Thought on OTL tube amps

Maybe the acronym OTL should be changed as applied to David Berning's ZOTL amplifiers as the original ILOT design, iron less output transformer.It never ceases to amaze how this topic is continually debated after all these years. Al you REALLY need to check the archives, if you haven't already, I'm sure you'll find it quite interesting particularly the thread where Ralph and David have a lively discussion of this topic, I think you'll enjoy!

I'm not too sure David EVER called it an OTL, I believe it was Harry "Gizmo" Rosenberg that first did but I may be mistaken. One thing for sure after it was forevermore designated OTL by some, it was equally or more declared NOT by others.

10-30-15: Czarivey
....in Minnesota you need lots of heat in the winter. OTL amps partially solve the heat problems.

True story ....

Our living room is on the main floor & houses the furnace thermostat; the room is hardly used any more as the family room is where the guests go at the other end of the house. Hiding from my wife in this living room - a pair of modded Acoustat Model 3's. So one very cold Ontario winter day, I decided to put my OTL's in there, fire them up with the model 3's and do some listening at - low - moderate levels. It was going great. 2 maybe 3 hours had gone by ?? Not sure.. Then my wife opens the door on me and her first words were ...

"why is the house so cold",

quickly followed by ....

"Hey why is so hot in here",

followed by.....

" Hey..Why the hell are you in your underwear !"
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Ralph, yes I had looked at the patent, and I completely agree with your comments.

Tubegroover, thanks for the suggestion! I'll be sure to check out those discussions. Prior to this thread I had no awareness of this amp, as I mentioned earlier, so I'm sure I will find it to be of particular interest.

Best regards,
-- Al

BTW, David most certainly does call his amp an OTL. As Atmasphere states above, the transformer in the Berning amp operates at RF frequencies, while the output transformer of a conventional amp operates at audio frequencies. That is why Berning refers to his amp as an OTL. Those who say otherwise are obviously invested in saying otherwise.

11-25-15: Psag
... That is why Berning refers to his amp as an OTL. Those who say otherwise are obviously invested in saying otherwise.

Certainly not true in my case, apart perhaps from whatever negligibly small interest I might have in not having my original statement that it is not an OTL contradicted.

Also, Ralph makes a good point that the term "OTL" is normally used just in the context of tube amplifiers, since the vast majority of solid state amps don't have output transformers or autoformers anyway. And since the Berning's output stage utilizes solid state switching devices, it arguably does not even fall within that context.

Regards,
-- Al