Problems getting the best out of my Berning

Hi Peter

Initially I would be tempted to agree with Dan but there shouldn't be an impedance mismatch with the Berning/Pro-ac's. It must be elsewhere in your system or set-up. There is another proac/Berning user (Ian where are you?) that loves this combo. Obviously (at least to me) there is something wrong here beyond what you expected. There should be NO tube glare unless there is an interface problem with wire, certainly not from the amp unless you have a bad tube(s) which is possible, but somehow I doubt it, Berning is too meticulous to send out a new product with such a defect. Upgrading tubes will enhance performance but that is not the answer for tube glare with the zh270, break-in possibly.

An emphasis on the midrange is something more puzzling and I have no answer off the top of my head because I don't hear this in my system and never have nor have I heard it with other speakers and the zh270. I would agree that the bass through the Berning won't offer the slam of other ss amps but it should't be a problem, to the contrary. Bass should balance well with the mids and highs. This amp is all about superb tonal balance along with that clarity. You don't mention high frequency performance at all which with the right speakers and wire should be top shelf. So now all that is left is to troubleshoot.

Have you tried the 3 feedback settings. Do you note any changes between them.

What is the amp sitting on, how close to the digital source. The amp uses ultra high frequency so there could be a possible problem with the location of the amp that may be contributing to what you are hearing.

As Dan asked, are you running directly from your digital source to the amp or do you use a pre.

Certainly the MIT's in general are forgiving cables and shouldn't present a problem at all. The fact that you have tried so many different cable configurations leads me to believe that this isn't the foundation of the problem either but still...it wouldn't hurt to try something else, maybe Cardas. I am using Luminous Tech Syn Sig cables with superb results.

Lastly it could be a break-in of the amp. I wouldn't completely eliminate this. I have heard it first hand and it can never be ruled out. The bottom line is the Berning with the pro-acs should be singing in your system and you shouldn't be hearing any of what you are describing. Please keep us updated. I am confident you will find the problem so hang in there.

Twl

I have never had a glare problem with the Berning. Actually it is only the second tube product I've ever owned that didn't have this problem which was usually fixed with rings and better tubes but never completely eliminated, especially the high frequencies which is damn annoying trying to correct. The Transcendent OTL was the only other tube amp that didn't do the ringing/glare thing. I also had this problem with several pre-amps as well. I suppose it can't be ruled out. I would be more inclined towards a bad tube being the culprit rather than the absolute quality of the tubes being used. The tubes are operated very conservatively in this circuit so while better tubes will yield increased performance a bad tube would present very audible problems. Peter if you have access to a tube tester, check out the tubes to see how they measure. Maybe you have a short in one or more.

If all else fails, I will recommend the following tube compliment I use 12AT7's Brimar Black Plates NOS 1950's, 5965's GE "5 Star" NOS Platinum 1% pair 1970's for the input/drivers and you may want to get in touch with Allan Bhagan @ info@allanbhagan.info for the cryogenically treated 6jn6 outputs. These tubes especially made a dramatic increase in performance, like a component upgrade. I still think you have a problem elsewhere, including the aforementioned bad tube (s).

Hi Phild

The Berning doesn't have a standard tube amp sound to be sure but it could never be mistaken for a ss amp. It has the soul of an SET with resolution of low level harmonic detail across the frequency spectrum. It is as airy and resolving of spacial information as any amp I've ever heard, period. Of course I can imagine it not sounding this way if everything else is not right in a given system.

The reason it sounds different from most other transformer coupled tube amps is simply that it is faster which is the OTL sound that you speak of, they all seem faster and more resolving. There is definitely a problem with Peter's system/amp that will be worked out, of that I am certain.

Peter I'm with Ian, your summary was great and I think the problem is narrowed down. Based on what you said I believe there is a tube problem somewhere, more than likely the inputs. You should be getting more bass than you are. This amp goes down to 2hz, almost dc into an 8 ohm load. The bass performance shouldn't even be an issue. With the pro-acs 8 ohm load you should note a big improvement in the bass with the zh270. Further I am really mystified by this glare you are hearing; poor bass, tube glare from the zh270, its gotta be a tube problem.

