Tubes Do It -- Transistors Don't.

Sorry Twl, I wrote my response prior to yours showing up and besides it was more tongue in cheek knowing your preference for high efficiency speakers. Your findings are what I suspect and seem consistent.

Tubegroover, see my last post above for my experiences at lower impedances with the Berning.

Karls-I haven't tried the zh270 into a load that dips low or in your case ruler flat at 3.5 ohms but have read and heard many conflicting comments on its performance at the frequency extremes into such loads that I don't know what to think. How about you Twl? Nah you're definitely the wrong guy to ask :)

I sure am curious myself and anyone in the Central Florida area that has such speakers I will gladly bring over this amp to find out first hand. Everyone I know has medium to high efficiency speakers and the amp sounds great on all of them. The high frequency impedance converter adjusts for impedance dips unlike traditional OTL amps which just run out of current unless there are enough output tubes to provide enough. Transformer coupled amps also do the brute force gig which is why they don't fare well into such loads, especially in the bass and why ss is a better choice for across the board performance.

Regardless, my guess is that the tonal balance especially at the frequency extremes may be affected with certain loads. With my speakers the amp is well balanced and extended across the frequency spectrum. The high frequency performance is also right up there with an absolute crystaline clarity with air and space to match. I really can't hear any problems anywhere but I'm still looking. You know something is on the ball when you start critically listening and find yourself just enjoying in spite of yourself, it happens all the time :)

I concur with Fatparrot on the Atma-Sphere assessment. I have heard the Plinius 102's in Jadem6's system and am impressed with the sound he is getting from these amps.

Karls, If I remember correctly, Atma-Sphere states that their amps consume only 10% more power than a similarly spec'ed Class A SS amp. Also, the Atma-Sphere amps do not have to be retubed very often and use low priced tubes to boot.

Karl, I think that it could do it, with the feedback selector switch in the 2 ohm position. My experience with the low impedance on the Bernings is some of the "life" goes out of the music. I think that this limits the dynamic headroom capability of the amp. I did not notice any problems with reproducing the low frequencies with a 4 ohm impedance load. It was most noticeable to me in the midrange vocals, where some "life" left the sound. 6 ohms was just as "happy" as 8, so anything above 6 ohm nominal should not be noticeable. I found this when I was doing some speaker designing for my MicroZOTL which is a push-pull design much like the ZH270 except no feedback. By using some non-inductive load resistors in a series-parallel network across the speaker terminals, I could determine the sonic behavior of the amp at different loads during play. I could determine where it would "harden up", if you will. Now the ZH270 has some limited feedback switching which provides better behavior under some difficult conditions than my no-feedback design. But my output impedance was 1.8 ohms, which is the same as the 2 ohm setting on the ZH270, so I think it would be similar. So I expect it would sound good, but not as good as a 6 or 8 ohm load.

I've been very curious about the Berning but never tried it. Do you have any experience with driving lower-impedance speakers with it? My speakers are a ruler-flat 3.5 Ohms with near-zero phase throughout the entire audio band, except for a single closed-box peak in the bass, so what do you think? I've talked with one zh270 owner who felt that this would be pushing it a little too much, that the amp probably couldn't handle that kind of load. But if you have any comments, I'd love to hear them.

I appreciate the Atmasphere approach, but I can't bring myself to burn that much juice or to think about the retubing costs!

I would add Atma-sphere amps to this list. OTL amps that really "kick" at lower levels. My former amp (integrated) was an EAR 834. Great amp, about the same power as my new Atma-sphere MK60-2.2's, but what a difference in presentation! The EAR had the definate lush tube bloom, sweet but without the bass control and snap that the Atma-sphere has. The Atma-sphere OTL combines the warmth and liquidity of tubes with the punch and control of transistors, without that solid state "hash". (Please email me if you want more info on Atma-sphere equipment. I have no financial interest in this product line, I just know an affordable gem when I hear it!!!)

To further expand on the Berning bass performance I will say that the Berning zh270 amp has bass performance comparable to the best ss amps I have personally heard. With a stable 8 ohm load this amp will deliver full power down to 2hz and listening is believing. I have never heard any tube amp deliver the clarity, pitch definition and sense of real acoustic space in the low bass like this amp. It is comparable to the best ss in these areas if not offering the ultimate slam of a large ss amp. Another example of the converging of the two technologies.

