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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
atmasphere's avatar
atmasphere
11,960 posts
 
We've got a lot of positive comments from customers using audiophile fuses.

The location on the amps that makes the most difference is the one by the power cord. That is also the one that is most likely to be blown, as a power tube failure can blow that fuse. The other fuses only blow if there is a serious service issue with the amp; over the last 30 years I can count those failures on one hand.

Because there are three fuses rather than just one, the sonic effect of the fuse is reduced somewhat but you can still hear it.
ozzy's avatar
ozzy OP
7,542 posts
 

Early on I did have a couple of the power tubes blow that took out the fuses. So I’m reluctant to put a $100 fuse there. But, I have coated the fuses with graphene.

Now that the tubes and other changes have settled down someday I will probably try the SR black fuse.

Ralph, What value is that first fuse? I think it was a 3 amp slow blow, is that correct?

ozzy

dragon_vibe
430 posts
 
I have Ordered the following:

TJ Full Music 6SN7

Black Treasure 6SN7

Natural Sound Series 6SN7


These will be used for my MP-1 Pre-amp and Mp-3

I am still looking for tubes to replace the Atma-Sphere Nirvana Amplifier and the 6SN7 that go with the amp. I have ordered some NOS Sylvinia tubes too.

The TJ Full Music is the same as Sophia. I was told both come of the same production line but are labled for 2 different markets.
dragon_vibe
430 posts
 
Im still looking for more 6SN7 Tubes, but wont buy any untill i have spent enough time with the above.

Someone Asked About Atma-Sphere new Amplifier called the "Nirvana"


Maybe Ralph can chime in and explain what so special about these amps and why do they sell for more than the MA2 but produce less power.

atmasphere's avatar
atmasphere
11,960 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!
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