2. amps-preamps
  3. 190562-2906

Preamp suggestions for Atma-Sphere Class D Monoblocks

As I impatiently await the arrival of my Atma-Sphere class-d monos, I am writing to solicit opinions from experienced members on this site. Balanced inputs and outputs as well as the ability to connect a subwoofer are important. Headphone amp would be nice but not critical. Ditto for built-in phono. These are some of the tube and solid state units I am considering (not necessarily exhaustive):

  1. Atma-Sphere MP-3 mk3.3
  2. Cary SLP-05 (ultimate edition, if I can find a pristine used pair at a good price)
  3. Modwright LS-100
  4. PrimaLuna EVO 400
  5. Supratek - Champagne or 6SN7 Cabernet - I have no idea what the difference between these two are and the website is not helpful at all
  6. Anthem STR
  7. Benchmark LA-4/HPA-4
  8. Bryston BR-20 (or one of their purely analog variants - BP-19?) - I am hesitant to bundle streaming and dac into a preamp
  9. NAD M66
  10. ?

I will initially use the Bel Canto DAC2.8 as a dac and preamp with an Auralic Aries G1.1 as the streamer. My speakers are Totem Acoustic Forest Signatures, sub is a REL s/510 that I seldom use. I am unsure whether I can use the speaker level connections with the A-S monos (my current Bel Canto Ref510S class d amp has a chassis grounding screw to which I connect the REL’s ground wire).

Philosophically speaking, I have owned a wide range of equipment over the years - everything from "measurements above all" type gear (a full Benchmark stack), a few tube pieces (PrimaLuna, Tavish Design, Rogue), Class A amplification (Pass Labs XA-30.8) and a completely active Genelec 8351b based system. I seem to be slowly but surely gravitating towards subjectively great sounding gear, regardless of how they measure - the Totems are a case in point. However, I don’t want to find that I have moved too far in any one direction. At the end of the day, I value realism and emotional connection more than the ability to deconstruct the music but I don’t want to listen to a sloppy system that homogenizes everything. I’m sure this is all clear as mud! It is however, a reflection of where I am at the end of 28 years of being on this hamster wheel. All thoughts and suggestions welcome. Thanks in advance.

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Ag insider logo xs@2x
srama OP
65 posts
 

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. 

soix
9,574 posts
 

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.

Funny you say that.  I demoed a DAC3.5VB in my system (great DAC BTW), and when I used it as a preamp not expecting much I couldn’t tell the difference between it and my Bryston BP6 preamp and was pretty damn shocked by that.  Still, I bet the MP3 is gonna take you to another level entirely and look forward to your thoughts. 

Ag insider logo xs@2x
srama OP
65 posts
 

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.

atmasphere's avatar
atmasphere
11,841 posts
 

Passive has no sound....so when a person says passive sounds like X....X = the natural sound of the power amp & DAC wink 

@seanheis1 This has not been my experience. Sometimes you can get passives to work great and sometimes you can't. One of the bigger variables are the cables in use. With the higher output impedance passives cause the source to have, there is less control of the cable so its more likely to impart a sound.

The opposite of that is the balanced line system that was developed mostly in the 1950s. This was long before exotic interconnect cables existed yet many of the recordings from this era are spectacular! Obviously the interconnects weren't an issue.

We tried a passive balanced line volume control and found it was not any better than single-ended. Yet when we had a buffer system that drove the balanced lines properly, not only did the system sound better but the differences we were hearing between cables vanished.

To my way of thinking not having to worry about what cable sounds best is a huge boon. That is not available with a passive device.

The other aspect of passive volume controls is the value of the control itself. It will have the least impact on the sound if its a low value, for example 10KOhms, except for the problem of sources not being able to drive such a load properly. So depending on the source, you may have to have a passive that has a much higher value. I find the best place for them is inside an existing amp where the output of the control can be controlled by the designer while insuring that the input is something any source can drive.

 

 

seanheis1
626 posts
 

Great points @atmasphere

I have very short RCA cables & my Mojo 2 source is set to 3 Volts...if I set the Mojo DAC to 1 Volt, the sound softens...so having a source with some balls & a short RCA run could be why I’m not getting the thin lean sound.

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