Dburdic, I agree with you about tube systems. I hear the tube amp. Some of the tube defenders call this continuous space. I call it glueon. I like black space. On the other hand, I have yet to hear, vinyl aside, an ss system sound pleasing. Like Tubegroover, I strive for a balance twixt the two. I use a transparent Pass X 150 for power, a Pass Aleph P for gentle switching; and a well tubed Jolida 100 controls the sound. As has been noted, solid state amp technology has progressed, so much so, that you won't hear any evil second order harmonics. Pass X and XA amps are foremost examples. Then again, the Pass amp can sound horrible if used in a poor sounding system. It is a slave to whatever is fed to it. I think we all understand that.

I feel that a considerable cost upgrade was required to get a SS amp that I could live with. I eventually went with Accuphase. It has the so-called 'Accuphase Golden-Glow' sound, a smoothness and fullness similar to tubes, but with the power to rattle the walls. I currently drive it with an Air Tight tube preamp and I am quite pleased with the combo.

KarlS, you need to try listening to a Berning ZOTL. One reviewer, when he was asked about the ZOTL he reviewed, said that it was the best SS amp he had ever heard. Of course it was a tube amp, but the point he was making was, that it had the beauty of a tube amp with the speed and woofer control of a SS amp. The Bernings are remarkable amps.

I own both solid state and tube pre-amps and amps (Placette and First Sound, Pass and CJ). As with many things in life, I can’t decide which I prefer, so I switch off—a month or two with one, then the other. When I make a switch, I’m usually glad I did and wonder what took me so long.

On balance, however, I tend to prefer solid state. For all of the strengths of tubes—the body, the bloom, the emotional connection, and the other qualities, which many of you have articulated so well--most of the time when I’m listening to tubes I am craving greater clarity. Tube amps, particularly at lower listening volumes, tend to sound too “soft” to me, as if I am listening with a pillow over my head.

I am obsessed with the sound of cymbals. If I put on a jazz z recording, regardless of how great the piano or sax or kick drum may sound, if the cymbals don’t have what I believe is correct bite and aliveness, then I can’t be happy. Solid state seems to deliver these qualities more consistently, whereas tubes (my tube amps, anyway) seem rolled. I wish I would not fixate on this so much, but there you are.

However, I’ve come to feel that listening level is a huge variable in all of this and, further, it is too widely ignored by reviewers and audiophiles alike. A story: I was in a dealer’s many years ago listening to one of the original Hales loudspeakers. I remember thinking it sounded awfully dull, like an old Advent or AR speaker. Later, someone else came in to hear the Hales, put on an opera selection and cranked it way up. I was floored! It sounded so much like the real thing! But I rarely listen that loud. I knew then that the Hales were a very good speaker and also that they were not for me.

I tend to listen at low volume, where detail and clarity serve to help the illusion of music. At higher volumes, these may become less important. Most systems are demonstrated at high volumes. At HE 2002, for example, many, many rooms were louder than I normally listen (and many were just too loud, period). (Most also sounded too bright to me, so I don’t think I generally prefer a bright sound.)

A system that sounds good to me at high volume (even lifelike volume) may not be a good choice for me because it may not deliver the goods at the lower levels I typically prefer. If I’ve got the tube amps in my system and I crank it up, the cymbals sound right and the music sounds real, more real than with solid state. But at lower volume…

I would like to see reviewers be more diligent about addressing performance at different listening levels, particularly for speakers and amplifiers.

-Dan

I have to weigh in on the SS side when it comes to amps, not because they are all better, but because a few of them are. While I've heard very good tube amps and can appreciate their abilities, I've never heard one that could do bass so that it sounded real. The current and damping just can't handle it, and so I always end up "hearing" that it's a tube amp. It sticks in the back of my mind and won't go away, reminding me every time I hear the thump that I'm listening to a tube amp. I suppose my value system would be very different if I only listened to chamber music and vocalists, and I have no doubt I would be sitting here extolling the virtues of tube amps. SS amps, on the other hand, have gotten to the point where a few of them really CAN seem to disappear from the chain. Not many, and not until recently, but they're out there. My Ayre V-5 is the first amp I've ever owned, SS or tube, which allows me to actually say (the majority of the time, anyway) that "I can't tell it's there." And in my mind, there is no bigger compliment that can be paid to any piece of equipment.

This doesn't address the obvious and more difficult question, which is whether tube or SS preamps are better. I think tubes have a lot more going for them in a preamp, and may always have the upper hand over SS in this application.

Hey Kevziek...

