Amp shootout.....Tenor 75wi verses Berning ZH270

in a recent thread there was much discusion of the above 2 amps, whether the Berning was indeed an OTL, and which one might be better.

i have no opinion as to whether the Berning is an OTL. but today a Berning ZH270 owner brought his amp over to compare to my pair of Tenor 75wi's. my system is OTL friendly, with easy to drive speakers, so the Berning's acknowledged advantage in driving difficult loads was neutralized.

these amps have very similar power, the Tenor is 75 watts into 8 ohms, the Berning is 70 watts into 8 ohms. otherwise it is not really a fair comparison....the Tenors are $19900 a pair, the Berning $4500, the Tenors weigh 70 pounds each, the Berning weighs about 10 seems like Goliath verses David. the result is somewhat closer than that.

we played three different discs and each of 3 people listened to their disc in the sweetspot. the Berning owner felt that the Tenor had a more dimentional sound, deeper soundstage but felt the Berning was equal in bass extension and detail retreival. the independent listener felt the Berning was excellent for the money but not in the league of the Tenor in any paramter. my perception was similar to the independent listner; that the Berning, at $4500, is amazing in it's top to bottom excellence, dynamics and musicality.....but....does not do things like the Tenor. the sense of space, detail in the soundstage, texture and microdynamics of the Tenor are at a whole different level.....and they better be for $15000 more.

like the Berning owners, i am a shameless Tenor lover and consider the Tenors better than any other amp i have heard at any price, assuming a reasonably easy load to drive.

the Berning is more like a $8k to $10k amplifier.....and Berning owners should be justifiably proud of their amps.

i did think the Berning had slightly more bass slam than the Tenor, but with much less bass articulation and extension than the Tenor.

we spent the rest of the enjoyable afternoon listening to some great enjoyable time had by all.
I like the part about spending the rest of the afternoon listening to great vinyl.
Wonderful observations, a great job in describing the differences, I wish I had been there :)

Now, if you really want to compare oranges and oranges, I have a pair of prototype Berning mono blocks that would retail for $15,000.00.
let's set something up for this summer :)
Fun, fun, fun :)
Great post, Mikelavigne!! It's great to know that the Berning (an amp which I'm not familiar with) could hold it's own with a "killer" like the Tenor! I wonder if anyone out there has done a shootout between or just A/B'd the Tenors and the Lamm ML-1's. Similar price and power, different design philosophy!
Allan, i accept your challenge....i live in the Seattle area....this should be more of a fair fight....which the above was most definitely not.

let me know what i can do to assist setting this up.

and Albert, i agree the best part was the great vinyl.
This is a interesting shootout. I am curious, was the Berning using stock tubes in the input? I own a Berning and have changed the stock input tubes to N.O.S. The difference is anything but subtle. Many of the shortcomings addressed in this thread were the very things which were improved upon substantially. For any Berning owners who are interested, I replaced the 12AT7's with Brimar Black Plates NOS 1950's, and the 5965's with GE "5 Star" NOS Platinum 1% pair 1970's. 270 owners, this is a very worth while upgrade. For a more detailed description feel free to e-mail me directly.

Allan, the real issue to me is how do i as a music lover get the closest to the music. what products will allow me to remove barriers in the musical reproduction chain and allow me as complete musical enjoyment as possible.

my opinion is that an OTL amp with an appropriate speaker is the method that has the best chance of success. so the fact that the Berning can handle less than ideal loads has no value to me as i have already solved that issue with my speakers. why would i go looking for solutions to problems i don't have. when products (amps/speakers) are ideally matched the results can be amazing.

if you have pliers and i have a 10mm socket and we must loosen a 10mm bolt i have the ideal tool but yours will work ok with more varied situations.....why will i want to loosen some other size bolt with my 10mm socket? it is always best when possible to use the tool ideally suited for the job....for the best possible result.

sorry for the lame analogy.....

now, if the question is "what is the most flexible amplifier?" then our methodology would be different.
dear Mike,

great posting. can you provide what systems and softwares(artists and perforamces) are you using for comparing?
it will provide some info for judements.

