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

Showing 4 responses by rushton

Since this thread has been revived, I will offer that I've recently received back from Atma-Sphere my updated MA-2s bringing them to the most current factory spec. The improvements Ralph has rendered since the MkII.2 series was introduced are simply astonishing!

Since many of the changes in the circuits apply to all of the amps in the Atma-Sphere line, what I'm hearing in my system leads me to believe that any comparisons of earlier production runs of any of the Atma-Sphere amps (i.e., prior to the end of 2004) simply don't reflect the full capability of a current production Atma-Sphere amp. From what I've gleaned in talking with Ralph, more improvements were slipstreamed into production at the end of 2004. So, even if the amp has the current MkII.3 model designation or was updated to MkII.3 status, if the update was done prior to the end of 2004, there were still some significant improvements slipstreamed into production towards the end of 2004.

Those of you who have Atma-Sphere amps and have not yet made the most recent updates, you're in for a real treat if you do it. And for those of you who've listened to Atma-Sphere amps in the past, if you liked some of what you've heard, there's much more to like today. I'll post some further observations in another thread when I have the time to pull my thoughts together on this.

(Note to those who don't like manufacturers continually upgrading their designs: please consider that we are talking about "boutique" designers/crafts people at this level of the high end of the audio art. Ralph and others like him are highly creative individual artisans constantly seeking to improve what they are delivering to the public. For me, I'm pleased and grateful that they engage in this continual creative process.)
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,