SET vs OTL

Agree with Paul. The 45 is the triode gold standard.

Followed closely by 50, 2A3, and PX-25.

The 300B is a distant fourth and IMO, highly overrated.

I agree with Bill's ordering of the triodes except that I've never heard a 50.

300B can be done well (I learned recently I really like the JE Labs 76/6SN7/300B circuit) but bad implementations outnumber the good, it seems! The thickened midbass and blunted transients is a show-stopping for me.

I'd also throw the PX-4 in there either before or after the the -25. I had a Kurashima PX-4 - amazing amp.

People always talk about how much difference the circuit, driver, power supply, and output tranny make, yes the various tubes almost always retain their basic sonic character no matter what the amp IME.

However, I've heard those Wyetechs really break the 300B mold. I've also heard that about the Welborne DRD circuit.

As for volume and dynamics, yes, for a 45, you need a back horn, front horn setup, or highly efficient widebander on OB. But it's amazing how dynamic the good SETs are within their capabilities.

Any decent 300B SET will drive 90 dB/W dynamic speakers that are a fairly easy load very well. I'm thinking DeVore, Green Mountain.. lots of others.

Its the amp design,construction as much as the output tube thats responcible for sound quality. Having owned over 10 -45 SET. Probly arround 25 others SET many OTL SS PP etc. I can say that I did not find 45-50 SET to be the best in anyway. I look at total design not just tubes used and make dam sure it matchs loudspeakers or you SET yourself up for falure which is what most 45 2a3 owners do. Wavac, MasterSound, PAD, John Hogan have owned these 300b amps and they sounded much better than my 45 SETs and I have owned most of the great 45 SET amps that get raved about. With SET match your loudspeakers to amp or forget about it. Would say the same about OTL designs.

I can't argue with any of the above as I've never heard any amps built around those output tubes. I've always been concerned about speaker matches - as per Atmasphere's observation. Personally, I love most of the 300B designs I've heard and some of the best sound (though maybe not best deep bass) I've achieved came from 300Bs with slightly lean speakers

The original Merlin VSM SE with the Carys was a great match. I remember having a turntable set-up guy -from a very, very high end dealer that carried only SS electronics at the time - install a new arm. When he was done and we listened to the system, his eyebrows literally
arched up. He was stunned.

My point is that a good 300B set up with appropriate speakers can be very satisfying. Strictly neutral sounding amps have never IMHO been any guarantee of good sound. The right amp with the right speaker has always been the trick for me. After reading these comments, I'm sure I'll check out some of the lower power SETs you guys are so enthused over.

Marty

Given a speaker can be driven by an SET amp of comparable build quality/design the 45, 50, 2A3, and PX-25 will outperform a 300B all day long, due mostly to superior linearity. Don't even mention the 845 and 211.

I've heard a boatload of these amps with appropriate speakers and I stand by my previous post.