have a scope, but it's an old Tek 454 I bought to play around with and maybe restore eventually. I doubt it's in spec, and some dingus cut off the ground pin on the power cable, so I'm not sure I'd feel comfortable using it around ~500 volts until I replace that. I can get access to a more trustworthy scope if I need to.
Regarding the "early breakup", that was before I rebuilt the power supply, and it was breaking up at low volumes (before 11). I think that was mostly due to the under-rated filter caps that I replaced, though. It's getting louder and staying smoother now, not to mention a lot quieter!
If A and B are okay, then mostly I'm just worried about the power tubes being biased cold. 17mA is pretty darn cold, right? If it's fine, then I guess I don't have too much to worry about.
I removed the adjustable bias mod because I've seen plenty of posts talking about how adjustable bias is unnecessary in these amps, and they're biased conservatively as part of the design. I can always add it back in though.
I do have a scope, but it's an old Tek 454 I bought to play around with and maybe restore eventually. I doubt it's in spec, and some dingus cut off the ground pin on the power cable, so I'm not sure I'd feel comfortable using it around ~500 volts until I replace that. I can get access to a more trustworthy scope if I need to.