Berning ZH270 Tweaks

Berning owners! Let's share information about the tweaks that we've tried on the amp and their effect. I am hoping to pick up a few tips while hopefully helping other Berning owners achieve better sounc without to much trial and error. I'll go first.

Tube Rolling:
NOS Telefunken ECC801S 12AT7s - Boy, are they expensive!! But they were worth it; this change resulted in removal of a slight edginess that I heard on some CDs and SACDs. The sound became more natural, relaxed, transparent, and less congested while gaining some resolution and soundstage depth. Whereas fatigue was not a huge issue before, it became a non-issue with these tubes. The result was a very discernable difference with no negative effects whatsoever.

NOS Sylvania 6JN6s - These are my latest changes and I have not really heard too much of a difference in sound yet (only listened for a couple of hours so far). I'll give them more time before a close listening session.

GE "5 star" NOS 12AV7s - Wow, where did the bass come from?! I didn't expect much of a change from rolling these tubes, but they had a HUGE impact on bass; it gain depth, authority and definition. Now the size of the venue is more apparent, and music has more weight. I love it! Very positive and noticeable difference for very little money.

Hal-O Tube damping on all tubes - These had the expected affect of tightening the focus and imaging, but wasn't as big of a change as I had expected. Maybe if I listen at a higher SPL, the effect might be more obvious???

Coupling - Tried a few different models (BDR, Aluminum-based, Aurios, etc.), but only heard a very minor improvement with the Aluminum cones. Without A-B'ing I wouldn't have notice any difference, though.

Power Cable - Tried 4 different power cables (ranging in retail price of $50~$600), and the only cable that made any real difference was Virtual Dynamic Power 3. Very reasonably priced cable, but improved the dynamics and bass authority and definition. A pleasant surprise. I might try VD's higher end models. Has anyone tried them?

Power Conditioning - Only tried the original Shunyata Hydra. This seems to clean up the sound a little bit, but at the same time, turned it sterile (if that makes sense). Although the affect was very subtle, the sound seemed to lose naturalness and became a little bit artificial sounding. More "Hi Fi" and less musical. I didn't really care for it, so it is no longer used.

ERS - Bought a couple of sheets and placed bits and pieces on various locations with little impact on the sound (I think I need some guidance on this).

This is the extent of my tweaks so far. The best tweaks have been Tele 12AT7s, GE 12AV7s, VD Power Cable, Hal-O, and the cones, in that order. Hopefully the Sylvania 6JN6s will get on this list as well. This has been my experience (with my system, in my room, blah blah blah). Now let’s hear your experience.
Hi Henry,

I've tried numerous combination at the 12AT position including Amperex Bugle Boys, Tung Sols, Brimars and Telefunkens. They each are different but like you probably prefer the Teles, more natural and a bit clearer, the Brimars are a bit leaner but also extremely detailed. The GE 5 Stars are the best to date at the AV position. If I were you I would try the cryoed tubes from Allan Bhagan. You mention NOS Sylvanias but are they hand selected and cryoed as well? it makes a difference.

ERS stealth boxes over the small transformers, impedance converters and input wire inside the amp makes a significant difference in lowering the noise floor giving a greater sense of the recording venue. I have also tried the Halo rings on both the Outputs and the inputs. On the outputs a bit of dynamics is robbed and I prefer without. On the inputs a subtle but definite improvement.

The power cords that I have tried include Harmonic Tech, Supra, TG Audio, JPC Power Cord and now the Blue Marble which I prefer. I don't believe in paying too much for cords, its easy to can get a little crazy in this area. BTW, maybe the reason I like the Blue Marble and it works so well with the Berning is that it is cryoed and uses the same wire as in the wire mod.

This is the most significant improvement on the amp to date, big, component upgrade big. This tweek was discovered by Allan after trying numerous combinations. I was expecting that this would be a nice improvement after talking with Allan who was very understated about its significance. I was stunned by what I heard. Initially it is a very readily apparent change in the amp, much greater resolution and ease, better bass and more relaxed yet extended high frequency performance. What was even more remarkable is how the amp improved over a 3-4 week period as the wire settled in. It is a really big deal to me and I can't recommend it highly enough. I've had it for about 6 months now and am still shaking my head.

