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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

128x128ozzy
ozzy's avatar
ozzy OP
7,525 posts
 

charles1dad, sbank, almarg,

Thank you so much for the comments and with the information that you have provided. You guys are the greatest and I really appreciate the time and effort provided in your posts.

Some more info.

My final crossover point between the midwoofer and the tweeter is now 2000hz.@ 12db. This is based on trying to match the advantages of both of these drivers. I went to all Mundorf silver, gold, oil caps and Janzten foil inductors. I also ended up using Mundorf extreme resistors with fixed resistors points and not using the variable L-pad. (I will post new pictures in my systems page tonight.).

And, I will redo my DEQX settings once everything is done and burned in a little. I am getting fairly good with the DEQX and have compiled some easier to follow operating instructions than what is provided from DEQX.

Again, thank you for the help.

ozzy

ozzy's avatar
ozzy OP
7,525 posts
 

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

ozzy

gdnrbob
4,458 posts
 
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
ozzy's avatar
ozzy OP
7,525 posts
 

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

charles1dad's avatar
charles1dad
10,250 posts
 
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 
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