Atma-Sphere M60 or David Berning ZH270?

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.

I too have found the Atmasphere amplifiers to be superb. Certainly one the best amplifies that I have heard. Although the Atmasphere may be more fussy about speaker impedance values, and swings, this can be mitigated with the use of the Zero auto-transformer, a device which effectively optimizes the impedance match between the amplifier and the speaker thus allowing the amplifier to synergetically mate with a speaker and realize all the desireable attributes of the OTL design.

I have run both the MA-1 and MA-2 with, and without, the auto-transformer on my Magnepan 3.6's. Also with the MA-1, I pulled tubes to emulate the M60. With the auto-transformer, the vibrant and delicate soundfield was downright arresting. It just sounded like it was suppose to sound - very immediate, very lucid and very real. Nothing hyper-uppered about the Atmasphere.

Speaking about the M60, there is a picture of the new M60 that Ralph is making on one of the sites covering the CES show. It's nice looking unit. I don't know if it is any different to the venerable M60 but, it's worth checking out.

Ralph's newest Rendition Audio Monitor 60 monoblock amplifier: http://www.renditionaudio.com/monitor60.html...


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