Problems getting the best out of my Berning

Hello All,

Thanks for your suggestions! I’ll try to provide answers, and then highlight the remaining questions that arise from consideral all the responses:

1. As for the preamp – I’ve run it with and without a Rogue 66. In both cases, I still get the same undesirable tonal balance.

2. As for digital sources, I don’t think that is the problem, because I use the same sources through the other (pre-Berning) setups without ever having these problems.

3. As for impedance matching with the speakers: I’ve tried this with three different speakers (Triangle Titus, Dynaudio Audience 72 and Proac 2.5’s), and relative to the pre-existing amps on each speaker type, this same issue has arisen.

4. I have tried the three feedback settings. I get the best bass response, and an overall more controlled sound on the normal setting. I like the normal and the middle setting. The low setting is too “loose” for me, I perceive a slight distortion to the sound (maybe due to less driver control).

5. As for the tonal balance, I am pleased enough with the high end. A drummer friend of mine noticed that the cymbals and high-hat seemed a bit removed. We both thought that this is due to the psychoacoustics of the prominent midrange.

6. The amp is located at least 8” away from anything with steel in it. Sometimes on the carpet, other times on a wooden platform on the carpet, other times on a wooden bureau.

7. What about break-in time? How many of you who have purchased the ZH270 new had to break in? I take it few had similar problems as me? Anybody know how much break-in is required?

8. I will test all the tubes. I guess I’ll need a tube tester, or maybe one of the (few) electronics shops in town (Flagstaff) has one. There are many for sale on ebay – any suggestions on how to choose? How much would a decent one cost? Anybody wanna lend me one if I cover shipping (only half kidding!).

9. It sounds like changing tubes isn’t going to be the key for tonal balance, and I should start with cables. Any suggestions for good neutral sounding cables to try? The Proac’s are biwirable, and I would likely go that route (Ian, is that what you are doing?). I don’t have a tremendously unlimited budget. So far, recommended cables include: Cardas IC’s ($$$),TG Audio HSRs, Analysis Plus Oval 9’s, and Luminous Tech Syn Sig. Any other suggestions, with a total cable update cost of maybe $500 (IC’s and speaker cables) would be very much appreciated. Which Cardas to go for? Should I not biwire for now, to save money initially?

10. If I do make a tube change, it sounds like I should change the input tubes first (12AT7's) to see what happens. Or should I change the entire tube compliment at once. Again, I’m trying to be cost conservative. It was already a huge enough stretch to purchase the amp.

Thanks again for everyone’s input and concern. This excellent amp must meet its potential! Please keep sharing your suggestions and ideas.

Peter-
Great summary in your last post. My TG Audio speaker cables use banana jumpers.
I have asked another guy to chime in here, too. He's on the west coast and has a Berning, Proac 2.5s and a Cary 306/200 with vol. control.
I heard what you said about the 308 being OK in OTHER systems. I'm sure that's true. But now - in your current system - something is wack. Out of the box, my Berning was great. I can't imagine cables being the culprit. You know the deal, peter - system synergy is key and, at the risk of being redundant, your cdp may be the culprit.
Who knows, maybe things will mellow in the next few days. When did you install it?

The amp only has about 10 hours on it total. The other CDP I'm using with it is an Arcam FMJ CD23.

Peter, don't spend money chasing cable upgrades until you figure out what is going on. In my experience, no cable change will fix a fundamental system problem, which is what it sounds like you have.

But do give the amp more time to break in. Do you have another amp you can try to see how much of the problem is directly related to having the Berning in the system?

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.