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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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atmasphere's avatar
atmasphere
11,594 posts
 
The Nirvana is a project to see how far we could push the technology. Its power transformers are spec'd differently, it has regulated DC filaments for the driver section and regulated high voltage for the driver section. The amp section is mounted on a subchassis and overall the chassis work is pretty over the top. Because of all the polishing, its been really hard to shoot photos of it!
geoffkait's avatar
geoffkait
23,365 posts
 
The word Nirvana has been way overused. I used Nirvana ten years for the name of my dual layer mass on spring platform that employed very heavy masses and high carbon springs. There's Nirvana Audio cable manufacturer. Then there was the group, Nirvana.
ozzy's avatar
ozzy OP
7,213 posts
 

As I noted in this thread I am using a pair of the Zero Autoformers with my M-60’s. The M-60’s were made with dual binding posts for bi-wiring.

Since my DIY speakers and external crossovers were also built with bi-wiring in mind, I am going to try a second set of the Zero’s to complete the Biwire set up.

Has anyone tried this? Will a pair of the Zero's on each speaker change the impedance?

ozzy

atmasphere's avatar
atmasphere
11,594 posts
 
It shouldn't as long as both are properly crossed over. The portions of the transformer's operation that are out of band with the crossover will see a fairly high impedance which will be transformed to a high impedance to the amplifier. Worth a try- you can't hurt the amp with an adverse load BTW. But I really doubt that it will yield much in the way of an improvement. OTOH, I don't know of anyone whose tried this, so report back :)
jond's avatar
jond
5,668 posts
 
The Tinkerer strikes again! :-p
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