Why no threads on OTL amps?


I looked through the old thread list and didn't find anything on OTL amps. How come? Does nobody like them? Is there something wrong with them? Would you buy/notbuy one, and why? If you would buy one, which one do you like best? I always thought OTL was the best, but there doesn't seem to be much interest here on this forum for them.
twl
My reading of the schematic on the Berning patent shows no "output transformer." There is a coupling transformer for the RF carrier network that which is what actually performs the impedance matching function. Since this coupling transormer does not perform the function of "output transformer", with the attendant sonic weaknesses(ie phase shift, saturation, and HF rolloff), it cannot correctly be termed as one. So, if you want to nit-pick, here's a nit-pick in return. I will allow that the Berning could not be termed "total transformerless" but OTL does apply for the above stated reasons. The Zero Hysteresis moniker could not be applied if this amp had an output transformer. If you look at the square-wave response on an oscilloscope(as shown in Berning's "white paper") you can easily see the difference. No ouput transformer could behave like this. Perhaps you have been talking to Jennifer Crock, as she has been referred to in an article as saying the Berning is not OTL. I will not speculate on her reasons for saying this, but her misunderstanding of the circuit is not Berning's concern. He makes amps. So, yes it is OTL, no it is not TTL, it is radically creative and brilliant, and it sounds great. No knock on any other great OTLs out there, just my meager expanation on a minor technicality that I wanted to address about the OTL designation.
I say to-MAY-to, you say to-MAH-to. Every time there's a discussion of OTL amps and the Berning comes up, the thread eventually evolves into a debate (to put it politely) over whether the Berning is 'really' an OTL. Who cares? Obviously, some people do, or the issue would never arise. But why SHOULD anybody care? Isn't the issue whether the amplifier, OTL or not, does its job well--namely, accurately amplifying an audio signal? What additional value--financial, 'bragging rights', whatever- would a Berning amp gain from being a 'true' OTL, or lose from NOT being a true 'OTL'? "A rose by any other name would still smell as sweet", said some famous poet.
By the way, I own a Berning 270, and love it with my Merlin Milleniums, whether it's an OTL or not.
Jtinn, just for the record it is not my goal to invalidate your comments entirely and perhaps my statement of being "quite closed minded" was going a bit far. My intent is not to create personal conflict in this forum, as I do not feel its necessary in order to make a point. Everyone is entitled to their own opinions and interpretation of the design in question. Like many around here often state, "let your own ears decide".

Best Regards,
Chris

So let me understand. The idea of a OTL amp is that there is no transformer between the tubes and the speakers, right? So, here we have a transformer that's not a transformer because we don't want it to be a transformer, so the amp is OTL because we want it to be an OTL and be included in that class of amps.

Other than a desire to argue, what's the point of the debate?

Best wishes,

Bill E.
Owner of Tenor's
Without trying to be argumentative, I agree that if one wants to call the amp non-OTL because of the "coupling transformer", this gives one an ostensibly good reason. On the other hand if one wants to call it an OTL, one can use my reasoning in the above post. I've already posted my reasons. I think that the main point is that it addresses the inherent difficulties in circlotronic OTL circuits, without resorting to a "conventional"(is that alright?) output transformer for impedance matching. Does so with considerably fewer tubes, with lower heat, lower energy consumption, and excellent reliability. I mean absolutely no disrespect to the Tenor people, Atma-Sphere people, Graaf, or anyone else. So now there is a design that provides(apparently arguably) the benefits of both OTL and traditional output transformer amps with neither of their typical weaknesses(although not perfect). I say that this can only be considered a historic event, much like the circlotron before it. Regardless of how one categorizes it, as several mentioned above, it exists and cannot be ignored. How it will fare in the marketplace is up to the performance level that users feel it posesses, at the various price points. Just like any other product.