Which Valve Question

asimmd

Further to my questions regarding the Vox AC15 C1, I read somewhere the first thing to do is swop the valves. My question is,does the type of valve matter as long as it's the same type. If so what difference will swopping them make. And which valves would be considered the best.

ecc83

For output valves I think JJs get a pretty universal thumbs up?

I have been told the very latest TAD stock is very good.

Pre amp valves seem a bit subjective but for value and reliability I have always found the TAD 7025 hard to beat.

Others will have their opinions of course.

Dave.

ICBM

Unless you want to buy some vintage Mullards or something, don't bother swapping the valves. The ones they come with are fine. Conversely if you *do* want to swap the valves, I wouldn't bother with anything new-production… if you see what I mean .

If you need to replace valves because one has failed, then it's more of an open question…

In an AC15 you can use any valve of the same type, since they're cathode (self) biasing - but be careful with Russian-made 12AX7s in the middle preamp valve position, since they have a relatively high failure rate. This is why Vox ship the amps with Tung-Sol 'reissues' (which are Russian, and sound good) in V1 and V3, but a standard Chinese 12AX7 in V2.

asimmd

Thanks both for the input. I will leave them as is and see how the amp performs.

thermionic

I swapped a few modern production ECC83s in my AC15TB2 a couple of years ago (V1, V2 & PI) and I couldn't hear any difference.