Recommend me a good but cheap variac suitable for tube amps.

jtcnj said:

https://www.amazon.com/PHC-Enterpri…ie=UTF8&qid=1499956900&sr=8-4&keywords=variac

This looks like the same one above, and the one Parts Express has for a little less $ shipped:

Click to expand…

I’ve been idly browsing for one lately too. That one is only rated to 3 amps and my impression is that you want to have one rated a good bit above what you are planning to use it on, I was thinking a minimum of a 5 amp unit for tube amps, maybe even a 10 amp. Also check to see if it is isolated or not. Most aren’t but one of the brands on amazon in that price range does make isolated variacs, though I think they are maybe about twice as expensive as the one you listed. I’m not really sure how desirable that feature is for our purposes, but remember reading somewhere that it is something you want for certain tasks when using an oscilloscope… which is a subject I need to learn more about, so maybe someone else can comment on that.

I’ve been idly browsing for one lately too. That one is only rated to 3 amps and my impression is that you want to have one rated a good bit above what you are planning to use it on, I was thinking a minimum of a 5 amp unit for tube amps, maybe even a 10 amp. Also check to see if it is isolated or not. Most aren’t but one of the brands on amazon in that price range does make isolated variacs, though I think they are maybe about twice as expensive as the one you listed. I’m not really sure how desirable that feature is for our purposes, but remember reading somewhere that it is something you want for certain tasks when using an oscilloscope… which is a subject I need to learn more about, so maybe someone else can comment on that.