I hate to break it to you, but on most recordings the instruments ARE panned into place with a mixer. Sorry. :-)

SS amps might be more accurate in that way (allowing you to "hear" the seperation between tracks). I do agree with you though...I think tube designs (done right) sound more musical and real, though I have heard some that sound so friggin' bizarre...it amazes me that people think the sounds they produce sound anything like real instruments. Still...everything is relevant. Some recordings are made using tube mics and tube preamps and others are made with SS mics and preamps, and both can sound amazing if done right.

Each to their own taste! I use 33H on the mid/tweeter panels of Infinity IRS Beta. These panels voiceds with ARC tube products when the speaker was designed. With a good source, I find the 33H and Bat VK50SE preamp combo right on the money, though I have het to try any of the higher-end tube amps on my system, a friend has a similar setup with a Mac 2000 and it sounds good as well.

There is no doubt that tubes come in various flavors and colors, some of which are quite nice. Some are really awful, I'll leave it to you to discern. Imho, for little money you can get a really *nice* sounding amplifier using tubes, one that gives the impression of "musicality" and "smoothness." So, that is all good.

To get a similar result from solid state, imho (again), you need to go an "extra mile" or so to get certain things right, or else you end up with a sound that personally I do not like at all. Unfortunately, a *great number* of manufacturers seem to either have or like that sound...

What I think is needed can be seen on my site in either the SE Mosfet amp design, or better still in the full out Symphony No.1 design.

Having said that, I admit that I *prefer* the sound of a very high quality, high power triode amp on my ESLs over the arguably more accurate and cleaner Mosfet monster(s). However on other systems, there is no horse race at all. And for bass, tubes are definitely on the short end of the stick.

So, the answer is: use the right devices for the right applications. (often that means bi-tri-quad amp'd set ups)

:- )

My first tube amp was a kit I built in the early 60's, I have had a tube amp in and out of my system since. Currently I have two amplifiers, Cary 805B monoblocks(tube) and a Jeff Rowland Model 10(ss). As wondeful as the Cary sounds, I keep the Rowland amp in most of the time. I find the Rowland the best overall amplifier I have heard in my system. In my experience the best ss amps are as musicial as the best tubes,of course they don't sound the same and they both have strengths and weakness but they are more alike then different.

Lamm 1.1 mono blocks do it all
Beautiful tube bloom and air
Rock solid solid state low end authority
Fleshy mid bass texture
Imaging, soundstaging, you pick the positive characteristic

Twl, might as well give them the article. Eduardo de Lima ?

Why Single Ended Tube Amplifiers

I remain,

Hey you guys! How come I seem to be the only one who gets told that I must like the "euphonic" distortion of tube amps.

I read an extremely interesting article the other day on the web. The premise was, that single-ended triode amps sound as good as they do, because of system synergy with single driver speakers(primarily). It seems this guy did some distortion analysis of SETs, and speakers. The SET generated primarily second order harmonic distortion, which was the bulk of the total harmonic distortion measured, very little other. The speakers measured primarily second order harmonic distortion also, with very little other. These distortion characteristics mainly differed in phase relationship.

His hypothesis was that if, by way of chance, the 2nd order distortion of each item appeared at 180 degree phase angles apart, the distortion would be cancelled out, creating the "straight wire with gain" ideal. If they appeared at 0 phase angle(together), they would add, and distortion would double. Since either case was unlikely, his solution was to determine which side of the 90 degree phase angle the intersection was, and phase the speaker wiring to place the phase intersection of distortion closest to the 180 degree mark that you could. This way if it was at 30 degrees and adding, by reversing phase, you could put it at 210 by reversing phase and achieve a high level of distortion cancellation. If you leave it at a phase angle close to 0, then the distortion adds - bad. Since the majority of this occurs in the 2nd order on both items, once a certain percentage of this 2nd order cancellation occurs, the THD is dramatically lowered for both items as a package.

This is his reasoning for why SETs have the remarkable clarity they do, while measuring in distortion %, the way they do.

His finding was that by switching phase connections on your speakers, you could find out which way sounds better(reduces distortion) on your system. You don't have to use measuring equipment, just your ears. The goal is to have the amp distortion cancel the speaker distortion as much as possible with your equipment.

This is not possible with push-pull or SS amps, as their distortion characteristics are comprised of many orders of harmonic distortion, and are not coincident with the distortion characteristics of speakers.

The effect is somewhat lost on multi-driver speakers because of the phase changes induced between drivers by the crossover network.

