Tube amplifier bad caps

If you are convinced it is caps, the larger ones are the more likely candidates. However, you are going to have to remove the circuit board to get to them as there is likely a solder connection on the other side of the board.

That means moving and/or disconnecting other wires. That photo also shows pretty tight construction quarters so you will need to be very careful with your soldering. You wouldn't want to short a trace or heat damage a sensistive component.

There are also other factors that can cause problems. You could end up replacing caps and not fix the problem. The best advice is to get a service manual and trace through the circuitry with the appropriate test equipment and precisely locate the problem.

Professional shops may not work for free, but they should know what they are doing. Good luck if you decide to undertake this yourself.

I think your better off finding a qualified tech and have him troubleshoot the problem. All of the caps? that seems unlikely as the unit looks to be fairly new. Even at 40 to 50 dollars an hour I doubt the bill would be more than $200-300.

my experience has been that when filter caps get old you will hear more 60hz hum or buzz from the speaker. the problem you describe does not sound like a bad cap. It does sound like an issue with the power supply however. I agree with the others. Get an estimate with a qualified tech.

My guess is that the caps are fine. One of the switches on the front is the likely culprit. Move the switches back and forth and see if the sound crackles. If you find the one, use a cleaner like Rat Shack zero residue cleaner or a Caig product, or CRC. This should do it. Caps do not go bad often. If they go bad, they usually leak a yellow hard goo on the board. Replace quickly. This is an acid and will ruiin the board over time.

Hmm...now I'm second guessing. A lot of uncertainty as I've been told it's definitely the filter caps. However, the amp is not even 10 years old and I've been suspicious of this assessment. I've seen what cap leakage looks like and they definitely look fine.

I'll try and explain the problem in more detail. Upon startup, the "bacon frying" sound gradually builds and becomes constant once the tubes are lit. The power tubes flicker with every pop and crack. This symptom used to be only in the right channel and now it's in both. As indicated, I've swapped all of the tubes with new ones. I'm afraid I've probably ruined the new tubes because of this.

I purchased this amp used from a local hifi company that is out of business now. I live in a small city so finding a tech that specializes in tube amps will be difficult. Are there any fellow Canucks out there that know of a tech near Regina? As a last resort, I may end up contacting the UK manufacturer and seeing what can be done.

Thanks guys for your help.