2. amps-preamps
  3. 128359-41

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
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ozzy's avatar
ozzy OP
7,542 posts
 

steakster,

Thanks for your info. The Grand Prix amp stands that I am using have little pads that go between the acrylic 3/4" shelf and the carbon fiber stand. They are available in different "squishy" pads for different weight loads. I did try Stillpoints Ultra SS under my Pass labs amp and I did not like the sound with them with my Grand Prix amp stand.

o_holter,

Thanks for your post. My DIY speakers have a very flat 8 ohm load and a high sensitivity rating. Couple that with the high crossover setting , I think they are easy to drive.

ozzy

gdnrbob
4,460 posts
 
How low in frequency do your DIY speakers go?
B
ozzy's avatar
ozzy OP
7,542 posts
 

gdnrbob,

The rated FR is 37 to 4000hz. But that is probably with a ported design and to me would be very subjective anyway. I would say reasonable / usable low end and a non ported design would be about 50-60hz.

ozzy

gdnrbob
4,460 posts
 
Wow, not bad. I own a pair of Zu Omen Bookshelves. They have a similar range, and I like their simplicity (crossover-less). I find it amazing that such a small enclosure can still reproduce such low frequencies.

Will you be adding subwoofers? Looking at the DEQX and its' capabilities, I would imagine that your DIY speakers and a pair of subs could possibly out perform your Egglestons.
Perhaps you could build those, too?
Bob
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