OTL amplifiers

OTL bests with ear-speakers. There I see no compromise whatsoever.

Detlof. You had a Futterman blow on you?

I am reading through the Rosenberg book (from the Sherod thread) on Tube Electronics the last part of which is a long presentation (ad for?) Futterman amps. There was a recent thread here re warranties and everyone was impressed with Bryston's 20 years. That's small change.

The good news is that Rosenberg's book clearly states that the Futterman amps carry a "lifetime warranty!"

The bad news is I'm not sure if they meant your life of Harvey's.

You'll enjoy the book. It has a picture of the pressure cooker Futterman used to prepare the varnish to varnish his power transformers which he then "put on the window sill to cool."

Times have changed.

Sincerely
I remain,

OTL's are usually more expensive, have many tubes - expensive tubes (high current triodes), consume a lot of power, may not perform the same with different speakers, and may not even work with some speakers. Those are, in very general terms without a specific make, the downsides (inconveniences, IMO). The huge advantage is the absence of the output tranformer which means the total harmonic distortion is almost non-existent. That's what gives 'em that incredible sound.

I disagree with tubegroover about a disadvantage being that they run hot. That' a characteristic of Class A operation, not the OTL topology.

>>I disagree with tubegroover about a disadvantage being that they run hot. That' a characteristic of Class A operation, not the OTL topology.

I like your posts GS (cuz I usually lern somethin) but tis a bit form over substance no?

OTLs do, as you say "have many tubes" and they do, as you say, "consume a lot of power" which they dissipate as a lot of heat. That is.... they run hot.

I remain,

Dfrigovt

I would like to mention for your information a few other details. I like you have eclectic tastes in music. Without doubt the most difficult music to reproduce accurately as you might hear it live is orchestral and choral music. The natural layering and individual voices you hear in a great live performance is something that I treasure when I experience it. To build a system that can capture that magic in a home environment is a worthwhile goal. It requires committment, but you can really get close. I wouldn't say that OTL's are for everyone as there are many downside considerations as noted above. All I will add at this point is that you try to listen.

So far as expense goes, Clueless is right about the Transcendent, it costs 2.1K for the T8-LN. It produces 25 watts and is great for a very efficient speaker with a stable impedance of say 6-8 ohms in a small room. I've owned this amp and would recommend it in a heartbeat to anyone that meets those specific requirements. I also believe this amp is an excellent value because it does all the things that seems intrinsic to OTL's if to a lesser degree at a very reasonable price. It is a very serious amplifier.

So far as the Joule goes, I had the opportunity to listen extensively to the VZN 80 stereo amp in my system . At the list price of 8K it appears on the surface to be expensive but when one understands that it is handmade (hardwired, no circuit boards) by the owner Jud Barber, has features including a variac to slowly bring up the voltage of the tubes to the correct operating level, individual biasing of tubes for optimal performance, no guesswork, variable feedback setting along with impeccable fit and finish I think its a bargain. I wouldn't have said this before I experienced this amp . Excuse my excitement but I'm not finished yet!

The amp I currently own is the Berning Zh270 ZOTL. I'm not going to even attempt to get technical because I don't completely understand how it works (Clueless's comment about Berning being bright may be a little understated :) It runs cool 100 watts at idle, can be used without a pre-amp, has 3 feedback settings which effectively can match it with lower impedance speakers, those requiring more current, without changing character or showing if you will a "personality" especially one that may be offensive. It is very tweakable and in my 1.5 years of ownership my excitement hasn't subsided, it just gets better. This amp costs 4.5K retail and I would just love to hear the amp at this price point that competes in the area that this amp excells, top to bottom clarity, no grain, glare, grit, grain or any other gosh darn G word you can think of. It is just amazing. And it also does bass very, very well.

The above 3 I have listened to extensively in my system. The rest I have heard on several occasions in different systems so I can't comment beyond the fact that every system except one (I think it was the speaker's I didn't like) had some serious magic going on. They are definitely worth looking into if you are willing to live with the speakers that would qualify their use in your system. Music is all about connecting to the emotion, these amps are better at it because they just get closer to it. In my experience I would say that their price to performance is excellent contrary to Mark. Cavaet, YMMV and IMO a comparably good transformer coupled tube amp will cost more.