I’ve had the C658 for a few years and I still have mixed emotions and results from this component, especially in respect to DIRAC.
The positives:
1. DIRAC if you have a difficult room.
2. Dual subwoofer inputs with digital crossover allowing you to ease the load on an amp.
3. BluOS UI is rock solid which also allows you to utilize Tidal and Spotify Connect, in addition to Roon.
4. All-in-one (pre, DAC, streamer) = small footprint and less money on interconnects.
5. Volume knob is actually really nice - provides that resistance and weight when turning up or down the volume.
6. Remote included and having a screen that shows volume level, track and album name, and when MQA is being used.
Negatives:
1. DIRAC with mixed results utilizing both the provided mic and a UMIK1. Spent hours and hours researching the best methods to capture good measurements - and still, lots of variability with results with the full version of DIRAC.
2. All-in-one nature - I had a MHDT DAC with a Node 2i, and at times contemplate going back.
3. Sub volume issues, which I experienced when not utilizing DIRAC.
Mixed bag for sure. There’s a few changes I want to make in my system. Changing this component is low on the priority list at the moment. I purchased for around $1100 refurbished. Unsure if it’s worth $2k. I think I would have said it’s worth it if I hadn’t been a little frustrated with DIRAC at the moment - probably user error to be honest.