Yes, you are so right but not everyone has that luxury to find the perfect speaker with the perfect impedance match, and for some, the perfect speaker is an electrostatic, or some sort of Planer, in which case normal amps have difficulties with, far less an OTL.
This is what this amp was designed to do, to take whatever can be thrown at it, an still give you what you hear with the perfect impedance speaker.

So using your analogy, as long as all your bolts are 10mm, then all you need is one tool but some people rather larger bolts, or some smaller ones and a more versatile tool is needed.

You're all set, you have found your Nirvana but what about the guys that have those Spendors, Quads or speaker like these, they deserve their Nirvana as well :)
I am the lucky Berning owner who got to hear his amp in a killer system - Michael is right, the Tenors are better. The Berning is very very good, but the Tenors have more presence, more three dimensionality, more substance in the sound. The Berning is stock - no changes in tubes. Sources were Linn CD12, Marantz SACD-1, Nordost Valhalla interconects, Placette passive remote vol control, Opus MM speaker cables, ELrod pc's, Hydra conditioner, and Kharma Exquisite 1D Speakers (I think that's right). The Berning has only single ended inputs so we used Linn Silver ic's to connect it from the Placette, the only difference in set up from the Tenors. We listened to Bill Evans, Chet Baker, and a Brazilian music sampler, plus some other ensemble jazz.

My feeling is that the Berning is close enough to the Tenor that the differences would be difficult to discern unless the associated equipment was on par with the quality of the Tenors. (I would certainly like the opportunity to test that theory someday in my own system!) There is no doubt that in Mike's system the Tenors are absolutely magical - I have never heard recorded music reproduced so well. And listening to 45rpm vinyl is the best, bar none.
The system of systems is about to be listed again! Since I don't want to screw it up I will let Mike make all of our jaws drop.

Great post btw, very helpful-and the analogy 10mm will probably work for me because I have little nuts! That's a garage joke-sorry :)

This is what we need to see. Rather than arguing about what to call a piece of equipment, compare them for sound. Great posting. However, you didn't mention whether you played around with the settings on the Berning. In my system, switching the Berning from the normal to the medium to the low setting REALLY changes the sound. Did your listening panel have the same reaction with the Berning in all settings?
Again, we need to see more of this type of shootout.
Wonderful Del, well written indeed.

Tireguy, I am glad to see that your Little nuts are metric :) a sorry try at a garage joke :)

This is what audio is all about, nice people trying things out, with real un-biased conclusions.
Thanks so much guys.

Very interesting thread.I agree with Kris about the NOS tubes, but if the Tenors were stock, then the Berning should be also.If the Tenors had tube upgrades, then the Berning was at a disadvantage with the stock Russian tubes. I know NOS tubes made a great difference in my Berning. What kind of tubes are in the Tenors? I essentially agree with Mike that the Tenors should come out on top, given the price disparity, and maybe the higher price included better tubes. I do think that a better comparison would bave been the Berning Seigfried 300b SET ZOTL. The zh270 is a push/pull amp with feedback and that circuit is not quite up to the Tenors' circlotron. The fact that it even got into the ball park is quite a testament to its quality. Most listeners would prefer a single ended sound to a push/pull. I notice no mention of a transformer induced ring, phase shift, or treble rollof by the reviewers about the Berning. So regardless of the argument about OTL/nonOTL the Berning apparently did not exhibit these typical transformer induced characteristics. Mike, we appreciate this shootout you did, as it gives us the chance to gain info from your experience.

I highly recommend you change the input tubes. If you think the Berning is good now, it will be on a different level with good tubes. You would be amazed at the difference.

You know, I completely forgot about the feedback switch on the Berning when at Mike's - we just ran it at the normal setting. I can say that I much prefer the normal setting to medium or low feedback settings with my ML SL3's - the sound turns soft and muffled to my ears compared to the norm setting. (It drives my SL3's beautifully with no problem at all, by the way.)

