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

128x128ozzy

I just posted some more pictures of the DIY speakers and my final external crossover on my systems page.

ozzy

Ozzy, I did not opt for the upgraded caps or power boost. My amps are vanilla MA-1's upgraded to 3.3
As things 'burn in', it just keeps getting better.
Bob

gdnrbob,

Did you find the tube heat to be a problem? My Pass Labs Amp gets very hot to touch.

I won't be touching the tubes but I wonder if I will have to listen in my skivvies with the M-60's 24 tubes.

ozzy

Ozzy,
I agree with Al,  what you've assembled looks impressive and I am sure sounds equally so. Curiosity leads me to ask how the music presentation differs in going from the esteemed Pass to the highly regarded Atma-Sphere mono blocks? Congratulations on a terrific audio system. 
Charles 

charles1dad,

Thank you.

In the end I am not rich and after a fair comparison period, I will sell off one of the amps.

ozzy