Mejames, I would think that any good speaker to your liking would work well with the zh270. Bear in mind that it is 70 watts per channel, so the selection should include that criteria. As you may know already, I am quite opinionated in my speaker recommendations. For HT however, I am less stringent in my opinions. Generally, I would say pick a speaker that would fit your liking for both categories and use them for your mains/fronts for both audio and HT. Since I don't know your particular taste or budget, it's hard for me to recommend a particular speaker, but a full range dynamic type would fit the bill for both applications. An 8ohm load sounds better than 4 on the Berning OTLs. So I would go with 8ohm. Probably an efficiency level of about 92-95 db would give plenty of room for the dynamics of HT. |
jtinn,
Apparently I ruffled a feather or two when I stated my "opinion" that I preferred the Berning to the Tenor. I do agree that the systems were different. I cannot imagine, however, that manufacturers mate equipment at these shows with speakers and associated equipment that they did not feel brought out the better attributes of their products. That being said, I like most people in this hobby, am not afforded the opportunity to take home any and every product for evaluation on a master reference system. This being the case, I choose to participate in attending shows and frequenting audio shops so I can hear as many products as I can and gather as many "opinions" on equipment as possible. I do this with a clear concious in an effort to make an educated and yes, subjective decision on what products I like and dislike. Because as we all know in this hobby, it all comes down to what you like and nobody else.
Kris |
Thorty40: This was made clear back when they were introduced. While it is a brilliant design, it is not an OTL. It is a transformer based amplifier that is biased by a high speed oscillator to reduce hysteresis effect of the transformer.
An output transformerless amplifier does not have a transformer between the tubes and the speakers. The David Berning amplifier has one after the tubes. Ask to see the schematics published in the patent application. In your own statement, you aver:
"Ok, the RF re-mapping occurs through the use of a tiny RF transformer at a carrier freq. of 250kHz."
The transformer you speaker of, is in between the tubes and the speaker leads. Hence, it is in no way an OTL.
To reiterate, it is a brilliant design and while having the ability to drive impedance challenged speakers, if put head to head with a proper OTL on a stable load, you might be surprised at which one sounds better. Again, I want to make it clear that if I had a limited budget and a tough load to drive, I would give the Berning amps real consideration. |
Hi Jonathan
You are right, by the truest definition of OTL, the Berning is not. The patent application and schematic is on Berning's website for those interested. It may be a moot point, the proof is in the listening. I am not certain how it would compare head to head with an ideal load next to the top tier OTL's with all other things being equal. I will say that next to the Transcendent 25 watt amp, there really is no contest. My wife, who could care less, noticed it immediately before she even knew I changed anything. The Berning doesn't take a back seat in any performance area. Then again it is more powerful and this can certainly come into play in the equation. The big difference is the clarity at all frequencies of the Berning over the Transcendent. There is also a better sense of space and definition. Bass performance is in a word, incredible. Not only control but placement in the recording space, much better than the Transcendent. This isn't really a fair comparison since the Transcendent is less than half the price. But to these ears the Berning beats the hell out of any transformer coupled amp I've heard. The Transcendent does too, within its power limitations. It is just that these designs are faster, more resolving and natural sounding.
There are varying opinions about the Berning on some stats, especially at the frequency extremes. This in comparison with other OTL's. With the benign load of Merlin VSM-M's the performance is stellar.
I'll just go on believing that it doesn't get too much better than this. Ignorance truly can be bliss especially at this level of performance. |
Jtinn, your comments are appreciated but in my opinion are quite closed minded about this amplifer design which eliminates the need for an audio output transformer, hence "OTL". Sure, not OTL in the sense of the some 50 year old school of though about OTL tube amps but an OTL design nonetheless.
Please keep in mind this is a new kind of OTL amp design which requires the old school thought of conventional OTL designs to be tossed out entirely and a new sophisticated one to be layed out on the board from scratch.
Anyone want to compare the old school OTL with the new school OTL directly? Please come on by, I'd put this 270 against any other 70W OTL on the market today.
Chris |
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 |
Bill E., I made the same point in my post preceding yours, but since people obviously do care about whether an amp is an OTL or not, let me propose a theory (I should say that I'm an experimental psychologist by training, so explaining why people do things is what I'm supposed to be good at, although most days I wonder about that!:). High-end audio is a social group, a club if you will, and a fairly exclusive one. Within the club, there are 'levels of exclusiveness', kind of like becoming a 32nd degree Mason, or something like that. OTL amps have a certain 'mystique' about them, like they are the 'holy grail' of tube amplification. Being 'recognized' as an OTL confers this mystique upon the amp, and by extension those who own it. OTL owners are serious audiophiles in search of ultimate accuracy in amplifier sound reproduction; everybody else is just playing around.