Oneprof: This is the first tube amp I have owned, and I do not have a broad experience in tube amp listening. The other two participants in our session did not notice any of the negative characteristics you mentioned. We all commented on how good the Berning sounded - it was really neutral in a system that ruthlessly (I wonder where Ruth is?) reveals any coloration. The independent listener commented that the Berning seems to have a great combination of the organic sound that tubes give plus the versatility of driving difficult loads and low maintenance/hassle usually found only with solid state gear, and was amazingly good for the price.

What I learned most from this interesting (and enjoyable) comparison was that the Berning will provide a neutral organic sound like (but not as good as) the Tenors with the advantages of a much lower price and more flexibility in the choice of speakers. However, if one's goal is to assemble a state of the art system, the Tenors (not the Berning) are at the end of that road - but buying the Tenors should be accompanied by a commitment to buy the best of everything else in the chain, otherwise it is like buying a Ferarri to go check the mail.

Allan - My feelings will be hurt if I am not invited to the Berning prototype shootout!

Very interesting thread - I agree that more like this would be great. However, I'm glad I didn't get to hear the system, lest I be forever dissatisfied with my own.
But ya have to admit with the level of front end components and cables that were there, nearly any amp will sound amazing !

just something to think about !
David, you forgot the feedback switch, oh no, you have to go back now, we need to find out what it's like with lower feedback with this system :)
Understandable in your system, feedback was preferred but with this other system, I think low feedback might have been "IT".
Tenors I think are 0 feedback.
Feedback on the Berning could bring it closer, only one way to find out.
We await your second coming :)

You'll be on top of the list for that shoot out :)


The reason I asked about the feedback setting is that on my system, the normal setting seems to be a little too 'dry' or maybe 'analytical'. I end up running mine in the medium setting most of the time. On the other hand, the most noticeable sonic changes when switching from one setting to another don't really correspond to the changes you all pointed out between the Tenors and the Berning, so it might not make any difference.
By the way, why hasn't anybody mentioned strapping two Bernings to run as monoblocks and comparing that to the Tenor monoblocks? I don't know that much about electronics (I just know what sound I like!), so maybe this wouldn't be appropriate. I know it would give the Bernings a slight edge in power over the Tenors. Does strapping amps not designed as 'true monoblocks' result in an inferior sound compared to true monoblocks?
Again, interesting and informative thread. Unfortunately, it makes me really want to get a pair of Joule or Atmasphere OTL's to compare to the Berning, which I was planning anyhow, but I need to upgrade my cables and interconnects, just got a new CD......and so on.

The feedback switch can be dramatic, the size of the sound stage is greatly altered, as well as bass.

It however may not be enough to change the out come, after all, most ZH-270's are in systems not costing as much as the Tenor alone, the 270 is not in that price league but it's nice to know it can play ball in that league :)

I have to disagree with you. The better your front end and cables are, the better your amps have to be in order to take full advantage of all of the extra info. It truly is the neverending journey. Once you upgrade one thing you eventually have to bring everything up to par.

Thanks Mike and all for the great post and responses. The Berning amp, pound for pound, is getting a bit of a reputation. It' almost laughable when you pick them up...and then you listen.


Please "tease" us with a few details about the prototype Berning monoblock.
e.g. how many watts, type of output tube, etc.
Hi All,

I am a very satisfied Berning ZH270 owner. I have changed my tubes to the same set that Kris has, and yes they have made a very significant difference. That said, I am sure the Tenor's sound is a thing of beauty, and I can only wish for a system like Mike's!

David had told me about this shoot out prior to it taking place, and I was very impressed that anyone could even believe the two amps belonged in the same comparision. I have not heard the Tenor's, but they seem to be universally praised.

