Problems getting the best out of my Berning

Hey Tubegroover, Nice Tubes! I just thought that I would pass along my "glare" info. I don't have a 270, so I was sort of just "extrapolating" the PP Microzotl circuit to the PP zh270 circuit. However, I did get a much better midrange smoothness when I got rid of the JAN Phillips 12AT7. So I thought that might help in this case. Of course, 1950's Brimar Black plates would be even better than my Mullard 6201's.

Jeez, I dunno what the problem is, Peter. I hate to say it, but perhaps your digital source is not a good match with the Berning. As you know, I tried to love the Cary 308. In the end, I thought it to be a good unit......for my bedroom setup. (Cary 308, Creek 5330, Dynaudio 1.1s)

I use an Audio Aero Cap MkI, zh-270 and Proac 2.5s. I rolled the tubes and absoluely LOVE my system. Still use Cardas Golden Ref interconnect (am looking at Silversmith) but replaced my CGR speaker cables with TG Audio HSRs.

I thought the 308 was very "shrilly." Maybe it's a bad match going direct to the Berning.

Peter, my experience with the Berning would tell me that there is a problem somewhere. I have a ZH270 matched with AP Avanti III speakers. Some have commented that the Avanti's can be a bit bass shy, but I get terrific bass, clean, clear and musical, all the way down to the limits of the speakers. Part of that is my room, but alot has to do with the Berning's ability to handle bass extremely well.

I rolled the tubes to cryo'd NOS, but to my ears that primarily affected the soundstage, depth, and detail of the sound (more of the same only better)- the bass was there as well with the stock tubes. And it has never been out of balance relative to the midrange as you are describing.

I previously had an Adcom 5400, modded by Stan Warren, which is a decent sounding SS amp for the money, and the Berning is on a different planet, it is so much better. I have not heard the Classe or the Aleph, but I would be surprised if the Berning did not sound significantly better than either one.

Hang in there. Once you get it fixed, I am sure the sound with the Proacs will be pure magic.

Cheers,
Dave

Peter, I'll chime in too here. I have a 270 with the same tube configurations as Tubegroover, running Merlin Milleniums. I'll second tubegroover's opinion on the change in sound going with the cryo'd NOS tubes from ALlan--significant change for the better. Definitely worth the money. To my ears, changing the 6JN6's made a bigger difference than changing the input tubes.
I have also noticed a major difference in going from one CD player to another--at one point I had both an ELectrocompaniet EMC-1 24/192 and a Wadia 861 to play with, and the sound could not have been more different--not that one was 'better', just different presentation. The Electro. had more bass with more 'slam', for lack of a better word, but the Wadia seemed a bit less 'bright'--not that the ELectro. was bright.
Lack of bass was never a problem with the Berning in my system, even with stock tubes. I have never been able to run the Berning in the 'low' setting, because there is just too much bass in my room. THe normal setting has really tight bass, but maybe a little too sterile in the midrange, so I usually run the Berning in the medium setting--the best compromise for my system.
Hope you get this cleared up. For what it's worth, I also have a pair of Transcendent OTL monoblocks, and they don't match up with the Berning at all (although to be fair, the tubes are getting a little old).

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.