Had a short session with C9 yesterday. Only spent around 35 mins with it so it may not be a good representation. Just my impression.
Used only a HD800S provided by shop. Happened to have a iFi Zen Can sitting on the table as well. So could focus on comparing the 2 amp.
N8 4.4 LO as source to C9 to drive 800S, A18t and Odin.. N8 3.5 tube as source for A18t and Odin for comparison.
C9 at Hi gain and A class for 800S, and Low gain and AB class for IEMs. Just test the tube sound.
1. C9 can drive the 800S, but think there s not much advantage compared to Zen Can. Powerful enough, and can show the soundstage capability of 800S, but not really outshine Zen Can by much. The advantage probably only on the tube sound option. But when u think about the price difference, seems a bit hard to swallow.
2. Then used A18t and Odin on the C9 balanced output low gain with tube. Had a feeling it s pushing the bass too much, to an extent that the timbre and extension is no longer there. Thought it s my hearing problem, but when I used back my N8 on tube (SE only), then can got back the high pitch clarity and extension. Maybe becoz both A18t and Odin are easy to drive, but to me I would prefer to use my N8 (or maybe even N3Pro) to enjoy the sound signature of A18t and Odin.
3. The size of C9 is not small, heard will be similar to the upcoming DX300. I can't imagine to carry a C9 and DAP for outdoor use. A N8 and N3Pro will do a better job for my IEMs. And I don't use HP outdoor at all.
If we talk about home use, then I would rather use a simple Zen Can, and add a WA8 if I want the tube sound. Actually C9 does raise my interest on a proper desktop amp. With its price there are loads of option out there.
Just a 35 mins test drive, so please take my impression with reservation...