Rectifier tubes and sag

[pdf64]

It may be that your operating conditions are very close to / at / past / class A; if so, there won't be much sag.
What is the power tube cathode voltage at idle, and then when being overdriven hard?

[lowell]

Reduce your filter caps to 22uf/16uf etc.. Make sure that 100ohm is good. Possibly increase it's value a bit. Make sure your screen resistors on the 6v6 are good. For more sag increase the value of the screen resistors, then rebias to spec.

Not sure why the Rscreen would need to be increased in this amp as it should have a good amount of sag.... but worth a try. Is the stock Weber output transformer in there? If it's an upgrade or bigger output transformer that will reduce sag as well.

If you have little to no overdrive with the amp cranked, something is DEFINITELY wrong. Check all the voltages on all tubes. Try new tubes as well.

[loudthud]

Check this thread: http://music-electronics-forum.com/t24269/

Especially the last post by Bruce. He tells about a common wiring mistake that his customers sometimes make.

[Yahoobuckaroo]

Just so you know where I'm at, I've tested all the 6V6 resisters, and they're fine. I've changed all the tubes, some of them more than once, and they were all apparently fine. I'm having a hard time getting my probes in there to test that 100K resister. I'll work on it more tomorrow and try to take some voltage readings as well.

[lowell]

Loudthud has a great suggestion there too. Definitely check that

[Yahoobuckaroo]

Oh, I intend to check out everybody's suggestions. I just didn't get much time today. My only electronics training was in computer repair. There's a lot I don't know about amplifiers including some of the terminology. I do have the stock Weber output transformer by the way.

[Yahoobuckaroo]

I still haven't taken any voltage readings, but I did find time to check every resistor in the amp except for the ones wired into the input jacks. That 100R/25W resistor (R32) always reads high, generally around 125K. I realize it needs to be changed, but do you think that's far enough off to be causing my problems?

Also, it's a small thing, but I noticed that 64k was used for the R3, R4, R5, and R6 resistors instead of the specified 68k. I wouldn't think that would make a difference though.