I can say without hesitation that my ZH is absolutely wonderful. I have had two great amps in my system (the McCormack DNA .05 Deluxe Rev. A, followed by a VAC Ren. 30/30 Mk II) prior to the Berning, but I am so satisfied with the sound of the ZH that I am now looking elsewhere for improvement. Granted my system is modest by comparision to Mike's, but again it is nice to know that we Berning owners are at least in the same ballpark.

Thanks to David and Mike for the interesting thread!

Cheers, Gary
A frien mine who owns the Tenor amps brought them over to Kwann to compare to my Lamm ML1's. After about hour of warm up, we played three discs on my amp. Then we switche to Tenors and played disc in reverse order.

First disc, I just ben over start to laugh. I couldn't help it, but it no close.

My poor frien spen almost 15 grand for his Tenors and all he could do was look up at me with face red. What happene to bass? Where did go?

Midrange-trebles ok on Tenor. It soun nice but no has resolution and refine of ML1.

The Tenor ver nice polite soun amplifier with something that soun like bass, but no really bass. Call Kwann crazy but for 15 grand I no like kick drum soun like somebody punch pillow. My frien had me sell Tenors for his on Audioweb.
The feedback switch does more than just change the amount of feedback. It also changes the output impedance of the amplifier, which can have dramatic effect on the amp's ability to drive certain loads. In the Normal Feedback mode, it has 1.8ohms output impedance which should give best damping, but in the Low Feedback mode, it has about 8ohms output impedance, which would only be good for higher impedance speakers(16ohms). What kind of speakers were used and what load do they present? The setting used may or may not have been the correct one.
After checking the Kharma website, the Exquisite 1D has a 4ohm to 8ohm load, so the Normal Feedback setting on the Berning ZH270 was the correct setting for them.
Well, I went back and read the manual for the Berning. He says that the low feedback setting raises impedence and reduces speaker damping. To quote from the manual:"Speaker damping relates to the control that the amplifier has over the position of the speaker diaphragm. High damping has the effect of causing the speaker diaphagm to start and stop quickly, and its sonic attributes also show up most dramatically in the bass. High damping is likely to give a tighter, dryer, and more analytical sound and low damping is likely to give a more open and resonant sound."

We left the Berning on normal feedback, which is the low impedence high damping setting. That is probably the source of Mike's comment about the greater bass "slam" of the Berning - it was stopping that big 13" woofer in the Kharma's on a dime. Mike says the Kharma's are a flat 8 ohm load. In the specs, the manual says the output impedence of the amp is 1.8 ohms @ normal, 3.8 ohms @ medium, and 8.7 ohms at low feedback setting. Looks like we should have at least tried the low feedback setting, since that would come closest to matching the Kharma's load, and it would have softened the bass because of the lower damping. Oh well, guess we'll just have to revisit this another day.

By the way, I have never heard the Lamms, but I can say that the combination of the Tenors and the Kharmas and Mike's room treatment produces the best, truest, feel it in your gut bass I have ever experienced outside a live performance (and then only if you are in the real sweet spot in the auditorium). Maybe Mr. Kamm could tell is what other equipment he was using in his comparison.
Sometimes presentation can be altered to taste or preference, this is a very big factor, so it's really hard to say, I bet, had they experimented with the feedback switch, there also would be several different opinions on which position sounded the best.

This is too much fun, let's all get together at mikelagvine place this summer :)
The Mono blocks uses the same tubes as the 270, however the power supply is beefier and some other differences.
These amps were really design and built as direct drives, they were sent to Roger West at sound lab, who to my conclusion was amazed by there design and reliability, I think that is one reason for the 3 month stay at sound lab.

They are capable of 110 watts into 8 ohms but 5500V peak to peak, I'm directly driving a pair of Sound lab M3's with them, all 7lbs each :)
I can barely lift the back plates out of the Sound labs, then I put these little light units in behind, direct to stator and boy oh boy.

I rather not comment on the sound, you'll have a hard time believing it, I have a hard time believing it.

