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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

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ozzy's avatar
ozzy OP
7,557 posts
 

atmasphere,

Thank you for the tips. Yes, I am using Grand Prix amp stands.

I got my Chinese output tubes , but I'm still waiting for the Russian tubes.

ozzy

gdnrbob
4,471 posts
 
Thanks Al/Ozzy.
Since were still encased in snow here in the NE, GardenerBob hasn't been doing much gardening. So, after a sunny Friday afternoon, I have been aquainting myself with the DEQX. I still have to go through the Agon thread, but it really is interesting. (Perhaps next winters' project).
@ozzy , I probably will buy used, too. Has DEQX been okay with non original owners, in terms of support?

Bob
bugredmachine's avatar
bugredmachine
469 posts
 
Geez Ozzy, I moved from the east side to the west side a few years ago and I just caught wind of this thread where you are making changes once again. I'm taking delivery of a pair of older Atma's that Ralph did years ago to try my hand at OTL's as well. I bought them last week and they are being shipped now from the west coast. Not thrilled with the expected heat in the room but excited about the potential for another step up in "magical sound".
ozzy's avatar
ozzy OP
7,557 posts
 

gdnbob,

I can’t really comment about DEQX support. ( I hope I don’t have to find out). In actuality the DEQX is more complicated than the on line info shows. But, many of us are now mastering all the quirks and can help you. I must say the finished calibration does not sound in any way digital or with the negatives I have experienced with previous room correction devices. (The current one that comes to mind is the DSPeaker).  The DEQX is the real thing!

bugredmachine,

Now that I’m getting more time with my Atma-Spheres I am so impressed that I can’t imagine anything sounding better!

The heat in my audio room will increase about 4 degrees, IF I have the amps on all day.(12+ hours). This amount is probably not much more than when I used the Pass Labs the same amount of time.

I must add that Ralph at Atma-Sphere is a A+ dealer and will provide help when needed. Highly recommended!

ozzy


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o_holter
978 posts
 
In my experience, amp / speaker / room matching is the way to go with OTL amps. I can get my MA-1s to sound okay with 8 ohm speakers but I chose speakers that have been developed for OTL (Audiokinesis) and have not looked back. It is only then, that you fully hear what the amps are capable of.
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