6550 tubes
 

I have a svt-cl with a bad power tube and I'm looking to replace but I know I need at least three matching tubes, is it safe to have to two separate brand of power tubes? I want to order three matched tungsols and have three working sovteks in it.

Should be fine.

Ya, the bias controls work on 3 tubes each, so it really doesn't matter what kind you use since each triplet set has its own bias.

Why not order the Sovteks? Each brand has a slightly different voice that could or could not throw off critical listening.
You are changing a complete push or pull side.

I'd stick with the Sovteks ... it's the stock tube and it's really a good tube and you'll save some $$$$

well
 

I usually read the matching figures on the bottom of the tube left by the supplier who last supplied the matched? set of sovtek's and replace only those tubes that are damaged in some way from the same people who wrote the quiescent current figures on the when they matched them originally.:bassist:
PS Check your work with bias probes to see if any have drifted.