Preamp suggestions for Atma-Sphere Class D Monoblocks

@atmasphere, I just realized that the MP-3 comes with ONLY balanced inputs. My external phono stage only has single ended outputs - can I use a simple rca to xlr cable or do I have to select the version with optional single ended inputs?

Also, does the preamp support connection of a subwoofer through one of its outputs?

@bcsy

Thanks for your offer to chat! I have already ordered the Atma-Sphere MP-3.

After having experienced just how good Ralph’s class d Mono Blocks are, it was a no-brainer to pair them with a preamplifier of his design .

Thank you all for your responses so far.

@0_holter, thanks for your suggestions - I have come across the Aesthetix in various reviews but have never heard them myself. At a superficial level, their stark modern lines don’t appeal to me - I can be shallow like that ;-)

@Soix, the Spatial Audio Raven was unknown to me and it looks very interesting - thanks for sharing that here. I have reached out to them with a couple of questions using their contact page.

@tms0425, thank you for sharing recommendations as well - I’m sure the MP-1 is spectacular, but likely outside my budget, even used!

I also came across the LTA Microzotl Preamplifier Level 2 in another thread. Any thoughts on that particular piece - in absolute terms and as possible match for the A-S class D?

@soix, thanks, that was the first thread that came up when I searched based on your mentioning the Spatial. It does sound very impressive indeed and I was inspired to reach out to them via their website.

I wish I knew how it compares to the MP-3. There is a lot to be said for system energy and surely @atmasphere Ralph would have designed the Class D so they work brilliantly as a pair.

BTW, does the MP-3 have a remote control? I don’t see it mentioned on the product page and lack of a remote is a non -starter for me, especially while streaming.

So many great suggestions, thank you all! 

As @acman3, @armstrod and others have mentioned, the A-S MP-3 is a recurring theme, which is understandable, given the amp it will be paired with. It is definitely on my short list, as long as remote capability is available. Does anyone have comments on their ability to cast a holographic soundstage, realism and tonality?

Backert Labs gets a lot of love here on AudioGon forums as well. Interestingly, I met Bob Backert many years ago (at that time he lived about 25 minutes from where I am, in PA) when the seller of a Musical Fidelity preamp I bought on AudioGon recommended him to fix a problem with it. He impressed me as highly knowledgeable and as a modest, soft-spoken gentleman. I have no doubt that his products are outstanding. However, all except for the "base" Rhumba 1.4 are outside what I want to spend at the moment. Which, of course, may be all I need.

The LTA microzotl sounds great on paper, but probably not the best match for the A-S monos as it does not have balanced outputs. 

@osiris369, I am a fan of the BluOS platform as well and have owned many of their offerings - M10, C389(?) and was initially considering a comprehensive solution such as the M66 or the Bryston BR-20. I have decided ultimately to keep streaming and dac functions separate (as they change the most often) and focus on purchasing a pure analog preamp which is capable of sprinkling a little "magic" into the system.

@rmdmoore, thanks for the +1 for the Modwright LS100 - it is very appealing, especially at used prices. If I understand correctly, however, it is not a true balanced design so I don't know whether I will be losing something with the A-S monos?

As it stands, the A-S MP-3 and the Spatial Raven are tied at the top. It's great to have multiple options! Thanks again to everyone for your much valued opinions. 

@atmasphere, thank you for clarifying regarding the remote as well as the additional insight into the design.

I understand if you would rather not do so in a public forum, but it would be great to hear your engineer’s perspective on the Spatial Raven and the Backert Labs Rhumba, and how the MP3 differs from these designs (or provide some links if you have already discussed this).

The MP-3 has no problem driving the class D to clipping, if that's what you mean. It supports +4dBm which is far more Voltage than most power amps need.

Thank you, that's all I needed to know!

@atmasphere, thank you so much for your detailed response. I cannot claim to understand all the details, but I think I'm following in broad strokes. One thing I noticed in comparison to the other two amps under discussion is the significantly larger number of tubes in the MP-3 - is this because it is the only truly balanced preamplifier is this set? Does this have any implications on maintenance, require more frequent changes to an entire complement of tubes, etc.?

Just to clarify, I don't intend to  jump into the rabbit hole of constant tube rolling - my limited experience with doing this in the past caused more stress than anything else! I'm only concerned with long-term reliability and cost of ownership. 

