[Yoda]

What is the expected tube life in the Cornet2?  I put in a mullard 12au7 3 weeks ago, and it is showing a bit of brown burning on the top already.  Does this affect performance?  Perhaps I'm running a bit hot?

Other tubes 2 Sovtek 12ax7lps, Mazda 5y3GT
 
Matt

[GRD]

I haven't used up a tube yet so I can't give an estimate on expected tube life.  I hear small signal tubes can last a long time - like several thousand hours.  The AU7 runs quite warm and I have seen the getter coating change a little on one new tube after a couple of weeks of use.  But the tube itself is still O.K.   The getter was just doing it's job.

[hagtech]

It all depends on the tube.  All circuit operating paramters are within limits, nothing extraordinary.  A good tube will probably run for 5k or 10k hours.  And they die slowly, so some could hang on for even longer.  I have no doubt a quality NOS from 50 years ago will outlast anything today.

You could double check voltages, make sure heater and plate are reasonable.  A color change could indicate gas or contamination, or perhaps nothing.  A dying tube will start to roll off the high end and sound thin, loss of dynamics.  Maybe even snap crackle and pop.

jh

[bluesky]

Hi Yoda

Just out of interest here is an Australian site that states some interesting things about cryoed tubes, they also have some apparently rare tubes.  I don't have ANY experience with tubes at all, I just found it very interesting and it may be of some help to people who would like to try it, me included, but it is out of my price range.......to be honest just about everything is out of my price range as I'm on a pension.

By the way Jim, I have tried a couple of places for decals with no luck so far.  I'll let you know if I have any success with trying to source them.

Cheers

Ian

[bluesky]

er.............

and here is the website  www.cryomusicsystems.com

Ian