Now, before anybody who might read this tells me I'm full of crap, I already know that--my wife and kids tell me that all the time. |
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. |
this is not about words, but about performance. i am another fanatical Tenor owner. so far in my experience, the Tenor easily out-performs ANY other amp in my system (or any system with reasonably OTL friendly speakers).
i would love to hear ANY amp that can out-perform the Tenor in my system and if there is a Berning Owner that lives in the Seattle area or in the Northwest.....come on over and see what happens.....our ears can deciede....and i could give 2 rips whether we call the winner an OTL or not. |
Oneprof hits the nail on the head, in fact most of you have it right, non of you are wrong, in a way :)
In a perfect world with a perfect speaker, the Berning may not sound any better than any other OTL but who lives in that perfect world, well, some die hard OTL owners do, the ones that Oneprof is talking about, the Berning amps are not for those types, they want to see banks of tubes, they want to have heat, they want to have problems now and then, it's part of the mystique, like owning an English sports car, you know, it works great this week and they have pride in having it work great this week and that little bit of excitement wondering if it will work next week.
Now, if you want to have an active audio life, with an amp that can handle most anything, last like nothing else, efficient like nothing else, runs cool, in a light weight package and gives you all the advantages of OTL, yeah, I thought so, there is noting else like a ZH-270, is there???!!!
Allan |
Well now you've done it. You've analogized amps to exotic cars. I've had it! Having owned a 512 Ferrari, if Ferrari's or for that matter English sports cars ever ran as consistantly excellently as my Tenor 75's, they would have won every race they entered. And by the way, you can't imagine how much money I'm saving on heat this winter.
I don't know a single thing about Berning amps. I do know hollow intellectual arguments and I have spent a lifetime sniffing them out!
If it looks like a duck and quacks like a duck and walks like a duck...
Bill E. |
Now this is the way it SHOULD be, folks really passionate about how they hear reproduced music. btw Twl, did I say thanks to you for starting this thread? |
Well, this "type" has had the Tenor's for nearly a year now without a single problem, I looked right at them and don't "banks" of tubes ( AR REF 300 MKII's come to mind ), and the heat thrown from them is actually less than many other amps I've had, tube or ss. My audio life is quite active (can't say that about other aspects of my life :), the Tenors handle anything I've thrown at em, "look" cool, are as efficient as I need, and although not a physical lightweight, a definite sonic heavyweight. I'm proud they're working great this week ( and all prior) and excited because I'm pretty certain I'll be listening next week and not wasting time wondering if they'll be working. Oh yeah, they also have all the advantages of an OTL. But most importantly, to me, they sound better than any other amp I've had in my system, mystique notwithstanding. |
I like all OTL's and many other amps as well. It just seems to me that as soon as something was said about Berning vs. other OTL's, the fur really flew. Very interesting. Seems to be a very sensitive issue. I hope everyone is enjoying their amps, and I think it is very informative that readers hear the different sides of this issue. I doubt that anyone on either side will be swayed by this discussion, but the process gives opportunity for each to re-think, re-evaluate, and better understand their positions. And good heated discussion is great to "hone" your argument. I am enjoying this thread immensely! |
Very good points from all.
However, there are dozens of ZH-270 owners that have had trouble free operation for over 5 years.
With an expected output tube life of 20 years, it's safe to say that one can also expect the same in trouble free years from this unit. |
I don't know whether I should post this or not, but here goes....
I read some comments by David Berning himself once about whether his amp is an OTL. I know, I should have the web address for this, but I can't find it right now. I will look for it. It was either on an old thread (2 years ago?) on Audio Asylum, or on a webpage by Gizmo Rosenberg (not sure of spelling). If I remember right, Berning preferred the term ZH (zero hysterisis) over OTL because of issues like those that have arisen here. I have seen Berning amps referred to as ZOTL's. Again, if I remember right, that phrase was coined by Rosenberg. Now, this was a while ago that I read this, so my memory may be faulty (gets worse every year, sometimes every day I think). When I find the address, I'll post it if anyone's interested. But really, like I said before, call it what you will--the issue is PERFORMANCE. When I get my tax refund, I'm planning on buying a used Joule Electra and having a shootout.
John |
those comments were in Positive Feedback in the letter's section a few years back.....he and Gizmo were going at it good as i recall.....i have the issue....will dig it out later. |
You could try effeciency speakers like Lowther ,AER or Voxativ with 16 ohms impedance,I am using a pair Goodmans 612 fullrange speaker 16 ohms with very good results. |
