OTL amplifiers

I would like to say that I am sure the recount of Ralph Karsten demoing his amps' ruggedness by shorting the outputs with a coin and having NOTHING happen is 100% accurate.

The reason I say this, and I am not proud in doing so, is one a couple of occasions, I have shorted the amp by moving my loudspeakers around, frantically trying to wrest that one extra bit of performance via speaker positioning. The stiff loudspeaker cables were not as compliant, and the amp was shorted.

What happened? Nothing!

Except for maybe in one bad situation, no sound coming out of the speakers for a second or so, until I realized what I just did. As soon as I unshorted the amp, the music immediately began playing again. Same as it ever did.

I didn't even blow a fuse!

The only times I have blown fuses was when I really wasn't yet adept at biasing the amps, and I had one setting way out of wack. Other than the fuse, nothing else was wrong.

How many amps, tube or solid state, can match this kind of performance???

I have owned 2 OTL amps, and still own one of them. The ones I have had have been just as reliable and easy to use as any solid state amplifier I ever had. Absolutely no fuss whatsoever. But the sound is better than any other amp I've had by far. I see no reason to avoid OTL for reliability reasons anymore. That is simply a part of their early history, and has no impact on the current crop of OTL amps. I have the Berning ZOTL-type, and I think it may be the best design of all amps ever. And if you want a SET OTL, then it is the ONLY choice possible, because nobody else can make a SET OTL, except Berning.

I was realy speaking in general terms of OTL designes. In particular the protection and auto-bias circuits are implemented either using tubes or transistors depending on model. Amps that are pure tube-OTL with all implemented protection basically overwent tough reliability issues but "naked" tubes still drop the power twice when impedance drops twice and that's in the nature of all "naked" tubes.
OTLs can realy be used successfully in bi-amp applied for active systems where there is no need for higher power i.e. for freequencies from .8k to 20k and that's where most of our ears hear the best clarity resolution.

why doesn't someone ask Dfrigot where he is and see if he can hear one, feel one, seeing is always believing :)
You Berning guys are famous for that :)
Show offs :)

I agree with TWL since I have owned the Berning ZH-270A and I could not think that I will replace with another amp. I am listening every day to the Berning and it makes me addicted to my music more than ever before. But if you own the Berning and will add to it some more tweaks you will love it.