So, while I cannot personally attest to the veracity of his findings, it sounds like a very interesting explanation for the apparent dichotomy of SETs measuring poorly and sounding great. The amp is not used to drive a measurement meter. It is used to drive a speaker, and as such may exhibit different behaviors when doing so, than some lab freak with a meter may even realize.

Maybe there is no "euphonic" distortion in SET amps, when you connect them to a speaker and listen to music. What a novel concept. I never really liked the sound of a meter anyway.

I actually like pairing a tube preamp with a solid state amplifier. I find this combination gives me the best of both worlds; without the shortcommings of either format individually. This is especially true in more mid-priced systems.

There are also some hybrid tube/solid state amplifiers out there that solve many of the same issues. Blue Circle just came out with two new hybrid amps. You may also want to consider the Sim Moon W5 and Blue Circle BC26 fully solid state amps.

Tubegroover, you forgot thermionic coolosity in your analysis. I find that to be a very critical factor too. As for the either/or thing I agree with Detlof that the "debate" is irate. Some folks like myself have at least one thermionic unit laying around that uses SS to point the ac in the right direction so it can't be all bad.

Sincerely,
I remain

I always like these threads. Anyway, I'll chime in from the SS camp. As Detlof said, I think both types of amps are getting closer, and there are some great amps out there, from both religions. Though I'm still a SS guy (everyone claims I'll change eventually) I do like all the good qualities of a good tube amp, just as the tube lovers do. I've haven't heard a SS amp yet that even gets close when it comes to vocals.

My problem with tube amps is that whenever I listen to one, I can hear the amp, instead of just hearing the music. A finger hitting a string, a stick hitting a symbol, or a hand hitting the skin of a drum, all sound more real to me when reproduced by a SS device. Though SS amps may not have the harmonic richness and spaciousness of tubes, to me they seem to color the sound less.

I feel that there are system synergies that also must be taken into consideration. I have heard a few great ss systems but I have never owned a great ss amp. The price for admission is probably too high for me but as Zaikesman notes with the ML 33H, they are out there.

It seems generally, in a given price range, tubes are easier to live with long term and less fatiguing. I recently heard a Pass X-350 amp in an unfamiliar system and it was terrible, not the amp but the system. Surely something was wrong. I have heard the Pass Aleph's, the 30 watters sound wonderful. Bottom line there is no clear cut winner and there are enough music lovers that listen through SS that are happy to not discount them.

Where ss in general comes up short is in the "release of the note", the inner harmonic realness and decay that one hears with live instruments. The wholeosity (thanks Gizmo for that term) of the sound. This lends itself a "presence", for lack of a better adjective, that in general escapes SS devices and systems, even expensive ones in my experience. On the other hand another discovery over years of listening is that I have less tolerance for slow ponderous tube gear that euphonizes the sound or adds a richness or syrupy quality that isn't real either. The balancing act is to get the best of both worlds without sacrificing the qualities that each offer.

I am a vinyl and tube man, that stated, I find that SS has improved tremendously over the last two decades, so that basically the old dichotomy no longer holds true. I suggest you listen to a well set up Spectral system through very revealing speakers and you will be very surprised. Or take a listen at the value for money excellent Marsh amps, the Gryphons from Denmark, or for much more money, the offerings of Edge and Halcro, of FM Accoustics.

As far as the bottom end of the musical spectrum is concerned, I am not for tubes, for the simple reason that you can get the same results for far less money through SS. Tubes can handle this as well, since about ten years or so, but those amps cost a packet!

Actually the endless debate about what is better is rather outdated and has become purely ideological. Generally amps of both denominations have edged a bit closer to the real thing and besides, one should not really judge them by themselves, I find, but by the chain they are in and what exactly they are being used for, like high end, low end, midrange etc. Cheers,

Based on what I have heard, I find your generalizations to be very accurate as far as they go. I, however, have also not heard the best new SS amps very much at all. From what I have heard, though, I would add that very good SS can give qualities such as transient cleanliness, tactile bass, image density, and even-handed frequency response that will leave many tube amps in second place in those areas. The best price-no-object SS amps I ever personally listened to were the ML 33H monos. It was only a brief audition, but I was left with the feeling that I had never heard any amps just so completely get out of the way without leaving a trace of an artifact behind. It was like listening to air. But then again, neither have I listened to the tubed amps in this price range. In my own system, I only finally became happy when I switched to tubes, and there I stay for the time being.