Help troubleshooting CF amps.....

I bought 2 in53529-tp. thats what bob originally suggested to use? they are 5w 15v. not right anymore?? did it change again?? someone please let me know!!!!!

I bought 2 in53529-tp. thats what bob originally suggested to use? they are 5w 15v. not right anymore?? did it change again?? someone please let me know!!!!!

These are rectifier diodes for the incoming power, NOT the zeners for the DC Restorer Circuit. I was short 2, so decided to upgrade them all.

ok thanks gary!! was thinking maybe I had to order something different, have not installed my zeners yet but amp works well so far!! I have some real nice new tubes in mine so they dont have a problem with it as is! thanks again!!

i am just lazy to look, but i bought a hundred diodes a while back, and they are up for grabs to those in need. i forgot though for sure, but i believe they are for the dc restorer. a pm with the address they need to goto is all that is needed.

No difference touching a wire between the chassis.

No voltage AC or DC between the chassis, but I get a WEIRD continuity reading between the two chassis' that sounds gutteral instead of the usual steady tone.....?

Here's more info--I get .28 VDC across the other end of the input between ground & positive/hot on one amp & .30 VDC on the other amp.

Video:

Well, swapped the wires (polarity) & still have the same problem. I'm beginning to think I may have a bad transformer.....

I don't think you have a bad transformer because the hum goes away when you unplug one amp. I wonder what happens if you can plug each amp into a different outlet?

Seems like a grounding issue.

Robin, I agree it DOES sound like ground issue, but I've not been able to fix it thus far with typical ground fault applications

OK, here's where I'm at:

[quote=martin1970;87383]
I thought Gary swapped the power transformer already.

This is what Mike wants you to do:

OPT swap suggestion.jpg (44.22 KiB) Viewed 166 times

Swap the output transformer leads on one amp.
Yes, I know that looks like 5hi7.

[/quote]

OK: tried this swap & got VERY BAD SOUNDS immediately. Sounded like a bomb whistling/dropping, followed by a very destructive sounding bass buzz getting lower & lower. Unplugged everything immediately. BAD CHOICE--note to self--don't try that again!

Also swapped the incoming power wires with no effect.

Another observation: The constant buzz sounds out of phase on the speakers; if I swap speaker leads it's in phase. However, then the music is out of phase.

Robin, I agree it DOES sound like ground issue, but I've not been able to fix it thus far with typical ground fault applications

OK, here's where I'm at:

[quote=martin1970;87383]
I thought Gary swapped the power transformer already.

This is what Mike wants you to do:

OPT swap suggestion.jpg

Swap the output transformer leads on one amp.
Yes, I know that looks like 5hi7.

OK: tried this swap & got VERY BAD SOUNDS immediately. Sounded like a bomb whistling/dropping, followed by a very destructive sounding bass buzz getting lower & lower. Unplugged everything immediately. BAD CHOICE--note to self--don't try that again!

Also swapped the incoming power wires with no effect.

Another observation: The constant buzz sounds out of phase on the speakers; if I swap speaker leads it's in phase. However, then the music is out of phase.[/quote]

Rabbit, if you keep getting these sounds, switch ONE channel's pin 7 wires if it is suppose to be a mono block. I had this same issue with Wayne's amps. I built them both and couldn't figure out why it was freaking out, then I realized I had mirrored the components but not the wiring.

Hope this helps,

Alex

"Rabbit, if you keep getting these sounds, switch ONE channel's pin 7 wires if it is suppose to be a mono block. I had this same issue with Wayne's amps. I built them both and couldn't figure out why it was freaking out, then I realized I had mirrored the components but not the wiring.

Hope this helps,

Alex"

Alex,

Why did I not have to do this on the other pair of monoblocks I built?

"Rabbit, if you keep getting these sounds, switch ONE channel's pin 7 wires if it is suppose to be a mono block. I had this same issue with Wayne's amps. I built them both and couldn't figure out why it was freaking out, then I realized I had mirrored the components but not the wiring.

Hope this helps,

Alex"

Alex,

Why did I not have to do this on the other pair of monoblocks I built?

No idea, just throwing out one more option that could be ruled out.

Crap. Amp #3 now blows the mains fuse every time I apply power to it.

Buzz is still there on #4 when they're both plugged in. No closer than I was before, but now I have a DOA amp.

would a bad CAP do this????

maybe one of the 2 big caps is bad?

or one of the 600v 0.1uf caps

I think I read this some place, more likely to happen on the old stuff. but now that I read what your #3 amp is doing, it came to mind

you could also try the DIY site. there are some really good tube amp trouble shooting guys on there.

when the problem is found it will most likely be a moment....

Thanks, Mike. I'm beyond my capability with these now. I sent Bob an email with link to this thread.....we'll see what happens.