Parasound Halo JC 1 monoblock power amplifier Page 2

Setup and Use
In its unusually detailed instruction manual, Parasound recommends using the Halo JC 1 in balanced configuration. But my Hovland HP-100 preamplifier is single-ended, so that's how I used the Halos, with their Bias Level switches set to High, which configures the amp's output stage to operate at up to 25W in class-A. I placed the JC 1s on a pair of Finite Elemente Pagode amplifier stands and plugged them into the Shunyata Research Hydra power distribution center with Anaconda AvX power cord. I used both Harmonic Technology Fantasy 10 and Wireworld Silver Electra AC cords.

When plugged in, the amp's red light glows faintly, as does a blue halo around the front-mounted On/Off switch. On power up, the halo glows red before once again glowing blue, but more intensely. The red light also glows more brightly. The problem with this arrangement is that it's not easy to tell if the amp is on or off, since it's difficult to remember the relative levels of light coming from the red and blue lights in each mode. But this isn't a big problem—if you touch the top plate and it's not almost sizzling hot, you know the amplifier's turned off.

The Sound of Speed, the Speed of Sound
It took but a few seconds for me to absolutely fall in love with the Halo JC 1. I first used them to drive the Kharma Midi-Grande Ceramique 1.0s, then my reference Audio Physic Avanti IIIs, which they controlled brilliantly, with the kind of relaxed ease you'd expect of a pair of powerhouse amps. If big amps are said to be slow to react, the JC 1 disproved that myth: it was lightning-fast, delivering transients and sibilants with a speed and clarity that were positively addictive.

On the UK edition of Eva Cassidy's Songbird (CD, Didgeridoo G2-10045), the vocal sibilants were cleaner and faster than I remembered them being through my reference Musical Fidelity Nu-Vista 300, itself no slouch in that department. The JC 1's ability to separate the vocal from the subtle artificial reverb, both in time and layered behind in space, was a revelation. And it was done without spotlighting or added brightness.

The overall lack of smear helped create an impressively coherent, transparent, and detailed soundstage, with the kind of air and reverberant presentation I usually associate with tubes. Reverberant trails emanating from centrally placed vocals radiated away in space farther toward the side of the stage than I remembered hearing them with my reference amp.

Audio Fidelity, a new audiophile label founded by former DCC Compact Classics head Marshall Blonstein, sent along some hybrid SACDs mastered by Steve Hoffman, including the Zombies' Greatest Hits (AFZ 001). With no previous reference for the disc, I found the sound of very familiar material (from vinyl and older CDs), decoded by Musical Fidelity's new Tri-Vista SACD player and amplified by the JC 1s, to be nothing short of stupendous. I wondered how my reference Nu-Vista 300 amp would present it, but this combo delivered tonal richness, palpable 3D images, and resolution of inner detail that had me cranking up the volume to ridiculous levels without sacrificing any of the picture's intense delicacy. Cymbal strokes rang with convincing shimmer, free of unnatural grain, grit, and hardness, and vocals had that "in front of the microphone" dimensionality that makes you feel as if you're in the studio instead of on the receiving end of a recording.

The bottom end was equally impressive and subtly drawn. I expect extension and definition from a solid-state amplifier, but what I often hear is bass that's overdamped, overly constrained, and mechanical. Not with the JC 1—though for this I had to wait until my Avanti IIIs were reinstalled in the system. The Kharma Midi-Grandes' lack of bass definition—at least in my room—limited my ability to draw any conclusion about the amp's bass response.

Classic Records' long-awaited 200gm Quiex SV-P pressing of Norah Jones' Come Away with Me (Blue Note/Classic JP 5004) arrived after the JC 1s were installed. The presentation of this superbly recorded disc left nothing to be desired. No doubt the amp remained in class-A operation throughout this acoustic set, which may have contributed to the combination of speed, liquidity, delicacy, transparency, and intoxicatingly creamy purity that had me listening to Jones' unique jazz-country stylings over and over. When she sings "Come away with me," I want to go! The focus and three-dimensionality of her voice on that title track, combined with brilliant integration of the head/body continuum and the absolutely smear-free delivery of most sibilants, and aided by a daringly dry and close-up recording, constituted one of the most convincing re-creations of the female voice I've heard at home.

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James Trower's picture

Parasound JC1 power amplifier comparison to the newer Parasound JC1+ power amplifier.

I have owned many amplifiers over the years; I am saying 30 or more. I have had small 75 watt amps to much more powerful 500 watt amplifiers.
I bought the JC1 amplifiers in 2004. I had read many positive reviews such as this one in Stereophile.
Upon a few weeks of listening; I honestly thought there was a problem with them. The bass was so deep, and textured, I thought something was amiss.
The dynamic swings were on a level that shocked me. The ability to go to very high volume levels, without sounding like the volume had changed. They just would not distort at ridiculously high levels.
The bass issue still bothered me. I thought part of the circuitry had malfunctioned, and was causing bass that did not exist in the music. It just seemed too present, deep and growly.
I changed speakers, as I have no tone controls in my system. The same; just amazing dynamics, crystal clear high volume levels and truly amazing bass.
It took me a bit. It was the fact the JC1's provided a huge amount of current.
I had also read many reviews stating the bass was phenomenal. I was satisfied they were not malfunctioning.
I did quite a few comparisons to amplifiers reviewed and bench tested in Stereophile. I found that the maximum dynamic output of this amp is hard to beat by any amplifier tested.
Then came the review of the new Parasound JC1+. The bench test measurements for the JC1+, even though it is rated at 450/Watts (50 more than the JC1), showed quite a bit less maximum power into 8/4 and 2 ohms.
The maximum power output was:
The JC1 - 8/4/2 ohms power output was 586/1154/2255 and 4200 watts into 1 ohm.
The JC1+ - 8/4/2 ohms power output was 500/830/1200 and no testing into 1 ohm.
I think this very high output from the Parasound JC1 was responsible for the exceptionally deep base and very large swings in dynamics. I think it also has very amazing detail and imaging.
If you can find a pair (usually around $5000) grab them. They get an A rating from me on my 20 year listening quest.