The best coupling caps in power amp ?? Mundorf, Infinicap ??

We've been auditioning coupling capacitors for close to 40 years now. The current king is the V-Cap copper foil Teflon; it is both neutral and extremely musical.

As far as musical goes we've heard some extremely good paper and oil types but the problem we've seen with many of them is that they can develop electrical leakage. Usually this is a very small value, but when you are using the coupling cap in a power amplifier section the effects on the bias on the power tubes should be considered!

For this reason I don't regard such caps as in the running as some power tubes can be quite rare (not to mention some vintage power transformers in some vintage amps) and such parts could shorten the life of both.  So I see the V-Caps as being the only game in town.

Now one important issue with the V-Caps is that being made of Teflon they should be handled as little as possible. For this reason they are shipped in bubble wrap and they really should not be unwrapped until installation. Otherwise the handling will cause them to change value and by this I mean loose value. I don't doubt that this issue alone could be the reason why the well-deserved accolades this part gets are not universal. But that's how it is with Teflon caps.

@atmasphere

So you mean the caps are easy to mechanically deform? For instance, squeezing them along the length?

Never handled a cap that delicate!

E

No; but if you've handled a Teflon cap, then unless it was hermetically sealed you probably changed its value. You won't see much in the way of physical deformation though.

I've never seen any film cap that wasn't hermetically sealed. This is very weird.

I mean, if not sealed, then really any change in atmospheric pressure or humidity could change it's value over time.

I have been in touch with Chris over at V-Cap and it seems I am somewhat corrected. Turns out hermetically sealed caps are more rare than I thought, but that still doesn't make them subject to atmospheric effects like I had surmised.

I hope he will post here shortly.

Best,

E