Atma-Sphere M60 or David Berning ZH270?

I've never heard either of these amps with co-incidents, but I am one of the few that found the Berning a little more analytical than the M-60s (2.3) with merlins. But if you have young kids, and the amps will be where they can reach them, then that may be the deciding factor. As you would expect, the Atmas run quite hot. Ouch. Sonically, you won't regret either one.

First of all the disclaimer: I am a dealer for Atma-Sphere. I once owned and do think highly of the Berning amp, though I'm not a dealer for them.

The reason I did not become a dealer for Berning is that I preferred the M-60 in a side-by-side comparison in my system, driving original Quad ESL's (the "57's") and some home-brew dynamic speakers. I have heard the Berning and M-60 driving Merlin VSMs, and once again preferred the M-60. I find it to be more lively and have a richer texture, drawing me more deeply into the music.

That being said, the Berning has a lot going for it. It sounds great, is very lightweight, cool-running, and can be used without a preamp. The variable output impedance control is a wonderful feature that I'd like to see on more amplifiers. Pound for pound, the little Berning is more than likely the best amplifier made.

The Atma-Sphere M-60 does require periodic rebiasing, but that takes about one minute and the only tool required is a screwdriver. You also need to observe the turn-on switch sequence, so it's a bit less user-friendly if non-audiophile family members will be operating it. While the M-60 can accept single-ended inputs, it sounds best with balanced inputs (though in the side-by-side comparison I mention above I used single-ended inputs because at the time I didn't have a balanced preamp). Note that you can also run the Atma-Spheres with less than the full tube complement, reducing the heat output and still sounding excellent (and maybe even better?) with a high-impedance speaker like your Coincidents.

I have the impression that the Berning is comfortable with a wide range of loudspeaker impedances (the variable output impedance helps here), but the Atma-Sphere M-60's don't like speakers with impedances below 8 ohms unless the impedance curve is smooth and the efficiency fairly high.

The Berning is a very fine-sounding amplifier and offers an excellent collection of qualities at a very reasonable price. Sonically it's probably among the top 10% of amps in its general power and price range. Given appropriate loudspeaker matching (such as your Super Eclipses), the Atma-Sphere M-60 is the most musically engaging amp that I have heard in its general power and price range (the 27-watt, 845-tubed deHavilland SET is also excellent, though I don't sell it). At that which they do well - which is lifelike timbres and textures, engaging liveliness, and rich inner harmonic detail - the Atma-Spheres are truly superb.

But remember I'm a dealer, fin on my back, toothy grin and outstretched hand...

Duke

Hi, Spencer,

You opinion really help. It gives me more solid affirmation for my thinking. Regarding the combination of Coincedent + M60, I thought Israel voices his speakers on Atma-Sphere especially M60 Mk2, maybe I remembered wrong...

Thanks again.

Swampwalker & Audiokinesis,

Thanks for the input. It appears personal taste do invole in the decision of choosing hi-end component based on sound even for an amplifier which supposes to just amplify singals.

Audiokinesis, interesting point:

"Note that you can also run the Atma-Spheres with less than the full tube complement, reducing the heat output and still sounding excellent"

Does this mean I can use 4 output tubes per channel and get half of the power? Does it applies other Tube amps as well?

Again thanks for input.

Hello Laoyuap,

Yes you can run the M-60 with only 4 tubes per channel. With most speakers that probably wouldn't work well, but your 14-ohm Coincidents are a special case.

When you reduce the number of output tubes in an Atma-Sphere amp, you not only reduce the power output but you also reduce the damping factor (or increase the output impedance - same thing). This means that the bass will not be as well controlled, with most speakers. But if you have high impedance speakers like yours, the bass will probably still be well enough controlled, and the combination should work very well. And the midrange might be just a wee bit better with fewer output tubes.

I don't know of any other amplifiers where you can safely remove output tubes and still operate the amplifier. I'm sure they exist, but just don't know of any offhand.

Best of luck to you,

Duke