New Tubes- Need Burn-In?

I've been very happy with the SED flying "C" EL34's in my Dynaco MkIV amps. I also loned a spare quad to a friend with Antique Sound Labs amps which he will be keeping.

Bartokfan...KT-88's and KT-90's are two very different tubes. Compare the KT-88 with the winged C 6550 insted. KT-90's to my ear are much more punchy and a bit more agressive then the winged C 6550. Usually KT-90's have a bit more output as well. What was the tube your Jadis amps were 'voiced' with? BTW as far as I know Jadis does not make their own tubes and buys them from China, Russia, Yugo. etc. G.Garfield

The real term is aging, yes then the cathode emission becomes stable and the tube does not drift. The recommended time is circa 36 hours.Me, vacuum tube gear, late 1950's, Stategic Air Command. Delt with tubes. i'm thinking of doing a online consulting service, does this sound like a good idea, to all? won't be free, but i'll teach audio also to component level including transformers.

I am considering tube swapping on my Cayin as a necessity. For the last couple of days I have been hearing some loud pops in the right channel during the first ten minutes of warmup. After that the unit appears to be fine. I have never attempted biasing and tube swapping before but I am eager to learn. Dan thanks for e-mailing me the biasing info.

Change the small tubes from the right channel to the left channel and vis a versa. If the popping changes channels you've sourced your problem and potential solution. IME your complaint is typical of small tube deterioration. If that doesn't work change the power tubes in the same manner - if they were matched, biasing for this simple change may not be necessary. If you have to replace one or a pair you will then need to re-bias the new tube(s).