Preamp suggestions for Atma-Sphere Class D Monoblocks

@seanheis1

He already bought Ralph's pre.

@roxy54 hopefully others get a chance to hear their power amps for what they are...before deciding whether or not to change the sound. 

I love my solid state Van Alstine power amp with a passive pre. The distortion profile of the power amp is just right for me.   

Seanheis1

I have used two different passive pres in the past, and always felt that something was missing, usually body and dimension. I understand why you might like them, but like everything else, there are trade-offs.

@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.

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

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. 

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. 

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.

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

@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.

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.