We did some comparisons with the 270 and it was certainly in the same family but the mono blocks had something really special going for it :)

I know most of you know the 270, although light, they are by no means empty, the same and more can be said about these Monos, David Berning must have very small fingers.

The technology in these amps are mind boggling, can't really be had anywhere else.
Maybe Mr. Kamm could tell is what other equipment he was using in his comparison.

Who Mr. Kamm? Mr. Kwann answer you!

My speaker is Fischer & Fischer SL1000. It 88db sensitive an better in every way then Kharma 1d. It use better mid driver (seas excel) better tweeter (esotar) an much faster 210 mm Langhub-Tieftöner bass drivers. In Europe consider much better and cose many more dollar then Kharma 1d which is not great speaker. If you like Kharma chance are you not get hear very many great speaker.
I owned the Lamm Ml-1's and now own the Tenors (75wi) both great amps but for me the Tenors are a step ahead of the Lamms in transparency, musicality and overall refinement.....I simply feel more connected to the music with the Tenors. I have used Kharma 1's and Audio Physic Avanti III's in my listening. I have a Burmester 979/980 front end and used the lamm l-1 linestage, Thor TPA 30 and placette passive.
I now use the placette into the Tenors.
Kevin, if your friend has $15k Tenors, they are the 15 watt versions that you are comparing to your 90 watt Lamm ML1s. depending on the speakers you are using, your result is not too surprising.

the 15 watt versions are designed for the Lamhorns (100db efficient) made by Robert Lamare, one of the Tenor partners. a 15 watt OTL is a very wonderful amp, but has some real world limitations. i would also guess the 15 watt Tenors would shame your ML1s on the Lamhorns. everything is context.

i have heard the ML1s on the Kharma Grande Ceramique in the Lamm room at CES, and although very nice, sorry to say they are not close to the performance of the Tenor75Wi on the Kharma Exquisite 1Ds in my room.

your comments would sound ridiculous to any of the 20 or 25 audiophiles that have listened to the Tenors in my room. the most consistent perception is of the best bass extention and definition they have yet heard...... not wooley, loose, slam for slam's sake rock-concert bass.....but natural, articulate, bass that serves and integrates with the music.....extending flat to 25hz and with usable bass information below 20hz.

i have a friend that is the Musical Director and Conductor of a local regional orchestra. he will be recording an SACD this spring with FIM Recordings. when he was recently in my room he commented that it was the first time he had ever heard recorded bass sound "correct" as we were listening to his own recordings on my system.

we could both be right depending on context; maybe someday i'll have the ML1s or ML2s in my room to compare directly with the Tenors, but until then we'll all have to just try to compare what we have actually heard.
Mzn50, think about this for a moment a good front end usually shows up shortcomings in amplification, meaning typically the better your front end the better the amplifier should be. Otherwise whats the point of having a better front end? Would a person really be able to enjoy a great front end to its fullest with an amp that is not up to par?
Kevin: Mike of course is correct. The Tenor 75 watt amplifiers are $20K, and the 15 watt monos are $15K. What seakers did you compared the amps on?

I have listened to both and while the Lamm ML1's and ML2's are wonderful, the Tenor's go a step further in almost all areas. If I did not have a speaker that was right for an OTL, I would not hesitate in buying the Lamm's.
Alan, just out of curiousity, did you compare the prototype monoblock Bernings to a pair of strapped 270's? Power output would be about the same. Maybe that couldn't be done because of other design considerations. I ask because I am toying with the idea of getting another Berning and strapping them. I seem to remember seeing a comment in a post a while ago to the effect that strapping a pair of 270's resulted in sigificant improvment in the sound over a single 270, (maybe that's a foregone conclusion).
We need an OTL (definitional issues aside) convention!

Mike and Del I thank you both for the opportunity to share your impressions with us all. I can't say I'm surprised by the outcome. I have heard too many wonderful comments about the Tenors to think otherwise. Hope to hear someday, maybe the shootout in Seattle?

