I received and installed the 851C in my system on Wednesday afternoon. It's been playing non-stop ever since.
I connected it directly to my Cambridge Audio 840W via balanced ICs, using the 851C’s preamp section to control volume. I was spinning redbook CDs.
Here’s a nano-review:
I was instantly dumbstruck by the two dramatic improvements over my prior equipment (Musical Fidelity M1 DAC -> CODA Technologies 05r Control Buffer preamp--also running fully balanced). The very first impression was the immediate improvement in depth and weight in the LF. The second was greater coherence & resolving power across the entire spectrum. Mind you, the Musical Fidelity / CODA combo was no slouch. In fact, I half expected to return the 851C after experiencing no improvement at all. Overall, I would say the system was similar (don’t know if it is better or worse due to too many years in the interim) from the Theta Digital transport (forget which one) -> Theta DSP Pro Gen Va with 24/192 upsampling upgrade DAC -> CODA Technology 05r Control Buffer preamp -> CODA Technology Model 11 amp. I ran this setup with several speaker systems at different times, but settled on North Creak Music Systems Rhythm Revelators (very similar but superior to the Proac Response 3.5/3.6—I suspect much to the chagrin of that speaker’s designer, George E. Short III—but I digress). I suspect the biggest improvement comes from the DAC in the 851C, but there’s no way to know for sure. The most significant take away for me is that you could buy the 851C + 840W for about the same price as any individual piece in of my prior setup. For now, I’m simply astounded with what I’m hearing.
I don’t have any cans yet, though some are on the way. So, sorry that I can’t at present evaluate the 851C with equipment you’re more likely to be familiar with.
I’ll write more extensively in the near future.