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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
bigboltz
48 posts
 
gdnrbob

The M60s drive my Quatros with no problem.  I rarely get past 12 oclock on the volume and its more than enough.  Vandies have a rep of liking alot of power, but are a fairly easy load. 8ohms pretty much strait across. Plus, with the powered subs and hi-pass, no issues.  I thought about the volume control, but I'm already stretching my budget. What do you think of it?  

And I'm really curious about the phono stage. I'm hoping its great, I sold my Allnic 1201 to make this possible.  Tell me I wont be too disappointed!
bigboltz
48 posts
 
ozzy

I heard from Ralph today ( ok, he emailed back cuz I bug him once a week) and he said he's done the initial testing and expects to have it in the system next week.  Maybe my pre and your amps will end up testing together!    Anyway, I can't say enough about the level of customer service AtmaSphere has given me.
ozzy's avatar
ozzy OP
3,650 posts
 

jond,

Thanks! Believe me I'm savoring...

bigboltz,

Though I don't have the Quatros, I will be using subs and just the signal from 80hz and up will be powered by the M-60's. Do you know the crossover frequency of your subs / Quatros?

And, thanks for your update, mine is still on the work bench waiting for parts.

ozzy

bigboltz
48 posts
 
ozzy

The Quatros require -3db at 100hz.  Ralph is actually building that into one of the outputs for me, so i wont need to use the external crossover(m5hp) that goes between the pre and power amps. Vandersteen has a rather unique way of hi-passing their speakers, whether it be the Quatro and up or model 3 and down used with seperate subs
alexysflores
8 posts
 
You might have to upgrade or replace your current preamp that you are using at the moment since you will be missing the finest tubey sound.  If you have 8 ohms speaker that will work fine with M-60 but if you ask Ralph he recommend to use 8 and16 ohms speakers.  High end 16 ohms speaker such Classic with built-in horn mid range and tweeters are pricey.  The only alternative way to gain 16 ohms is through Zero transformers.

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