I would also recommend to other Berning owners to upgrade their input tubes to the Brimar and GE's, the improvement is not subtle. The music seems to somehow escape from the transducer into the room quite magically. It is a significant improvement that can't be overstated.
Mr Kamm/Kwann-Thank you for your most excellent posts. It's always helpful to have the ludicrous and obtuse juxtaposed to cogency for contrast.
John.The 270's are easily strapped into Mono, some Berning customers do this now, it's however only necessary if you have a speaker that needs more power, there seems to be no degradation running the 270 mono but I would not think it would better a single 270 other than in control of power hungry speakers.

Some who have heard both say that the Monos I have, show some trait of two 270's strapped.

Hopefully somewhere this summer, we can really listen to all these togehter.
How about this guys, since Tenor is in Canada, there is the Montreal show next year, March.
How about we all met in that wonderful city and have a blind test with Bernings, Tenors, Lamms and who ever wants to bring what.
Maybe a type of club an ask the manufacturers to participate.
What do you think?
If you can afford Lamms and Tenors, you certainly can afford to fly to Montreal, it's a great show and a beautiful city.
It's the poor Bernings guys that will have to take the bus :)
To be honest, you guys need to swap out the Linn IC and NOS-tube the Berning, which I think remains fair given the price disparity.

Although the CD12 is wonderful - for CD - Linn is quite biased component-to-component towards dynamics and detail at the expense of rear hall depth and liquidity (a house bias). In my experience, albeit limited, with the Berning, it also tends towards detail and "accuracy" if not fed right upstream. Given that the Karma's ceramic drivers can also load towards detail, the IC issue becomes even more critical, especially when we concede that our own experiences show us that the wrong IC -and particularly one designed by a manufacturer who designes its IC's as part of a system without the need for versatility from sysetm to system - can make all the difference in the world.

With that said, I thought the Berning was a nice amp at $4500, but did not consider it world class.

Nice thread though and thank you for your efforts.
I feel the only true way to do these comparisons, is at a show with the true and the brave manufacturers willing to do a fun comparison, with different cables and all.

It's really not a shoot out or a test, as always taste/preference will have a big factor, it's just a bunch of guys interested in this hobby, having fun.

You Tenor, Lamm, Joule, and others, customers, work on your amp company and see if they want to have some fun in Montreal next year.
Then we will all sit down and have some great Canadian beer and debate the OTL terminology, how better can it get :)
I have had a number of e-mails from people interested in knowing more about the direct drive.
Here is a link to a picture of one of the David Berning Prototype Mono's amp/direct drive.
The Garfield ruler is to remind me of what will happen to me if I stick my hand in there.
As of late last night, I did not heed Garfield's warnings and have a nice black and blue finger tip to prove it.
To Jtinn and Mike: Kwann respectfully correct you assumptions.

My friend own Tenor 75 watt amplifiers he buy form dealer for $15k.

Mike say "...but until then we'll all have to just try to compare what we have actually heard." That just what I comment on. I agree. It not close. We just no agree on which amp win. Either my friend. He sell Tenor.
Is not "World Class" a debatable issue or is it absolute? Absolutes seem to work best in a religious context and I sure sense a lot of that in this hobby. To each his own.

To my way of thinking the Berning is "world class" just by virtue of such a product existing, not by anything absolute. Can anyone answer if they heard any product at its absolute best? Truth be told, it can probably always get better, at least perceptably so.

I recently had a epiphany of sorts involving a friend's very familiar vintage system. A major transformation in musical involvement was realized by changing out ONE set of interconnect cables. This simple change did more than my Berning amp did in the same system without the cable swap. I couldn't believe it so I went over a few days later and heard the same thing.

