Do new tubes undergo break-in like other devices?


I just put a new pair of Mullard Ecc34 (should be 6sn7s) tubes in the r/l inputs on my BAT VK60. These are the 2 most importants positions for BAT amps.

Part of it sounds wonderful...back of the soundstage, instrument separation, dynamics, articulation in the bass. Oh, and much queiter.

However, I don't think they have as much gain, I have to turn up the volume some on the preamp, and the bass is much lower vs the other parts. Kind of like a new power cord...needs time to open up. I can deal with the gain, not sure about the bass. This may just be a system matching thing, works great for some, not for me.

Is it break-in related?
128x128jfrech
Can be, I know I would give 50/100hrs burn in time before I would really find fault here. Then it could be matching. I assume you have checked bias( I am not all that familiar with how to set up a BAT) as it could have changed. That being said, I know I can change the sound of my tube devices by changing out a couple of tubes. Like most things, it part of the reason that there are so amny out there.
Yes. Tubes do burn in. We find anywhere from 25-100 hours depending on the type of tube and the equipment used. Some gear draws a lot more current which tends to break them in quicker than low voltage devices.
the vast part of break-in process of the new tubes is when you idle them for almost two hours with no input signal. the second and further times you will have to follow the instructions suggested by manufacturer on how long you should worm-up the tubes before you listen. the rest will come with time. i might mistake to say that it's more matter of personal adaptation rather than some physical electronic process takes place, but imho i can't find any other explaination.
Jfrech, did you change from well used Russian tubes?

If so, consider two points. The Russian tube had poor highs when new and undoubtedly got worse as it aged. Second, the bass on Sovteks (if that's what it was) are "bumpy" in the bass.

Comments already posted about tube break-in are accurate in my experience. If you are still dissatisfied after your gear has settled in, post back here.
Man!!!! I asked the same question and got different answers!!!!

I recommend that you listen like crazy for the rest of your life. You lose your hearing by the day, anyway. Worry about there not being enough broken-in musicians.

Brad Day
Atlanta, GA