Try Brendan at tubeworld.com and just get the tubes recommended above, shouldn't be more than 175.00 or so to upgrade all 6. You'll want to do this down the road anyway, it is a great improvement and may just solve the problem. I really believe you have a tube mortality somewhere or a weak tube causing this anomaly. Try this FIRST and forget the wire for now. In the meantime see if you can locate a tube tester. I also don't believe the problem is with the Cary CD308. And keep up posted on the results.

When you get it right then you'll want to try those cryoed tubes for one of the best audio expenditures you'll ever make.

Peter

I don't think the problem is with the output's, the 6jn6 tubes. Generally, a problem as you are describing is in the input/driver circuit, not the output circuit. I would try the inputs first, the tube complement recommended above.

So far as the cryoed 6jn6 output tubes go, try to get in touch with Allan Bghan at the e-mail link above and see if he even has a set of them on hand. I'm not sure that he does but he is talking about producing another batch, mucho inquiries. These tubes are all individually tested prior to the cryo treatment. So he is using the creme de le creme before the process. They are probably a lot better tubes to start with than Berning uses. Twl's point in his first post is a good one and true. The cryoed tubes are well worth it and you might want to just get both the inputs and outputs. If neither of these upgrades turn out to be the problem you still aren't throwing away your money, believe me. You can be assured that there is a system synergy problem but when you find it, your zh270 will be ready and waiting :)

Dan, maybe I didn't make my point clear enough. If there is a bad tube Berning should and will replace it. If one were to be conservative and not spend the money, the tubes should first be tested with a tube tester as noted above. I really believe the most ill advised thing to do at this point is to replace cables and cd players. Peter has 2 cd players and several sets of cables on hand and he is getting the same results. Process of elimination and common denominator leads to the prime suspect being the amp. Since David Berning's products have a legendary track record of reliability, my guess, based on the symptoms, is that there is a tube problem.

You are absolutely right, he should get acceptable performance from the amp stock. The problem is that he isn't so where does the problem lay? That hasn't been detemined yet. My recommendation is on the premise that there is a tube problem but this is not certain. Is the dealer readily available? How much would it cost to ship back to Berning to have him check it out? I am speaking of a 300.00-350.00 total expenditure for NOS and cryoed treated tubes that will improve the performance of the amp in the long run regardless of what the problem is now. If Peter's resources are limited I would recommend first getting the tubes tested to see if that is where the smoking gun is holing up.

Peter If you can find someone in your area, maybe a dealer that has a tube tester or possibly a local electronic technician you might want to also look at that option. Infant tube mortality is not an uncommon thing. It usually happens within the first few months. Dr. Berning hand builds these amps himself. I doubt there is anything wrong with the amp itself. As a last resort you can ship it back but I would look into getting the tubes tested locally, if possible. Shipping always involves the risk of damage, maybe I'm too sensitive to it because I've had my share of damages, UPS!!

Ken

Not to get too far off topic but as a long time Berning owner I would be interested in your comparison of the single ended zero feedback Siegfried to the PP variable feedback of the zh270. I'm sure Twl and others would be interested as well. Thanks.

Allan your statement changing tubes is for tastes, not to bring up performance is an interesting one. While I would agree that changing the inputs was more of a taste thing, my opinion is that it also improved performance.

So far as the cryoed treated 6jn6 outputs are concerned, there was DEFINITELY an improvement in performance, more resolving, more dynamic and just better across every parameter that I can describe, nothing subtle here. It seems Oneproof feels the same way. I really don't think this is a taste issue at all. And who should know better than you.

Ken I find many of your comments interesting. So far as sibilance is concerned I have often found this to be the result of interaction of components and wire and have experienced my share of it. I have never heard this emphasis through the zh270 or the previous Transcendent OTL amp I used. The system is wired with copper interconnects and Millersound speaker cable which is aluminum with covered with a copper flex wrap. I have been using the Millersound in my set-up since I had the Transcendent and it works extremely well to the point that I have stopped looking for "better" speaker wire after going through numerous ones.