Of the absolute "among the best" what is the absolute best? Let your ears guide you Luke. For as you travel this path ye shall one day realize that it is a never ending journey and nothing is absolute excepting ye shall keep searching.
Kevin....ok...i'll bite....since until about a month ago i owned the only set of Kharma Exquisite 1Ds in the world and i am wondering just how you have such extensive experience with them to be sure they are "not a great speaker" and that some mystery speaker such as the Fischer & Fischer SL1000 "is better in every way than the Kharma 1D". a statement like that might not be too credible if you have never ever heard a Kharma Exquisite 1D (which is most likely the case).

if you want your comments on the Lamm ML1 or the Tenor75Wi to be considered seriously please confine yourself to judgements on products you have heard.

you also mention that your speakers are 88db efficient, if they also have a 4ohm impedence load or lower they would not be appropriate for the Tenor 75Wi and would cause the performance problems you describe. an OTL amplifier is great when used as intended, but is not as flexible as a conventional designe, such as the Lamm ML1.
Mike please don't bite Kwann!

If you believe you have ony pair of 1d, maybe also believe moon made of green chese? Kwann hear 1d in Holland and 1A refrence in Belgium. If you like 1d, that all that matter!
Kevin, i recieved my 1ds in November 2001, they were the first set made. no other sets of 1Ds were delivered until January or Feburary of 2002. if you heard them in Holland, was that in Charles von Oostrom's room?

i am curious about your speakers.....are there any pictures or descriptions of this speaker on the web? i poked around a little and couldn't find any mention of this speaker or brand.
I've read this thread with great interest. I roamed
around the SET OTL world before I finally chose the
Berning Siegfried 811-10 amp, which is the 12ish W/Ch
version using Svetlana 811-10 output tubes. He also
makes a 300B output version, but from all I'd heard and
read the circuit is really optimized for the 811-10 and
sounds great. Also, 811-10 tubes (and 572-10) are
plentiful and cheap.

I wrote to the editors of Listener magazine a while back
and asked them to do a shootout of the various OTL
amp designs . . . certainly there are differences between
circlotrons vs. ZHOTL vs. other strategies. I also think
that the ZH270's performance in these listening tests
is wonderful, considering what I perceive to be its place
in the world of amps.

In my mind, opinion only, the ZH270 represents a tubed
"workhorse" amp which is a great-sounding bridge for
folks who are used to very-high-quality solid-state
equipment and want to move into tubes. Of Berning's
commercial line (prototypes aside), it is definitely
the beefy brother intended to drive lower-impedance
lower-sensitivity (read: SS-type) speakers well. So
you can get into great-sounding tubes with your
existing Linns or whatever it is that strikes your

Of course, there's a lot of taste-issues (chacun son
gout) in tube amps. There are hard-core tube-ophiles
(like me) who greatly prefer low-powered SETs with
high-efficiency speakers, and I can tell you that as
far as that goes, the Siegfried is one of the best
options on the market, and is also is a "good deal"
($5K-$6K) relative to other high-quality SET/OTL amps.
Speakers are arguably the weakest link in my system;
I've got an "inexpensive" pair of Moth Audio Cicada
horns that the Siegfried drives with aplomb. And with
bass, more than you'd expect from their low-end rating
of 60Hz.

Anyway, I guess I just wanted to say that I think the
discussion is quite interesting, but there are (as folks
have mentioned) a LOT of different ways to use tubes.
Push-pull OTL (like the ZH270) is a relatively uncommon
beast; OTL is more common in the low-powered single-ended
triode realm. So who knows.

Also, regarding NOS tubes. I think you can make a huge
difference with the tubes. Not so much with the outputs
as you can with the inputs, as someone has mentioned
using NOS 12AT7s. The Siegfried has 6 triodes/channel
in the form of 2 6SN7s, 1 6J5G, and the output 811-10.
I've got 1940s VT-231s as the 6SN7s and 1950s Tungsram
6J5Gs, and I think the sound is a world better than it
was with the stock Russian stuff. That said, I think
Svetlana and Sovtek are putting a lot into R&D in their
new tube designs (like 811-10, 6H30Pi, etc.) but don't
do as well with their remakes of old designs like 12AT7.

Sorry to ramble. Great discussion!