Atma-Sphere M60 or David Berning ZH270?

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

Laoyuap-
Duke's comment "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." is right on the money. I listen to mostly solo and small combo, non-amplified music (folk, blue-grass, blues, some jazz, lots of singer-songwriter stuff, some older rock), and those qualities are exactly what I value. I don't have any experience with either of those amps with full scale orchestral type stuff, bu the solo violin and chamber should be great with the Atmas. I think the Berning is more neutral, faster. The best way to explain it in terms of your musical tastes (forgive me if I'm way off base, I said I'm no classical fan) is just different readings of the same score, or different character of 2 different, great old violins. As far as the practical aspects go, the Berning is the clear winner. Besides those noted above, the Atmas are monoblocks AND (a very big and) laid out with the inputs and the outputs both in the front of the amp (may have changed on new versions). This is a a pain, since with manual biasing (no big deal by the way), you need visual and manual access to the front of the amp, which is where the input jacks and speaker posts are, but the power cord IEC is on the back. If you can place them behind each speaker, with a long IC and short speaker cables, it might work out pretty well, but then there's the kid-factor.