What's Your Approach for Testing Tubes?

[stelligan]

My choices, as of today...

Selected JJ for PI
Selected EH for V1, V2 a


Gary

Exactly where 2 of my amps landed. I did not, however evaluate voltages on both sides of PI. Just going on my ears.

[Funkalicousgroove]

FWIW, I didn't pay $1200 for my VTV, I just watched Ebay for a while. since it's not a High Demand Item I got it for $600, and find that it's paid for itself twice over since I've had it!

[phsyconoodler]

I use a nice single ended amp as a testbed for tubes.This amp which is basically a high powered champ,is very sensitive to tube changes.I test all
my preamp tubes in that amp and it has been doing it for me for years.
I also measure the current on the power tubes because it is fixed bias.I match the tubes in that amp and it has been transferable to my push-pull amps.
Of couse I always recheck them in the amp the tubes end up going into,but it has been an infallible 'tester' so far.

[Structo]

Interesting takes on testing vacuum tubes.
I recently got back into tube amps after a hiatus of many years (life, family, job, etc.) and was wondering what your experiences showed with the PI or driver tube in a tube amp?
Do different tubes in this spot affect tone other than having mismatched triodes (unbalanced) affecting the performance.
Can different (brands) tubes in the PI socket change the overall tone in an amp?

[phsyconoodler]

The PI tube can have a quite an affect on the tone.That's why some guys buy matched triode tubes and others install a PI trimmer pot.The trimmer pot is a good way to test your theory's about the PI being balanced or unbalanced.

[weld]

The trimmer pot is a good way to test your theory's about the PI being balanced or unbalanced.

interesting...

How could I Try This...