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Help on tube question

Is it possible to replace a bad kt88 tube with a 6550c tube and do no damage? The VAC 160i uses 4 KT88's and with one of the tube bad, I have lost one side of sound. If it were ok to use the 6550c's, I could replace the 4 KT88's or just one. I know Monday I will get help from VAC. But, I just want to hear that sound again if I could and do no damage.
Thanks for any information or Opinions. Tra
tradubois
rodman99999
6,206 posts
 
The Classic 60 was designed for four matched pairs of 6550s. It's no surprise that they worked better in the amp than KT88s.
bjesien
1,372 posts
 
Don't mix them. Bad circuit leads to more trouble.
atmasphere's avatar
atmasphere
12,085 posts
 
The 6550 and KT-88 are nearly the same tube. They have similar bias points and the like, the big difference being that KT-88s are supposed to be more linear ('KT' refers to 'kinkless tetrode' IOW there is no kink in the linearity curve like a 6550 has).

So you can kinda sorta mix them, but the 6550 should be matched to one of the KT-88s and that seems unlikely. If you have individual bias controls that helps- then the only issue will be that distortion will be higher in the channel with the 6550. You may not hear it though...
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