2. amps-preamps
  3. 154865-976

New tubes...far more power??

I replaced my quad set of KT150's in my tube mono blocks a few days ago...replaced with a new set of KT150's that were quad balanced and now for some reason the power output is considerably more. So much so that i need to drop the volume control on my preamp by three notches! Plus, the sound quality is actually no better than before...and maybe even a little strident! Anyone have any idea as to why this would be? 
128x128daveyf
dweller's avatar
dweller
3,779 posts
 
Does your amp have auto-bias? If so, you may have to reset and bias to spec for new tubes. The auto-bias then maintains as needed. Check your manual.
daveyf's avatar
daveyf OP
2,857 posts
 
@dweller   My amps are auto biasing, but they have no method to manual bias, I don’t know any auto bias amps that do.
dweller's avatar
dweller
3,779 posts
 
If the manual doesn't cover this, I'd contact the maker. Regards
daveyf's avatar
daveyf OP
2,857 posts
 
This amp design doesn't allow for manual biasing. As I said before, I don't know of any auto basing designs that allow for manual biasing..do you??
roberjerman
4,319 posts
 
All tubes, both large and small, produce varying amounts of harmonic distortion: 2nd, 3rd, 4th, 5th ... And this is measurable. Your new set probably has a different harmonic distortion signature. Which you noticed and did not like! There is no "cure" for this! Just accept it - or buy a set from a different manufacturer. And hope that they will have more pleasing sound! 
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