2. amps-preamps
  3. 184569-137818

Atma-Sphere MP3 or something else?

hey all

some quick background. I'm a headphones guy but use speaker amps/pre power combos for my Abyss TC (and previously Susvara). 

current gear is
Primaluna Evo 400 preamplifier
Nad M23 power amp
speaker cables to speaker/headphone adaptor box (with 0dB and -17dB attenuation switch); i use 0dB for the hard to drive headphones, and -17dB for more sensitive headphones like Utopia etc.

i have the Atma-Sphere MP3 on home demo for a couple of days/weeks. had some initial issues with a faulty 12AU7 tube, but Ralph @ Atma-Sphere was great in helping me trouble shoot the unit. Am still having some background mild hum/electrical noise, very faint and only audible between songs/during quiet music or passages. not a big issue; am guessing either the inherent gain or from the rather old 12AT7 tubes.  if i flick the switch on the speaker/headphones adaptor box to -17dB, then the background hum disappears.

from my own listening, i really like the MP3. i think it outclasses the Primaluna evo 400 especially in the low end and mids. top end is less clear/sparkly than the Primaluna, but overall it makes for a very warm, inviting, lush sound. music and staging, pretty much everything sounds grander and "bigger" with the Atma-Sphere.

i'm looking to get a new tube pre. the Atma-Sphere seems like a rather "old" model. i cant find any recent reviews or forum posts about it. anyone here still using the MP3 or have the newer MP3.3 variant? is the MP3.3 an audible improvement over the older models? is it still a "relevant" component? i was also looking at the Modwright LS36.5 but the local dealer doesnt have a unit on hand, so i cant demo it, and it'll be a blind buy.

 

128x128docroasty
marco1's avatar
marco1
519 posts
 

I purchased a demo MP3.3 last summer.  Line level only.  The unit is dead quite.  If you're getting noise, chances are it's a tube. No experience with Primaluna but I have owned several preamps, both tube and SS, both less and more expensive than the MP3 and imo the MP3 bests them all. Never heard the previous versions of the MP3 but its my understanding several improvements were made.  The real advantage imo with the Atma gear is running it balanced.  

 

 

docroasty's avatar
docroasty OP
81 posts
 

@marco1 

thank you for chiming in! after listening with the MP3, i find it hard to go back to my other preamp. Are you running stock tubes and does your unit have the Damping Package option? i was also recommended the VCap upgrade.

marco1's avatar
marco1
519 posts
 

Vcaps only.  NOS tubes.  RCA 12AU7's from the 60's really made a difference.  Older Russian 6ns7 (can't remember who's) not so much so.

atmasphere's avatar
atmasphere
11,809 posts
 

Your amplifier appears to have gain switches on the rear panel. If they are in the high gain position try a lower setting. That might sort your problem.

Make sure the amp and preamp are plugged into a wall outlet that is served by the same AC circuit. If they are on a different circuit, its possible to exceed what is known as the 'Common Mode Rejection Ratio' which can result in buzz/hum.

 

docroasty's avatar
docroasty OP
81 posts
 

i returned the demo unit to the dealer.
i actually really enjoyed the sound of this preamp, but sadly, i couldnt get rid of the background noise.. this despite switching out multiple tubes, cables, etc. I tried it with my speakers (Ascend Acoustics Sierra 2ex) and there was an audible whine from the ribbon tweeters. also moved the entire setup around the house to try different outlets but no luck.

am now considering the Cary SLP-05; emailed them to inquire, and Billy assures me it'll be silent. 

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