• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

a question for valve experts

If and its a big if, i decide to upgrade the signal caps/resisitors in my amp could anyone tell me from the photo what ones are in the signal path,i think from memory the yellow caps are MKP . Large black ones are Kemet.


IMG-3028.jpg
 
thanks for your reply,i dont think they are far off the 10 year mark to be honest although i cant be sure.
I wouldn't bother with the caps yet. If you really want to change the resistors, it would be more interesting
to do those now and hear the difference, without the complication of also changing capacitors at the same time.

Or else change the caps now, and wait on the resistors. Just don't do both at the same time.
 
It looks like a nice piece you have there. Technically, they're all in the signal path, but by appearances, you'd probably be best to just leave it as-is. Perhaps look at what's in front (driving) and behind (driven) your apparently fine tube power amplifier for sonic improvements.
 
It looks like a nice piece you have there. Technically, they're all in the signal path, but by appearances, you'd probably be best to just leave it as-is. Perhaps look at what's in front (driving) and behind (driven) your apparently fine tube power amplifier for sonic improvements.
thanks,yes leaving it alone is probably the best thing to do,i just wondered if by using better tolerance parts i'd gain a small improvment.
 
It looks like all of the critical resistors are already 1% types, and the capacitors appear to be decent quality. I would probably just leave it alone. I generally use teflon foil coupling capacitors in my designs, but they are extremely expensive and hard to justify from a measurement perspective.
 
Agree with rayma. If it's quite recent, then perhaps the only Electrolytics you may want to check are the Big PSU filter caps. They might still be good though. BTW, I've seen several people like Kemet caps.

It's a SET?

Enjoy it!
 
Quite true - technically everything is in the “signal path” including the power supply. Maybe with the exception of auxiliary loads such as the blue LED power indicator or the controls for a soft-start circuit. But if they generated noise it could still bleed into things as complete isolation is impossible.

Don’t crawl down any rabbit hole that you’re not willing to follow all the way to China. You can end up spending a fortune.
 
It's a SET?

Enjoy it!
It is not SET. It appears to be a push pull KT88 amp in Ultralinear configuration. There are two wires from each OPT to each output tube, the giveaway for UL. The octal twin triodes (6SN7's) are the LTP phase inverter, and the KT88's are the output tubes. The yellow caps near each KT88 socket are the coupling caps and the ones that most tweakers change. Can't tell much about the input stage. I am also of the opinion that it is best left alone since it looks well made, so at best minimal improvements could be made. The opportunity to make things worse is likely far greater than the possible improvements.