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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

Showing 5 responses by normie57

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!


normie57 OP
33 posts
 
Thank you all for your input!  Agreed....many roads to Rome or great sound.
I'm considering a VAC Sig 200 IQ stereo unit using a total of 4 KT88 delivering100 Wpc in class AB1 or AB2, or a Zeso Bia 120 stereo unit, also using 4 KT88, delivering 60 class A Wpc.  Both are in the $12,500 to 14,000 range.
Your thoughts and preferences would again be appreciated.  
normie57 OP
33 posts
 
Thanks knghifi!
I appreciate your recommendations on the the Sig 200 IQ and the Ren V SE upgrade.
You are so right. VAC is a proven winner for two decades and Kevin is great to work with!  Why stray?

normie57 OP
33 posts
 
Thanks Charles and jond:  I will be driving KEF Ref 3 loudspeakers. My preamplifier is VAC Ren 5 and my room is very modest at 14 x 16 ft.  I'm tempted to go Zesto Bia 120, albeit less power, as class A and running tubes conservatively sounds enticing.  However I know VAC is synonymous with great sound. I owned a VAC Phi 70 a decade ago but that was a much different 300B beast.  Both the VAC Signature 200 IQ and Zesto Bia 120 have transformer coupled balanced inputs.  Thanks!


normie57 OP
33 posts
 
I would still love to know how VAC gets 100 watts per pair of KT88s without tube reliability issues or distortion. Probably some proprietary secrets, the intelligent auto bias,  as well as huge power supplies to comfortably generate the needed plate voltages.  I have heard Kevin use The Signature 200 IQ in monoblock configuration at a couple of shows and the sound was memorable.  I'll place an order and give them a spin in stereo first.  I would also love to hear from Zesto amplifier owners, either the Bia 120 or Eros 300.  Thanks so much!
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