ATC SCM150 Amp and Preamp recommendations

@lonemountain 

I actually remember when I first reached out to you during my decision process between active and passive SCM150s. You strongly recommended going with the actives, and I took that advice seriously. I spent time listening to them—really trying to connect—but while they were undeniably impressive in terms of clarity and control, I found myself oddly unengaged. Something about the presentation just didn’t draw me in.

So I went with the passives—and as you’ll recall, you kindly arranged to have them shipped directly to my home. That moment marked the beginning of a very different journey. With the passives, I was finally able to shape the sound in a way that felt personal. Pairing them with an ultra-high-current Class AB amp and a tube preamp brought out the harmonics, tone density, and transient realism I’d been chasing. The system came alive in a way the actives simply didn’t.

I do understand and respect the technical benefits of actives—better phase coherence, reduced component variability, and so on. But in my experience, the real-world gains of external amplification—especially in bass authority, dimensionality, and tonal nuance—have made a bigger musical impact. For someone like me, who listens primarily to large-scale classical and acoustic recordings, that nuance is everything.

You also made a great point about how level differences and source material can color perception. It’s something I try to control for when I’m evaluating gear. But those same small differences don’t invalidate what we feel when we’re genuinely moved by a system. At some point, it’s not about which one measures better—it’s about which one connects.

So while I completely respect the elegance of the active design, for me, the passives were never a compromise. They were the doorway to shaping a system that feels uniquely mine—and that makes music feel more human, more alive. Edward 

@lonemountain thank you for participating.  Perhaps ATC will pickup my suggestion of an outboard active crossover?

I imagine the OP made the best choice for his specific situation.

@ei001h  : I pretty much did the same thing as you: auditioned the active and passive version of ATCs and preferred the final system sound with a Moon North amp driving the passives (same exact front end, which included the insanely phenomenal ATC SCA2 Preamp). Based on your descriptions of what you like, I strongly feel you would love the Simaudio Moon 861; maybe just get the a single stereo amp and if you find you still crave extra drive or something (hard to imagine as the 861 is an absolute beast of an amp) you can always add the 2nd and go mono. You might find, however that while you gain authority/maximum headroom you loose something in the process of monos. Only know by trying though, eh?
@yyzsantabarbara I have a Playback Designs USB-X4 on the way for a home demo. I think this is the one that is around 3K msrp. The other playback streamers that I know of are much more expensive.

@dpac996 I was reading a post by someone who got the $3k streamer from PBD and also owned the more expensive PBD one. The person said they kept the cheaper one and sold the uber streamer.

BTW - Nagra licensees the streamer tech from the PBD USB-X4 and sells it for $5k. They do something similar with their $50k DAC which uses the 3rd-tier PBF FGPA  boards.

@ei001h 

Sounds like your journey ended up in the right place.  Ultimately the thing that makes ATC the MOST different is the low distortion drivers.  This is is something both passive ad active users can appreciate when it helps them hear things they otherwise wouldn't.   

Funny how distortion in drivers appears to our ears: not necessarily as a change in tone or audible distortion, but as masking, the veil obscurring information.  Remove that and a world opens up!

The only negative to low distortion is the recods you loved for the music can sometimes soumnd rather awful.  I remember the first time I heard Genesis "Selling England By the Pound" on a pair of ATCs and I was quite disappointed: NO bass at all, almost like it had been rolled off at 400 Hz!  This was likely caused by the mix monitors or mastering monitors having too much bass in the studio and therefore the engineers thought they had ait rght when they didn't.  This was common until they finally realized that a flat speaker or one with less bass was best to mix on.  Getting your monitors right is important to make sure that your fans get to ehar what they expect. 

Brad