The interconnects (Luminous Technology Synchestra Signature) were a notable improvement over the Harmonic Technology Truthlink. The Berning allowed me to hear that Truthlinks are intrinsically smooth sounding cables but somehow there is a sameness to all music, much of the subtle nuance of the performance is missing in action. As it happened a friend bought a pair of Luminous cables and his system transformed, I don't use the word lightly. There was that organic wholeness and a separation of instrument lines ala live music that you speak of that were revealed when one cable from the pre to the amp was installed. It was the most significant improvement I have heard his system make and this includes even swapping the Berning in. To put this in some perspective, he has tried numerous cables including MIT, Exos, Harmonic Tech Pro-Silways and Truthlinks, Tara labs, etc. each resulting in differences and some improvements in one area at the expense of another. The Luminous was a revelation and trying to analyze what happened took a back seat to listening to the music prior to which I had a difficult time doing with this system because I always was drawn to the artifacts of the reproduction, in a word, fatiguing.

I don't want to get into a cable review because my point is to emphasis not only do cables make a difference as you note above, they can make a DRAMATIC difference in bringing out not only the musicality of a system but the artistry of the performance. After hearing this in his system I did some research on the cable to see if there is a reason why it should make such a difference. Pretty straight forward, 6 nines continuous cast, (the truthlink are also continuous cast) with a special termination that may come into play. He brought the cable to my place the next weekend and while it didn’t transform my system like it did his, it was certainly a big improvement in the areas that I felt the truthlinks to be weak. Nuance or realness conveyed much better, which I attribute to greater resolution of harmonic detail, tighter and better control of bass, and probably the most notable, to me an incandescent, airy natural portrayal of the upper frequencies.

My litmus test of how my system is performing is massed vocal recordings, Ode to Joy Beethoven's Ninth John Elliott Gardner on Archiv is a good example. Nothing is more difficult to reproduce and very seldom do I get goose bumps listening to a choir on a stereo system. It is generally so far off the mark of the real thing. The speed I speak of with OTL’s and the zh270 is the ability of the system to reproduce instruments and vocals without overhang or adding a richness and to keep everything together yet to reveal the air, space, image focus and separation of the performers as we might hear it in a live performance. I would think if an amp is too fast, if this is possible, it would have the same effect as a tt platter going too fast, there would be a chance in the pitch of the instruments and voices. What could be perceived as artificial is if the dynamic shadings of the music aren’t keeping up with the above, this could certainly lend a perception of something being amiss. At this level of performance in an audio system, each element of the chain has to complement the others or whatever area has a shortcoming will draw attention to the whole.

Your insight was most welcome. I am currently going direct from the digital source to the amp. Prior to installing the Luminous cables, I was going from my CAT SL-1 pre to the amp and preferred it somewhat better with the truthlinks. There really wasn’t an earth shattering difference. With the Luminous cables there is a big difference and I much prefer direct. The presence on a great performance is palpable. Performances can swell you with emotion. It is a level I’ve never experienced before and it is consistent with music I love and the effect I get when attending a great live performance. I now realize that the pre-amp has to go and have just ordered a new one recently. I wasn’t particularly happy with the phono stage and the line stage is now just ok. I sure hope this new pre can keep up with what I am currently hearing. If I’m real lucky maybe it will be an improvement. What I’m really looking forward to is the phono stage. The bottom line with the zh270 is that I have finally found an amplifier that can showcase the potential of my system. Of course it doesn’t hurt that my speakers are a nominal 8 ohms with no dips that could alter the tonal balance. I generally prefer the normal setting with great recordings. I listen equally as much through the medium setting going back and forth often trying to decide. I only listen to the low feedback setting on overly dry recordings. As Peter notes, it is a bit too ethereal, not real but still pleasing. It’s nice having the flexibility. I sure would love to hear the Siegfried on Siegfried (Wagner’s)

Peter, check out my 2nd 9/26 post it gives the tube set. I certainly hope matters improve with the amp. I really don't think the inputs will change any of your general perceptions. Since you have had the tubes checked and they are fine my guess is you have either a break-in issue or a serious synergy problem. What you are describing I can't remotely attribute to this amplifier. It is the antithesis of fatiguing or tonally out of balance, especially with an 8 ohm load like the Pro-acs. I am also familiar with the sonic characteristics of the ARC and Pass amps you speak of although not in my system nor in yours ;^).