Haven't heard the ARC with The C1's but I also have the C1 sigs. Started with the original C1's then upgraded to the Sigs. I had the Octave V70SE and have since upgraded to the V110. Even had an in home demo of the V40. With each step up with the Octave you get a little more 'control' in the sound.
I have read on the forums here that with ARC tube rolling isn't all that easy to bias the tubes right. Biasing is super easy with the Octave and have rolled many different tubes (that's 1/2 the fun of a tube amp LOL). I did hear and was very impressed with an ARC tube amp driving Sonus Faber Cremora auditor M's. All I remember with the ARC is it had 8 6550 output tubes and the room got very hot in just over an hour. It was after that demo I heard the Dyn C1's and bought them.
Both ARC and Octave are great sounding.
Best of luck whatever you decide
I have read on the forums here that with ARC tube rolling isn't all that easy to bias the tubes right. Biasing is super easy with the Octave and have rolled many different tubes (that's 1/2 the fun of a tube amp LOL). I did hear and was very impressed with an ARC tube amp driving Sonus Faber Cremora auditor M's. All I remember with the ARC is it had 8 6550 output tubes and the room got very hot in just over an hour. It was after that demo I heard the Dyn C1's and bought them.
Both ARC and Octave are great sounding.
Best of luck whatever you decide