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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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charles1dad's avatar
charles1dad
10,250 posts
 
Hello Ozzy,
Well, that says quite  a lot. Purity is immensely desirable yet hard to achieve, it goes hand in hand with naturalness.  This is the mark of genuinely top tier components IMHO.  Congratulations 😊
Charles 
gdnrbob
4,460 posts
 
So, Ozzy, you managed to do the calibrations without help from DEQX?
I am reading the manual. It is pretty detailed, but seems doable.(I still haven't finished reading it completely).
 My biggest concern is interpreting the graphs. Not so much the deviations of frequency but time and phase lag. Maybe it becomes clearer when using it.
Bob

ozzy's avatar
ozzy OP
7,542 posts
 

charles1dad,

Thanks!. I finally received my 1970's new Russian output tubes. With these tubes and my newer 1950's RCA driver tubes, I think I can finally be ready for the final voyage.

But, Ralph says for tube longevity to put these new tubes on standby for 72 hours before using them. That means no music until Tuesday night! Yikes!

gdnrbob,

Yes, I have done probably a dozen or more calibrations. But I guarantee no matter how many times you read the manual the first time you try it you will be going back and forth through the instructions mumbling words that you won't be proud of.

I still have a problem interpreting the impulse response graph and the corrections settings. But most everything else I could help you with. Al is also very knowledgeable about the DEQX and its settings.

ozzy


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almarg
9,670 posts
 
+1 to Charles’ comment. Great job, Ozzy. Between developing the DIY speakers, becoming proficient with the DEQX, and integrating both of them with subs and two very different amps, you’ve certainly dealt with a multitude of challenges.

And Bob, +1 to all of Ozzy’s comments about DEQX. Regarding the graphs, btw, when you go through my posts in the sections of the DEQX thread I referred to you’ll find links I provided to graphs of the speaker and room measurements I took, and the resulting calibrations. As well as descriptions of the necessary measures I took to minimize the effects of room reflections on the speaker measurements, which as will generally be the case included (among other things) moving the speakers from their normal positions. That can be a challenge if the speakers are large and heavy, of course, and for one reason or another it will probably have to be done more than once.

Best regards,
-- Al

gdnrbob
4,460 posts
 
Thanks ozzy and Al! 
I have been reading and rereading the manual, as well as the thread Al linked to.It is a lot of information, and I am not the most technidally proficient person. So, sorry if I repeat something that has already been answered.

Has anyone used the DEQX on phase aligned speakers like Vandersteens? As a Treo owner, I would be curious to see what a phase aligned speaker would show on a graph. I think I saw a mention on the long  thread Almarg linked to, but I can't find it again.
Bob
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