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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
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.
sebrof's avatar
sebrof
837 posts
 
Besides the amp configurations that Rrog mentioned, there are others that use Pentodes and Tetrodes. I have single ended amps that use EL84, EL34, 6L6, KT88, 6550, 807. They range in power from 2 watts to 8 watts.
rockadanny
1,228 posts
 
My monoblocks are 45 watt SET. Designer/ builder states really more like 50 watts, with peaks to 90 watts. Speakers are 87dB, min. 6 ohms. Plenty-o-power. As stated above, parallel (6C33C) tubes per monoblock.
sounds_real_audio
1,019 posts
 
I have been a dealer for the deHavilland GM-70's for about 6 years and they have the power to drive real world speakers with crazy good sound. Not hyper priced either.

Check out their website dehavillandhifi.com
onemug
784 posts
 
I use a pair of SET Cary 805AE's to drive my Maggie 3.6's occasionally. Cary claims either 50 or 70 wpc, depending whether you use the 845 or 211 output tube (1 tube per channel, no paralleling). I do 90% of my listening at low to mid volume levels and normally use Pass XA monos to drive them but I love the sound of SET's and took a chance on the Cary's working out. They do to my satisfaction.

I seem to remember ASL making a single ended KT88 amp some time ago. I think it only put out 12 or 15 watts though.
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