Atma-Sphere Class D Mono blocks

Chorus

Well-Known Member
Nov 13, 2017
50
13
115
Phoenix
Anyone here have a pair of these yet? From what I hear these will cure you of any tube need.
$5,400/pair. Get in line.


atma-sphere2.jpg
 
Last edited by a moderator:
  • Like
Reactions: DetroitVinylRob

Tuckers

VIP/Donor
Nov 18, 2020
307
245
280
55
OMG I so want to try this. I have a Purifi based amp and have had a GaN Fet amp in house as well. Love to hear what Atma-Sphere has wrought!
 

aLLeARS

VIP/Donor
Feb 20, 2020
61
226
238
60
OMG I so want to try this. I have a Purifi based amp and have had a GaN Fet amp in house as well. Love to hear what Atma-Sphere has wrought!
I've been using them since last June. They have replaced my M60 Mk3 with Caddock, V-cap, PSU upgrades and selected tubes. I was planning to go back to the M60's for the winter but never bothered to put them back in the system. No need.
They sound like really good tube amps as far as midrange naturalness and are incredibly open and airy sounding in the top. The bass has that incredible class-D control on the woofer. It is a two-stage amplifier with an incredibly minimalist signal path and a linear power supply. They sound more focused than the M60. Like what a better lens brings to optics.
Ralph has definitely made a unique contribution to the new class-D world.
Highly recommended!
 

Gregadd

WBF Founding Member
Apr 20, 2010
10,515
1,774
1,850
Metro DC
A solid state amp that doubles down?
Is this heresy, blasphemy or both?
 
Last edited:

aLLeARS

VIP/Donor
Feb 20, 2020
61
226
238
60

Gregadd

WBF Founding Member
Apr 20, 2010
10,515
1,774
1,850
Metro DC

Solypsa

Well-Known Member
Jun 7, 2017
1,811
1,399
275
Seattle
www.solypsa.com
@aLLeARS what pre are you using with the Atma amps if I may ask?

Pretty bold for a multi decade tube amp manufacturer to make a class d amp that might surpass their own, more costly, tube amps ;)
 

Tuckers

VIP/Donor
Nov 18, 2020
307
245
280
55
Which only lends credence to the probable validity of his new product. Not that Ralph needs it.
Said to be also making an Integrated version soon which has my attention.
That interests me even more! I am spinning the Lejonklou Boazu integrated at the moment.
 

aLLeARS

VIP/Donor
Feb 20, 2020
61
226
238
60
@aLLeARS what pre are you using with the Atma amps if I may ask?
The most transparent one possible. I designed custom remote-controlled attenuators for my system a few years back. They are balanced, use relays and Texas Components resistors and are located right at the input of the mono-block amps.
Signal path is DAC, 15' balanced interconnect, attenuator, 1' balanced interconnect, amp.
When I did the comparison between the M60's and Class D's the only thing that got swapped out were the amps. Same interconnect, speaker wire and power cable. Both amps have balanced inputs with 100k Ohm input Z per phase. To the attenuator both amps look identical.
 
Last edited:
  • Like
Reactions: Solypsa

Chorus

Well-Known Member
Nov 13, 2017
50
13
115
Phoenix
Boazu is an amazing product. Fredrik is over the top dedicated to great sound
and for that I bow to him. What speakers are you using with the reindeer?
 
  • Like
Reactions: Scott Naylor

Tuckers

VIP/Donor
Nov 18, 2020
307
245
280
55
I am using speakers of my own design, open baffle, no crossover, 15 inch full range drivers (25hz to 14khz), and Raven M1 supertweeters with a first order crossover at 16khz. All about 8 ohms and 98db efficient. I have made a custom speaker EQ (to boost the bass on the open baffle) that I implement in Roon and in my media server. Very transparent, fast, wide banded, dynamic, bass does go down to about 25hz in my room. So it really is a full range speaker. Very easy to hear differences between components, cables etc.

I've had the Boazu about three weeks. I love the Boazu's design philosophy. It does have a very pristine and transparent sound, definitely musical. But it also sounds a bit smaller, less dynamic, bass is clear, but doesn't have the power of my purifi. I will need at least another month working with it to get the best out of it before I make any real judgements though. My opinion may change!

I had the Orchard Audio Starkrimson GaN amp in for trial. It did lots of things very well, but I ultimately preferred the Purifi in my system. I felt that the qualities that fell short with it were really a matter of my taste rather than empirical. And I think that a real hi-end audio designer could probably get better performance from GaN, hence my excitement hearing about Ralf's new amp :).

The best amps for them has been the Purifi, the First Watt J2 and the Shindo Sinhonia - 40 watt push pull F2a tube amp (I had a full Shindo rig from turntable to amps for a time - miss that!).
 
Last edited:

Solypsa

Well-Known Member
Jun 7, 2017
1,811
1,399
275
Seattle
www.solypsa.com
@Tuckers may I ask what 15" driver you are using? 25hz to 14k is something special ( open baffle bass no less ).
 

Tuckers

VIP/Donor
Nov 18, 2020
307
245
280
55
They are Audio Nirvana Super 15 FERRITE (link). I've had speakers up to $20K of all kinds (and I showed with some of the mega speakers when I was in the industry), but these got me off the speaker treadmill, and sound to my ears more like real music in real space than almost anything I've every heard. Because the drivers are so big and they have a fair amount of excursion you can actually apply a lot of bass EQ without them breaking up or having (again to my ears) audible IMD. They take forever to break in, and I think the supertweeter is needed as it smooths out the top end and extends it beyond my hearing. Very room filling soundstage wider than deeper, probably not the most precise image placement , but spookily realistic on recordings with lots of presence like Nina Simone etc. Simple really can be better :)
 
  • Like
Reactions: Solypsa

Atmasphere

Industry Expert
May 4, 2010
2,336
1,837
1,760
St. Paul, MN
www.atma-sphere.com

Atmasphere

Industry Expert
May 4, 2010
2,336
1,837
1,760
St. Paul, MN
www.atma-sphere.com
Would you likely be doing an integrated version, do you have any pics, thankyou.

Are you likely to do an integrated version? any pics of the monos, thanks.
1646681766246.png
This was taken by a TAS reviewer at the recent Tampa audio show. The amp is a pair of monoblocks so this is one channel.

We are considering a stereo version. Dunno when that will happen right now.
 

morricab

Well-Known Member
Apr 25, 2014
9,391
4,986
978
Switzerland
Damping factor is likely too high to work well with my horn speakers...even if the mids and highs were truly as good as my SET...bass will go AWOL...
 
  • Like
Reactions: Atmasphere

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing