1. Home
  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

ozzy
steakster
720 posts
 
Thx for explaining why you went from Eggleston to DIY. Quite a jump-shift, I suspect that these speakers sound great - especially with the M-60’s. The price is right, too. ;-)

Here’s a tweak for tube amps that Ralph alluded to in an earlier post.

I used to live near Rick Becker, who writes for EnjoyTheMusic.com. His mantra is that we can get great sound at a reasonable cost - especially via tweaks. I was very lucky to be invited over when he got new toys to review. Under his Manley Mahi, Rick put the Symposium Rollerblocks - with the ball facing down - on to a Symposium Svelte shelf. This provided a bit more punch to the drums. I did this with both my amp and speakers. Try experimenting if you happen to have any Vibrapods around (or Walker Valid Points). Try putting them (points down) under the amps on your Grand Prix stands.


ozzy's avatar
ozzy OP
3,650 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
2,421 posts
 
How low in frequency do your DIY speakers go?
B
ozzy's avatar
ozzy OP
3,650 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
2,421 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
More to discover