Upgrade capacitors in tube amplifier?

I have upgraded crossovers with very good results.  I now have a "very good" IMO chinese tube amplifier that can probably be improved with a couple of capacitor upgrades.  

I don't have a schematic, but I have a picture and I expect some of you knowledgeable folks can point me to/confirm the ones to change.  My thought is to change the two large silver ones first and then maybe the four smaller silver ones (on the circuit boards). 

Would probably replace with something like Jantzen Superior Z-Cap or comparable and go with a higher voltage if space permits.  




Showing 2 responses by atmasphere

I'd be careful about anything that is paper and oil in a tube circuit. Over time its not that unusual for them to develop a bit of electrical leakage; this can throw off the bias and operating points in the circuit.

FWIW we've had good luck with the V-Cap ODAM series in amps like this. That part also appears to have an oil component, but it doesn't appear to have a paper component. At any rate they sound pretty nice and we've not had any problems with them.
There are three coupling caps. The first is at the top of the photo, one in each channel. To the far left and right beside the power tubes is a small circuit board; the coupling caps for the output tubes are mounted on that circuit board; they should be matched for best results.