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Why not more on 845 SETs?

As a brand-new owner of a Bel Canto SETi40 int amp,(bought used) I was intrigued to see very little in the fora on the subject of 845 SET amps an A'gon. It seems that this provides the best of both worlds -adequate power to drive most moderately sensitive speakers- 40 Class A SET WPC with SET sound. What is the downside to this approach and why don't more of the SET groupies have higher powered amps, giving them much more latitude in speaker selection? I drive 4 ohm 87 db sensitivity Totem 1 Signatures quite adequately with this amp. Is it beacuse of transformer issues, difficulty in finding adequate designs, size or the feeling that this is not a true "SET sound"?
I would like to hear SET-owners' reasons, if possible.
springbok10

Showing 3 responses by c123666

c123666
871 posts
 
Without first class transformers it won't matter how "good" the output tubes are. A well designed interstage coupled 300b or 211 SET amp sounds so much better than the capacitor coupled amps I've listened to I am sold on interstage tranny coupling.

The 300b SET interstage coupled amp being put together for me right now is so much better than my prior Audio Note Conqueror it is silly; another world. Parts cost on a four chassis 300b SET IS coupled is very expensive between 2000 and 4000 depending on transformers used (silver wound interstage run the price up about 2000).
c123666
871 posts
 
And transformer prices are going up as is anything made out of metal....Price a set of six transformers from Electraprint, or Lundahl, for a single ended interstage coupled amp, then figure in the cost of a truly inert/non resonant chassis and the other parts and you'll quickly see why most quality 300b amps start around 4000 to the sky.
c123666
871 posts
 
The 845 simply does not sound as good as a top notch SET 300b amplifier. In addition, if you want the best performance from 845 designs NOS tubes would be useful; they are priced at something like 1000/pr last time I looked? Sure, the manufacturers will tell you their design is optimized for the chinese tubes; the NOS will sound better but at a huge cost.

A 300b push/pull interstage coupled amplifier with top quality parts will make 16 to 20 watts and sound damn close to a well executed 300b SET. Main reason more 300b push/pulls are not sold is they are quite a bit more expensive. More power means bigger transformers; push/pull means more parts and more contruction time required (and a bigger chassis, usually) to put the push/pull together. More capacitors, resistors, wiring, twice as many 300b tubes (which raises cost anywhere from 200 to 2000 over a SET design depending on tube selection).

I would rather have a well designed 211 based push/pull amp that will run into class A2 and make a LOT of power. Or, a single ended 211 that will make in the mid 20s of power when pushed into class A2. The 845 cannot be driven into Class A2 is my understanding. The 211 is the tube that Mr Kondo selected for his original Ongaku amplifier in the late 80s.
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