What is the best OTL out there?

Hi David,
Based on word of mouth and reputation I’m sure that Berning amplifier you cite sounds terrific. Sometimes you reach a point where you’re just content with what you have. That’s where I happen to be at this time. 😊😊
Charles,

Al,Charles,My OTL uses 8 or 16 ohms full range speakers,I can use 4 ohms but it's too bright,I am building  an OTL that I can change the output tubes having 7.5,6.3,5.0 & 4.0 volts filament.My OTL use interstage transformer and only one capacitor in  signal path.

HI,you can never tell the best OTL unless you have knowledge of  OTL tube circuitry. 

I love that Bernings amps get picked apart yet when someone says that they use an autoformer after the output of a OTL the only thing heard is the crickets.

I love that Bernings amps get picked apart yet when someone says that they use an autoformer after the output of a OTL the only thing heard is the crickets.

I don't think anyone picks apart the Berning- its an excellent amplifier, a brilliant design, with excellent reviews and isn't an OTL.
As a separate issue, using an autoformer on an OTL allows you to solve problems- usually one where the speaker desired is simply unsuitable for the amp otherwise. We have a lot of customers here in the Twin Cities that like to use Magnaplanars with our amps, and especially with our smaller amps, the autoformers are a good idea. A good number of people that don't have OTLs also use the autoformers, including people with solid state amps, for no other reason than it sounds better. This is true because all amps have lower distortion when driving higher impedances. 

Whether an amplifier is an OTL or not is an entirely different subject from how it sounds. Personally while we make OTLs, I don't see other OTL manufacturers as the competition so much as just other amplifier manufacturers in general.

Atmasphere's point that "all" amplifier types make less distortion when driving higher impedance speaker loads is an audio pearl that is  unrecognized and under appreciated by many listeners. I understand this dilemma given the dominance of 4 ohm speakers in the current High End audio marketplace. Transistor power amplifiers  made these lower impedance speakers quite viable.
Charles 

@ michaela: I have used original Julius Futterman OTL's successfully with Quad 57's and KLH Nines. I presently have a Harvard Music stereo and a pair of H3AA's. The 6HB5 and 6LF6 TV sweep tubes Julius used as outputs could handle 1.5 amps of current apiece. Making them suitable for this application. However, speaker impedances below 6 ohms still stress these OTL's too much. An autoformer is then recommended.

@charles1dad  excellent post! And that's why I say that the transistor ruined audio, it allowed all these hard to drive speakers to saturate the market place. 

Hi 
analoluvr  admittedly with all things considered I do generally prefer tube  amplification rather than  solid state.   In all candor however I have heard very good sounding solid-state products so I won't throw them all out with the bathwater 😊.   Good  implementation of tubes sounds more natural to me  more often than not. Just a personal observation over the years.  I do acknowledge that solid-state dominates the audio market. 
 Charles 
 

 Yes I have heard some very good solid state as well. However I took atmospheres comments to apply to solid state as well but I could be wrong about that as I don't have much knowledge about solid-state here. I run a pair of atmosphere M60s and I am a big fan though admittedly have not heard any other OTL. I did have some pretty good single ended triode amps and preferred the 0TL to that. 

OTL owners always say's the best what they have without comparing other OTL.

Hello Analogluvr,
I’ve heard the Atma-sphere M 60 and also the MA-1 mono blocks and can appreciate your happiness. I’ve had the Coincident Frankenstein MK II SET for 9 years and remain an ecstatic owner. It’s terrific to find audio products that truly satisfy.
Charles

@realdeal,

OTL owners always say that the brand they own is best even though they haven't heard any other brands (not quoting you verbatim here since your choice of wording was so vague/unfortunate). I would say that your observation is largely correct, just as it would be for the SET crowd, the push/pull pentode contingency, the solid state class A fanboys, etc., etc. 

Bottom line, this approach is endemic to virtually all audio discussions concerning any audio gear genre you wish to become involved with. Get used to it.

However I took atmospheres comments to apply to solid state as well but I could be wrong about that as I don't have much knowledge about solid-state here.

My comments include solid state and class D as well. All amplifiers have lower distortion into higher impedances and this always translates to smoother sound with greater detail. Given that some solid state amps are really expensive, the only explanation I have for the persistence of low impedance speakers is that speaker designers are often not that aware of how the speaker/amplifier interface affects the sound and the performance of the amplifier, and by that I mean **any** amplifier.

Of course, when you put an OTL on higher impedance speakers, that's when the magic happens and on such speakers I've yet to hear any competing technology sound better. But of course I make OTLs- I could be biased just like the power tubes in an amplifier are.

Very best: https://www.morrowaudio.com/collections/linear-tube-audio