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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
dopogue
1,773 posts
 
Beats me. I have a pair of 845 SET monoblocks, designed and built by a friend, that will drive my Gallo Reference 3s to really stentorian volume levels. They replaced 140 wpc Conrad Johnson Premier 12s in my system because they simply blew away the CJs, which are certainly not bad amps. Dave
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.
fatparrot
1,314 posts
 
C123666, what is class A2 operation?
dopogue
1,773 posts
 
Whoa there. Some of us like the sound of 845 SETs better than the 300Bs. In my case in a three-way comparison in my system between the CJ 12s, a modern SET 300B stereo amp, and the 845 SETs, the 845 was the clear SONIC winner. I know, YMMV and all that, but I've never heard a 300B amp -- not yet anyway -- that can compete with my amps. And certainly not a PP version.

The new 845B and 845M (I haven't heard these yet) tubes from SuperTNT are rewriting the book on what can be expected from new-production versions of these tubes. The 845Bs are $150/pr. There is absolutely no reason to invest in NOS 845s, IMHO. And even the best current production 845s are dirt cheap compared to 300Bs.
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