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.