KT 88's....what's the story????

I think that all power tubes can die of sudden unexpected death (you hear a pop - then no sound - you replace the fuse and the tube, sometimes you find you have also blown a grid resistor and need to get it replaced) as opposed to normal death which is quiet and fixed by simply replacing the tube. Some tubes are more rugged and less subject to the sudden death syndrome. That is one of the main reasons tube amp manufacturers require that you use the tubes they supply to keep they warranty in effect - because they are less prone to sudden failure, not that they necesarily sound better.

Thanks all....Audioman4.......can you substitute a KT90 for a KT88?? Doesn't that void the warranty?

Although the vaunted kinkless tetrodes are wonderfull tubes I would disagree with the above. I have seen tubes that have glowed cherry red and eventually melted the glass envelope. This is not at all common, but is a distinct possibility.

You might want to check out the review of the Hurricane in the latest issue (Feb/Mar) of TAS before trying different tubes -- even though they "lost" a few tubes, they had high praise for the "sound" of the stock Chinese KT-88s (see p93)

Regarding the Warranty...
You know, I never really gave it much thought...
There really isnt too much in an amp that can "break"
Not any moving parts...
I have been running kt 90 tubes in the Sonic Frontiers for
a while and there have been no problems at all..
If you are concerned, contact your manufacturer and get
their warranty information clear.
Good Luck,
Joe
Custom Audio LLC