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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
jond's avatar
jond
5,660 posts
 
normie what speakers are you going to be driving? I assumed your question was more theoretical but looks like you're in the market for a new amp. So the more info you can share about your system the better.
normie57 OP
50 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!


knghifi
1,668 posts
 
@normie57, I heard Kevin announced a VAC Ren 5 SE upgrade.  If anything like my SigMKIIa SE upgrade, Jump at it now!!!  Call Kevin ASAP!!! ... (Sorry, ebm took my keyboard).   Improvements are staggering in all areas.

I highly recommend the VAC Sig 200 IQ.   It's probably one of the most owner friendly tube amps.  Auto bias, if power tube arc, IQ trips and just replace the tube.   You can roll KT88, KT120 or KT150 if need more power or linear sound.   For even more power, buy a 2nd run in mono.   But most importantly is VAC SQ has improved, more transparency, lower noise ...

Now that's REAL creative and outside-the-box thinking!  Not just a bunch of Blab Blab ... look at me, I'm the best ... hot air.
normie57 OP
50 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?

tbanis
12 posts
 
Hi all !
Class A, AB etc. But I also noticed that there are output transformerless KT88 systems. I believe its a so called cathodefollower?.
Then again comparisons with SS amps is difficult.... Tube amps are voltage related instead of SS which are current related.
Another thing.... output transformers have a specific habit. So quality of these is realy important and will take a prominent place in the pricetag..
But most important: the fun you get from your equipment!
regards
Ton
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