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How do tube manufacturers like VAC get 55 watts per KT88 where others get only 30-35?

Just wondering how some push pull tube manufacturers like VAC and others get 55 watts per KT88 tube while others are more in the range of 35? Does driving a tube hard like this have any ramifications as to distortion, sound, headroom and tube life? I know VAC amps are highly musical so design, power supply and output transformers obviously contribute much to overall sonics. A company like Zesto gets about 25 watts per KT88 but uses a class A push pull circuit rather than class AB.  This seems like an attractive design.
I guess, as always, it's all in the implementation. Thank you for helping me to better understand.

normie57
bdp24's avatar
bdp24
4,908 posts
 
That’s nothin’! Roger Modjeski gets a hundred watts out of a pair of KT88’s in his Music Reference RM-200 MK.2, and without running the tubes hot. How? Creative, outside-the-box thinking. He discusses the amp's design in his now-dormant AudioCircle Forum.
normie57 OP
33 posts
 
Thanks bdp24. That's similar in that VAC gets 450 watts per Statement 450 Monoblocks with only 8 KT88s per side.
Like you say...implementation and out of the box thinking...and very special designers in Modjeski and Hayes!


mechans
2,999 posts
 

My Jadis DA-60 gets only 60 watts out of 4 KT -88s per side, in case your counting that's 15 per tube.  In  class A, push parallel  pull pairs, if I recall correctly. They could be understating the true output in addition you can use different output tubes in this amp.

I think the output transformers playing role in shaping the sound of most tube amps.

bdp24's avatar
bdp24
4,908 posts
 

Definitely mechans. Modjeski offers ot that he hand winds himself as a thousand dollar option in the RM-200T, but the standard ones in the non-T version of the RM-200 Mk.2 are real good, custom built for him to his specs.

Dang Normie, that's a lotta tube power! Just think---Kevin Hayes makes 450 watts with 8 tubes, yet the Atma-Sphere M-60 also uses 8 tubes to create only 60 watts. But then it doesn't have output transformers, which is even better than really good ones!

mid40sguy's avatar
mid40sguy
116 posts
 
Kevin Hayes of VAC has stated in part it's due to the output transformer design. Lovely sound that's a fact.

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