@avanti1960, thanks for your comment. I did notice the low gain on the A-S class D (compared to the 27 dB on my Bel Canto Ref501S). I can see how the high gain in the Cary can help offset the low gain in the A-S. I would think, however, that the MP-3 would drive the class Ds effectively given they are both from the same designer?

That said, the SLP-05 is hugely attractive - both aesthetically as well as based on the specs. I just don't want to spend close to $8K at its current sale price for the ultimate version, and I'm not crazy about purchasing tube gear that is several years old.

In practice the 6SN7s of the line stage hold up quite well- we rarely replace them in warranty (which is a year on tubes).

@atmasphere, Thank you, that is good to know.

To reference @avanti1960’s post above, I assume there will be sufficient gain between the MP-3 and the Class D to power my speakers (Totem Acoustic Forest Signatures)? I certainly don't want to end up with restrained dynamics or the sense that the music is somehow being strangled.

@atmasphere

Thank you, so it sounds like I can hook up my existing phono preamp to the Monitor 1 or 2 input on the "basic" line stage version.

Understood, connecting a sub will require a Jensen transformer - a quick search did not reveal any xlr in /rca out versions either at the Jensen website or at resellers, but I will look for it when the time comes. Of course, if you have a known source for this item, please do share!

I currently have a single REL S/10 with speaker level connections; however, I won’t be able to do that with the new Class D monos, since the single connector cable will not reach the two sides of the cabinet the amps will be placed in.

BTW, FedEx informs me that the amps were just delivered! Excited to hook them up as soon as I have a few minutes off from my endless day of meetings :)

@ddgtt, thanks for your suggestion. Going by their reputation alone, I have no doubt about its brilliance - unfortunately, it is more than twice my budget :)

Thanks everyone for your suggestions and engaging discussion. I have decided to go with the Atma-Sphere MP3. I received my A-S class D mono blocks yesterday and I am so smitten by them that it is, in my mind, a no-brainer to pair it with a preamp from the same designer. You can see my gushing impression of the Class D’s here:

https://forum.audiogon.com/discussions/atma-sphere-class-d-amazing?page=15

@acresverde 

High praise indeed! I value your personal experience hearing the MP-3 in your friend’s system. I just placed an order for an MP-3 with the V-CAP and chassis damping upgrades - to say I’m delirious with anticipation is understating it!

@soix, @vthokie83. Thank you, I will try and update my experience here once its all settled in.

@hifinut, thanks for sharing your experience. I am glad I arrived at the right decision eventually!

To quote from @acresverde:

The fact that you will simultaneously establish a relationship with one of the most knowledgeable, caring and responsive bunch of guys in all of audio and will be buying American is just the cherry on top.

As my daughters might say - Word.

@seanheis1

I’m not a fan of passive preamps. And yes, I’ve had the Freya + in my system with a different power amp. I have also had a full Benchmark stack - dac3b, HPA-4 and AHB2. A quick look at my feedback history here and at USAM will reveal the insane number of pieces I have gone through in the last few years. As I wait for the Atma-Sphere MP-3, I am using a Bel Canto Dac2.8 as a preamp and the sound is nothing short of spectacular - without a doubt the best my system has ever sounded. To my mind, the A-S electronics are my destination. I can see changing my digital source  or speakers down the road but not the amps. That’s how strongly I feel about them.

As far as I can tell as a lay person, the advantage of a passive preamp is transparency. With a preamp like the HPA-4 whose performance lies at the limits of measurement devices, this issue is moot.

At any rate, one learns over time that there are no absolutes. Statements like “passives” are better than “actives”, or “Class A” sounds better than “A/AB” are gross simplifications that don’t take into account the complexities of how various pieces in the chain interact with one another, the room and the listener.

After years of searching, I feel I have reached a breakthrough with my current system and I am grateful for that. 

John Stronczer is an absolutely brilliant engineer. Bel Canto just hold back on performance to compete in different market segments. JA stated in Stereophile that the E1x was basically as good as it gets from a measurements perspective. I’ve had other BC DACs in the past and they all have the ability to retrieve detail without being in your face. The other aspect of their Dac/preamps I like is their ability to sound great even at very low volumes.