Other tweeks I have tried include Still Points and the Cloud 10 isolation platform. The Still Points offer a bit better image focus but the Cloud 10 renders better overall bass performance, a larger stage area and overall a bit more involving to me, YMMV both are noteworthy improvements in isolationg the amp as to which one is right, Vinh Vu has some measurements he has done with the use of the Cloud 10 and the results are quite impressive. I highly recommend at least trying the Cloud 10 with the Berning, 30 day trial period. It is a very interesting design and it works.
Tubegroover has covered most of the tweaks I know of, but I don't think he mentioned the caps upgrade which also came about through Allan Bhagan. Since I had the caps upgrade done along with the wire upgrade, I can't really say what it did by itself.
I have a stock ZH class of 02, getting a set of Herbie's Hal-O tube dampers tightened up the focus quite a bit for me. Then I got an in home trial of the Symposium Ultra shelf with a set of Rollerblocks, and this combo was well worth the cost. The noise floor disappeared. If I had to describe it, it was like looking at a lake with a low covering of mist on the water, and with the Symposium gear, the mist was gone to reveal a smooth glassy lake. I tried an active power conditioner, but for me it removed some dynamics. So my amp plugs directly into the wall with an Audience PC.

Has anyone tried the Shunyata Hydra yet? I would be interested to hear any thoughts about the ZH and Hydra?
Hello guys,
I've swapt tubes with GE 5 stars and Brimar, and just waiting the ERS+6JN6 cryo from Allan.
I've put on place of existing rubber feet 4 specials made of high density teflon. These has been better than points, G-Flex and Graffite, as they clean up maintaining all the harmonic contents.
Does anybody has made improvement on the potentiometer? Or to get rid of it totaly?
Cabling is another point of improvement, I'm going to cable it with my preferred type soon.
Does anyone had changed caps with improvements? If yes what type did best?


On each of the larger Hal-O's (35X) for the 6JN6s, I have removed one of the four "rings" that actually touches the tube. This has improved the sound noticeably - brought out the air and easiness and increased the dynamics a little bit. Try it.

Also, I have added Granite base under the Solar Points (ver sharp SS cones), and this helped bring out the ambience and venue of the music quite a bit, and raised the soundstage height by a foot or two. I'd consider this a MAJOR upgrade.

Keep 'em coming!!
Hi Henry,
did you really found improvements with Hal-O's on the power tubes? I've read opposite comments on that and actually experiemented too (but not with ZH270 and with EL34's).
Sorry for the late reply.

At first, I didn't find any improvement with the Hal-O's on the power tubes. In fact, I thought it robbed some dynamics and made the sound "boring". After my local dealer told me to try with one of the tube-touching rings removed on each Hal-O (there are 4 for each 35X), I tried it and now hear an improvement vs. no Hal-O. Hope this helps.
Even though David prefers that the ZH-270 not be run through a power conditioner, I've found a marked inprovement in the noise floor running my Berning through a Sound Appications XE-12S conditioner. I use a Elrod EPS 3 Sig PC into the conditioner from a dedicated cryo'd Hubble and a Silent Source Sig Power cord from the analog side of the conditioner to the 270. Absolute dead quiet.

I currently use Tele 12AT7 on the input side but also have a set of Mullard Amperex Branded 12AT7s that I swap out every once in awhile. Andy at Vintage Tube Services recommended the Mullards for the Berning and it was good advice. The Mullards give a richness that I'm particularly fond of with female voices and instrumentals. The Teles are a very different tube but have much going for them as well.

I pretty much have followed Alan's advice as to mods to the 270, from the cryo'd Sylania Output tubes, to the ERS package, and the silver wire upgrade. Every mod has made noticable improvements for resonable cost.