Atma-Sphere M60 or David Berning ZH270?


Hi, I need some helps to decide which one of these two amplifiers to go with my 14ohm Coincident Super Eclipse (SE).

The Atma-Sphere seems a perfect match for the SE at least in impedance matching and at 14ohm, may get more power than 60 watts. The ZH270 may get less than 70 watts @14ohm. However, I have the following concerns for the M60:

1. 8 6AS7 output tubes per side generates a lot of heat and it does not have cage protection. This is quite a problem if you have young children at home like me. The ZH270 has tubes internal (like a Tube preamplifier) and thus safer for young children.

2. 16 6AS7, though last long time, can be more expensive than ZH270's 4 6JN6 if I try to replace them.

Pro for ZH270 can run without a preamp and is auto-biasing.

On the other hand, ZH270 is more expensive ($4995) than M60 MKII.2 ($4250) (current still have a few left).

As far as the most important factor: sound? I have no idea at all. I have not heard either one anywhere. I have owned ASL Hurricane for over a year and like the sound very much but disappointed for the constant re-biasing and QC problem.

Does any one have Reliability problem with either one?

My listening room is 13Wx8Hx26L and I listen almost only classical music from solo violin, piano, to chamber music to 20 century's big symphony orchestra works (Mahler, Strauss, Stravinsky, etc.).

Thanks for the helps.
laoyuap
I'm with you Rushton in terms of artisans and upgrades in your closing note and thanks for the word on updates. I am certainly not interested in looking for something other than what I own but, was interested in hearing Laoyuap's observations considering he has the same speaker line as I. These amps leave me a very, very happy camper. Turns out my Atma's are in line for an update after the holidays as they were built just before serial #646. Because they are Silver Editions they already posses the Caddock resistors and Teflon coupling caps. Fortunately they do not have the class A/B switch (that I would never take advantage of) or the auto-bias (which I find to be just a luxury item). I look forward to the upgrade and plan on keeping the true OTL magic going on in my living room. Happy listening. Cheers!
R_f_sayles, I agree with you about the class A/B switch which I didn't have added for the same reason: would never use it, didn't see any point in adding the complexity (on which Ralph agrees, I believe). I suspect for a Silver Edition the big difference will come from the new regulator circuit for the driver power supply and the re-building of the output section (how the output tubes are wired) which lowers distortion levels even further plus enhances tube life.

Regards,
Hi, fellas:

I apologize for answering this thread late due to busy and laziness. Here are my impressions of the amplifier and Coincident SE:

I think they are very good synergy at least in my environment. I don’t have much experience with varieties of amplifiers to try, but so far I have been very impressed with the sound of this combination.

The Berning ZH-270 seems to possess strength from both world of solid state and tube amplifier without their weakness. To me, it seems to remove a veil between the sources and your ears. It’s clean and clear as those good solid state amps do yet retains the harmonic richness of a tube amp. It makes musical instruments more life-like and less artificial. The high frequencies are clean and smooth and the lows are ample without exaggeration. Listen to the opening movement of the symphony no 7 by Mahler (Tennsted/LPO/Angel LP). The sound of the tenor horn has body and weight yet rich and smooth and the sound clearly comes from right and rear corner of the orchestra. The mid are rich and smooth too as demonstrated on violin/fortepiano by Luca/Bilson playing the Mozart’s violin sonatas (Nonsuch LP). You can clearly hear the musicians breathing of beginning of a phrase as in Mozart B-flat string quartet (Amadeus/DGG LP) or breathing between movements/CD tracks of a piano sonata (Brendel’s Beethoven sonatas Philip CD). I can listen to ZH270 and Coincident SE for a long time without listening fatigue.

Again, I'm very impressed with these two combination.
Thank you for your observations Laoyuap, I'm glad you are happy with the synergy and the sound. I find my Atma-Sphere and Coincident combo to be very much as you described your setup with the Berning in terms of the musicality. Cheers!
This is a great thread! I'm also looking at the Berning vs. M60 choice for Coincident speakers. The high impedence of the Coincidents looks like a natural for the M60's, so I'm glad to hear some positive experiences there.

Another choice that has just come on my radar screen is Bruce Rosenblit's new OTL design, the Transcendent Sounds BEAST, only available as a kit for about $3700.

I'm a OTL believer, altho I've got a few transformer tube amps around too. Right now, in my upstairs system, I'm using the Transcendent T8 OTL with a pair of North Creek Eska speakers, with an impedence "twister" that keeps them around 7.8 ohms, plus/minus 2. These make very nice music, especially believeable on small-scale chamber music, male vocalists and ensemble groups/folk music.

When my Coincidents arrive, I expect they'll be much more efficient, but I'm still looking to upgrade to a higher-power OTL, and I hear the M60 calling my name. So thanks for all who shared perspectives on this thread! Happy ears!