SET vs OTL

I have never encountered a SET amp that even came close to an OTL when using an OTL friendly speaker. The difference is startling. I find this true of P.P. designs as well. 

Well actually no! True the quality of the iron as well as the circuit and its design do contribute and can make significant improvement in any amp design, the absence of a transformer contributes hugely to the intrinsic difference in sound. Provided that the amplifier requirements are met, I think an OTL is a superior design. 

Antigrunge,
What speaker were you using for this comparison? 

Phantom a/v is correct in that impedance is crucial with OTLs which can be a serious impediment. Your experience mirrors mine. What amazed me was how quickly the SETs we used in the comparisons went into soft clipping. They got more muscular but confused sounding. It took hours of listening and direct comparison to figure this out. 

For the record I have heard Atma-sphere, Joule Electra, Berning quasi-OTLs, the older Tenor, Transcendent Sound and Einstein. 

I also have auditioned/owned several P.P. designs from Thor Audio, VTL, EAR, VAC, French company I cant remember that was famous for CD players and SETs using 845s, 2A3s, 45 and 300Bs. Granted no SET design that was over $ 20K. 

I believe that each type of amp share many similar sonic characteristics. But removing the transformer is always a plus if you can feed the amp its entre of choice. 

The best SET amp I have heard was an old Mastersound made 32B integrated amp running only an an amplifier.

I know the Duevel line fairly well. What I would like to know is how low the impedance actually goes and with what type of swing. I agree that using an auto-former somewhat defeats the purpose of an OTL and would not be an option for me.

Thanks it was Audioaero. This was a good P.P. amp. that was flexible on which power tubes were used. I think I ended up using some old stock  6550s. This amp used 6SN7s as drivers and I was smitten by the Tung-Sol round plates in this application. Using P.P or S.S. designs sure makes life easier in many ways. 

Oh and so you know, much of the auditioning of amps was done on a pair of DeVore 0/96s which responded very well to changes in amplification. A speaker which is better than the sum of its parts and I mean this in a very positive way, although this was not my personal speaker. 

What Atmasphere is exactly what we experienced in our comparisons. Takes a bit of time to figure this out, but all 5 of the participants eventually came to the same conclusion. 2 of us heard this within moments.