Halo JC-1, Part 2
The monoblocks are full broken-in now and I am in my new location, with a much larger room to audition them. I installed a single dedicated 20-amp circuit for all of the grounded equipment using 10-gauge copper ROMEX - almost 45 feet long. Ungrounded equipment uses another circuit. No ground-loops here - dead quiet. The amps are dead-quiet too, with one exception. When I tried to connect the home-theater to them (including CATV), I got a noisy 60Hz hum that got somewhat better when I used the ground-lift switches, but was still unacceptable. The interesting thing is that with my other amp, the CODA 10.5, the front channels are dead-quiet. Must be the difference in steady-state current that is being drawn by the JC-1's. In any case, I will need an isolator for the CATV ground if I am to use the JC-1's for home theater.
I finally replaced the stock PC's with my own Grand Slams in 3-foot lengths. This improved the detail quite a lot. The latest thing I tried was to change the pre to JC-1 IC's from SE to balanced. This made a significant difference in imaging, dynamics and detail. Particularly, the venue reflections are now very obvious. The system is now rivaling the very best I have heard, including the WAVAC/Ceramique system at Dave Robinson's (Positive-Feedback). The only weak-point is now the speakers, which I will be modding this summer. The system currently looks like this:
Source: Modified Sony DVP-S7700 transport
Source to DAC cable: Bitmeister Digital 0.5m
DAC: Modified Perpetual Technologies P-3A and P1A
DAC to Pre cable: Holophonic-PC 1m
Preamp: Highly modified Mark Levinson #38
Pre to amp cables: Holophonic-XPC 1m
amps: Parasound JC-1 monoblocks
amp to speaker cables: Clarity 7 6 footers
speakers: KEF 104/2
After playing a lot with different passive line-stages, my Proceed AVP and my hot-rodded Levinson #38, I have come to the conclusion that these amps are very sensitive to the pre that is driving them This is eluded-to in the various reviews from BFS, Stereophile and TAS. They really open-up and have great dynamics when driven from a low output-impedance pre, such as the ML #38. They are a bit flat and lifeless with passive pre's in comparison.
I did notice some changes with break-in, but nothing like what was written by Marty in BFS. After 2 weeks to a month, they sound perfect.
I am a very happy camper now and have no regrets about purchasing the JC-1's. Highly recommended.