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Amps Atma-Sphere M-60 Mono blocks OTL design

I just purchased a used OTL Atma-Sphere M-60 mono blocks that I have sent to Atma-Sphere to be upgraded to the current model 3.3 and I also added the option of a higher quality power supply and V caps.

I have sold my old trusted Eggleston Andra 2’s speakers and have built some monitors using Aurum Cantus ribbons (102db) and Aurum Cantus midwoofers (90db) that are both rated as 8 ohm nominal. I have a DEQX Premate and will be crossing over to (2) JL Audio F-113 subs at 80hz.

Currently I am using a solid state high power stereo amp (Pass Labs) that I used with the Andra 2’s.

The Atma-Sphere M-60 is rated at 60 watts class A and is said to work better with higher impedance loads.

It will probably be a few weeks until I get the M-60 and was hoping someone could provide opinions of what to expect.

I listen to late 60 early 70’s classic rock music mostly. Sometimes loud.

ozzy

ozzy
ozzy's avatar
ozzy OP
3,650 posts
 

atmasphere,

Can you share your comparison? Ralph, I know you are the owner of Atmasphere but I would really like to hear your opinion. And Is there an on line comparison?

I am only asking because I really do love the M-60’s amps. But, the Prima Luna gets more press coverage and is only single ended.

I think it would be very interesting for a head to head comparison sound quality wise. I did hear the Prima Luna at a Dealers showroom a few years back and I was not impressed. At the time I was using Pass Labs amp and the Eggleston Andra 2 speakers and the dealer was using Sonus Faber speakers with the Prima Luna.

My bet would be on the Atmasphere stomping the Prima Luna.

ozzy

atmasphere's avatar
atmasphere
7,068 posts
 
OK: you asked. A lot has to do with the speaker of course, but the feedback we have from customers is that if the two amps are on a speaker that is friendly to both that essentially it is as you surmise.

But we get that a lot and not just with comparison to the Primaluna. That such is so is not surprising on two fronts; the most obvious being that obviously the positive comments are coming from customers that set the amps up right. The other is the overall design features of the amp; M-60 has full power to 2 Hz and can play bass quite well, owing to only one stage of gain and a direct-coupled output. With so little to go wrong its obviously very fast and more transparent without brightness. Triode operation. Fully differential. And so on (no single feature, but the combination of all of them makes for what the amp is). manufacturer caveat: we make the M-60 amplifier.
charles1dad's avatar
charles1dad
6,996 posts
 
Ozzy,
I believe a more compelling and "competitive"  comparison would be the Line Magnetic 805ia.  This is a very highly praised 805 tube SET with 45 watt output.  Of course with these types of comparisons, final choice has much to do with plain old taste. Both of these fine  amplifiers will have their passionate and loyal advocates. 
Charles 
mac48025's avatar
mac48025
613 posts
 
I think an M-60 to the Linear Tube Audio ZOTL 40 comparison would be very interesting. David Bernings OTL design and Atma-spheres OTL. Two very fine amps with similar design concept.....or maybe not so similar? I know they are both OTL but after that they may not be similar at all. I've heard the ZOTL 40 and it took my breath away. Would love to hear the M-60, even if it it out of my price range, as I'm sure it would also. 
ozzy's avatar
ozzy OP
3,650 posts
 

atmasphere,

Thanks. I kind of suspected it. It just seems due to the price point there should be some on line reviews comparing the two products.

charles1dad,

Are you aware of any on line comparison of the 805ia with the M-60’s?

mac4845,

You could always do what I did, find good used units and have them upgraded at Atma-Sphere.

ozzy

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