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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

ozzy
ozzy's avatar
ozzy OP
3,650 posts
 

gdnrbob,

In answer to your question about tube quality. I believe that tubes made before transistors took over were considered to be of the highest quality. Especially those made for the WW2 war effort branded JAN. (Joint Army Navy). These tubes were used in submarines and were made to be quiet. The materials used were purer and made to withstand stress and would last longer. Replacement tubes were still made decades later.

I'm not sure when the US stopped making tubes but Russia and China continued.

Tung-Sol is still making new tubes that are said to be of high quality but still probably not as good as the older ones.

Anyone else have some input on the different brands of tubes quality?

ozzy


atmasphere's avatar
atmasphere
7,068 posts
 
@ozzy ,

The Tung Sol name got bought out a few years ago and is now being used to mark Russian-made 6SN7s. Usually these are the same tubes as the Electro Harmonix but with a brown base. They are nothing like the old-school Tung Sols which were a nice tube.

We've had some very good comments on the Psvane, Sophia and TJ Music tubes; along the lines of 'combining the best of the NOS tubes without the weaknesses' which is a pretty strong statement. You do still have to pick them for low noise and microphonics though, but generally this is not a big deal in the amps. 
knghifi
1,667 posts
 
Where's a good source for Russian and Chinese 6AS7?   
gdnrbob
2,421 posts
 
Thanks ozzy, I didn’t realize that new tubes had to be conditioned. When I got my MA-1, I just installed the tubes and listened (well, I did let thing run in for a while). I didn’t know that they were pre-conditioned- Well, I hope the were.
I will be surprised if you don’t keep the Atma’s. And, should that happen, I hope you will give your reasons.
Bob
ozzy's avatar
ozzy OP
3,650 posts
 

knghifi,

I did a search on EBay. There are quite a lot to pick from.

gdnrbob,

Thanks, I went this far expecting big things from the M-60's. But, I'm still not quite sure what to expect. After all, I will be coming from a SS amp that had all the power I ever needed and which has had many reviews that claim the Pass Labs amps has a tube like sound.

So, soon I will know about the Atma-Sphere.

Thanks Ralph for the additional information.

ozzy

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