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Problems getting the best out of my Berning

Hello fellow Agoners,

I beckon for help from experienced users of the Berning ZH270! I just received mine new a week ago, and although it is an incredible amp, it is not meeting my expectations. HELP!

First the good news:

This is the fastest amp I have ever head, and it has virtually no noise floor. I am truly impressed with these aspects. It handles most everything with ease and clarity.

Now my system:

Proac 2.5 loudspeakers
Cary CD308 and Arcam FMJ CD23
Kimber PBJ Interconnnects
Audioquest Type 4 cables

(I've also used Dynaudio Audience 72's and all MIT cables, and Triangle Titus + Audioquest Slate cables and PBJ IC's).

OK - now to the problem:

On all three setups mentioned above, the amp seems strongly biased towards the midrange and upper midrange, resulting in a fatiguing presention. There is a significant decrease in bass (not detail, but the actual movement of air) from the other amps I have used for comparison (Classe CAP 101, Pass Aleph 3, Adcom GFA 5400). While the detail and fastness are truly amazing, the midrange emphasis is getting the worst of me!

I've spoken with David Berning and Frank S (FS Audio.com) and both encourage some tweaking to get rid of this perceived (psycho?) acoustic bias. Frank is going to send me some interconnects to try. David mentioned that others have changed the tubes. He doubts anything is wrong with the amp.

Is this all in my head, or have others had similar problems and needed to make adjustments to get it right? While all my other amps are currently SS, I have trouble believing that this is the "tube sound" (I've heard other tube amps). Other threads mention system tweaking to get rid of a "glare" with the ZH270, changing tubes, sensitivity to cabling. My perception of the sound is pretty strong - currently I like my Aleph 3 a whole lot more with the existing setup.

I'm willing to put some time and money into making this work - because in all other respects, this is an absolutely amazing amp. Perhaps it doesn't suit my ear - but I want the advantages of this amp without the disadvantages I just mentioned. Please - suggestions on what to do from all you experienced Berning fans... so many high commendations cannot be that far off (right?).
peter_s
atmasphere's avatar
atmasphere
11,632 posts
 
-Its an easy mistake to make and it would give you the results you have. Try reversing the phase of *one* speaker cable and leave the other alone. Don't pay any attention to the markings on the amp- its possible that it could have an internal phase problem in one channel. Give it a try.
allanbhaganinfo
121 posts
 
I really don't think it's phase, he's not complaining of imaging, which would be the first obvious thing, he also has issues with his pre-amp, he just needs to get it all together and get use to the clarity, as Gbeard stated, he also was set back by the sound for the first little while, it's that different, an very much so from what he is use to.
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kriskosiba
33 posts
 
Peter, I must say this is an unusual description of the Berning. Out of curiosity, what is the amp sitting on? This amp is EXTREMELY sensitive to any metal. I had an experience like this once with my 270. It turned out that one of the binding posts on the amp was touching the rack and shorting out. (thats right, shorting out with out blowing up!) I ran it this way unknowingly for almost two days. I don't know of any other tube amp that would not have turned into a mini nuclear reactor when shorted out for extended period. Also, make sure the other components are at least a foot away from the amp(again due to its sensitivity to metal). I have tried many different tubes in my amp with incredible results as well. Don't give up on the 270 just yet. When the problem is solved, you won't believe your ears.
peter_s OP
1,318 posts
 
Since the cryo'd NOS output tubes created an audible improvement, I decided to go ahead and do the entire tube compliment replacement. From Brendon at Tube World, I got the input compliment that Tubegroover recommended:

12AT7's Brimar Black Plates NOS and 5965's GE "5 Star"

A QUESTION: Brendan sent me two matched pairs of Brimars. How should I arrange them in the amplifier - vertically (pair per side) or horizontally?

Allan will be sending me a new set of Cryo'd tubes shortly.

Thanks Kriskosiba, I am keeping the amp away from steel things, atleast a foot if not more.
joneill
112 posts
 
Kriskosiba and all,

Do you think Symposium Rollerblock isolation devices would be a no-no under the amp?? My experience with other tube amps usually really likes the enviromental isolation they provide. Would the steel ball contact on the chasis bottom be a problem?

Thanks.
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