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Tube Single Ended Triode Questions??

Why can't SETs be built with more power and able to drive a bigger range of speakers? I know the 300B tube can goto 10 Watts or so, and the 2A3 in only 2W, but why can't they do an amp that is like "single ended parallel" with several amp stages in parallel? Or, why can't tubes be used like EL34, 6550 and KT88s (I guess these are known as power tetrodes) and make higher power SE amps? I guess the idea behind SETs is to avoid splitting the siginal into push-pull and they are class A, but you give up a little S/N ratio with a SE circuit - is this correct? Are some tubes too noisy to run single ended, or can only a portion of a KT88 be used in SE mode?

Also, the output transformers- is this really what seperates okay from great SETs? Are quality transformers what makes them so expensive for what appears to be a very small parts count?

I have some question for latter about SE -vs- Balanced preamps too - is it a simialar trade off to SE/BAL amps, but I will save that for latter.
6550c

Showing 2 responses by rrog

rrog
1,958 posts
 
SET amplifiers with more power been have produced by Cary and VAC using the exact method you mentioned. By running the tubes in parallel. Vaic/KR have produced tubes with more power and I believe there have been some KR amplifiers with higher power ratings also like around 40 to 50 watts.

Manufacturers of SET amplifiers have told me the transfomer is most important.
rrog
1,958 posts
 
Mastersound, the first company to build an amplifier based on the Vaic tube, makes a parallel single ended amplifier with KT88 tubes producing 30 watts per channel and another parallel single ended amplifier using EL34 tubes producing 20 watts per channel.
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