The Halo JC 2 is a pure analog preamplifier that is the product of pure genius. John Curl's CTC Builders, creators of the famed JC 1, designed the JC 2 to be Parasound's next legend. The design team achieves an amazing 116 dB signal-to-noise ratio with the JC 2 by isolating its dual-mono audio circuits from the power supply by placing them behind noise-killing 3/8"-thick shields. Balanced inputs and outputs -- featuring Neutrik XLR connectors -- a switchable polarity invert, and a full-function wireless remote control all contribute to the affordable luxury of owning a Halo JC 2.
Absolutely Dead-Quiet Operation
"The JC-2 allows music to emerge intact -- withy body, bloom, and dynamics, with definition and detail -- from an utterly silent background," reports Sam Tellig in Stereophile.
From the beginning, Parasound made quiet operation a priority of the JC 2. In fact, the company wanted this to be the quietest preamp that you can buy â at any price. Instead of relying on a toroidal transformer, which is typically found in quality AV components, the design team opted for a high capacity R-core audio power transformer and inductor with additional filters and special low-ESR capacitors. Unlike a toroidal transformer, this premium technology does not pass noise through to the rest of the circuitry, contributing to the JC 2's dead-quiet operation.
The heavily regulated dual-mono power supply boasts hyper-fast soft recovery audio bridge rectifiers diodes. And there's an independent power supply for controller, relay coils, triggers, and LEDs, an approach with keeps the preamps 'housekeeping' circuits well out of the audio chain.
"I can vouch for the results," says Alan Taffel about the ultra-quiet design in his January 10, 2007 report on the CES show for AVguide.com. "In one of the simplest but most effective demos of the show, I placed my ear directly against the driver of a speaker being fed by a JC-2/JC-1 combo set at maximum volume. I could hear absolutely nothing."
Dual-mono left and right channel circuit boards minimize crosstalk. The direct DC servo-coupled design uses no capacitors in the signal path. The premium four-gang motor-driven analog master volume control uses separate TKD brand analog gain controls for L and R channels. The audio mute is switched by independent L and R relays.
Balanced and Unbalanced Input Switching
The JC 2 includes six pairs of unbalanced RCA line-level audio input jacks. Two input pairs can be switched to XLR balanced connectors. There's an independent balanced/unbalanced select for the left and right channel, and each channel's input is switched by its own gold-on-silver contact relay.
Separate output jacks are provided for simultaneous normal and non-inverting polarity. The four output jack pairs have specialized functions. One main output jack pair is balanced XLR, and the polarity can be switched by the wireless remote. One main output jack pair is unbalanced RCA, and polarity is also switched by remote. Of the two remaining outputs, one pair is unbalanced RCA, inverted polarity only, and the other output pair is unbalanced RCA, normal polarity, featuring a fixed level for recorders. Remote control polarity switching uses gold-on-silver contact relays.
Hand-Picked, No-Compromise Parts and Pieces
Every section of the JC 2 uses premium internal components that were specifically chosen for specific functions in specific areas. These include hand-matched, complementary input-stage and output-stage FETs, Vampire brand 24k gold-plated RCA jacks, Neutrik brand premium XLR connectors, and Canare brand internal wiring.
The rear panel of the JC 2 is made of aluminum, for less magnetic impact on the ground plane and the signal jacks. And speaking of those connections, all grounding for the JC 2's inputs is completely isolated from all grounding for the outputs.
The included wireless remote controls all functions using discrete IR codes. A two-way RS-232 serial port connection and 12-volt trigger systems allows for easy system integration. Four 12v trigger output jacks allow for power amp auto turn-on. Two 12v trigger jacks are switched by the remote, and two 12v trigger jacks are live when the JC 2 is turned on.
6 pairs unbalanced RCA line-level audio input jacks 2 input pairs can be switched to XLR balanced connectors Independent balanced/unbalanced select for the L & R channel Each channelâs input is switched by its own gold-on-silver contact relay 4 output jack pairs with specialized functions: 1 Main output jack pair is balanced XLR, polarity is switched by remote 1 Main output jack pair is unbalanced RCA, polarity is switched by remote 1 output jack pair is unbalanced RCA, inverted polarity only 1 output pair is unbalanced RCA, normal polarity, fixed level for recorders Dual-mono left & right channel circuit boards minimize crosstalk Hand-matched complementary FETs Direct DC servo-coupled, no capacitors in the signal path Premium 4-gang motor-driven analog master volume control Separate TKD brand analog gain controls for L & R channel 3/8" thick aluminum shielding around audio boards Shielding prevents noise from power supplies & control circuits Separate output jacks for simultaneous normal & non-inverting polarity Aluminum chassis rear panel Remote control polarity switching uses gold-on-silver contact relays Vampire brand 24k gold-plated RCA jacks Neutrik brand premium XLR connectors Canare brand internal wiring High capacity R-core audio power transformer & inductor Hyper-fast soft recovery audio bridge rectifiers diodes Independent power supply for controller, relay coils, triggers, LEDs Remote control handset controls all functions Discrete IR codes for remote control Four 12v trigger output jacks for power amp auto turn-on: Two 12v trigger jacks are switched by the remote handset Two 12v trigger jacks are live when the JC 2 is turned on Two-way RS-232 serial port connection Line level inputs only; no inputs for phono Audio mute is switched by independent L & R relays Rear panel IR repeater input & loop out jacks Premium detachable heavy gauge IEC AC cord 2 6â (2m) trigger wires included Remote handset also controls Parasound Halo T 3 Tuner 3u Chassis, rack mountable with HRA3 (sold separately) Parasound 5 year parts, 5 years labor warranty (For USA and Canada purchases only)
HomeTheaterReview.com, February 2010
If you're an audiophile, you almost certainly know of the Parasound company, a manufacturer of high-end audio/video electronics (and other products) that are of extremely high quality, yet are not stratospherically priced. Halo is Parasound's premium line of components. (The JC 2 is not inexpensive at $4,000, but this is a high-end component we're talking about, and for what you get, that can be considered good value.) You might also know of John Curl, a veteran audio designer who is inarguably one of the true greats in the field. Curl has worked for esteemed companies like Mark Levinson, Vendetta Research, Harman Kardon Citation, Wilson Audio and others, and even worked on electronics for the Grateful Dead. Curl has been a consultant to Parasound since the late 1980s.
Stereophile, March 2008
POSITIVE FEEDBACK ONLINE - ISSUE 34 (Max Dudious)
Frequency Response 5 Hz - 100 kHz, +0/-3 dB Distortion THD: < 0.003% at 100 Hz THD: < 0.005% at 20 kHz IM: < 0.003% S/N Ratio > 116 dB, input shorted, IHF A-weighted > 104 dB, input shorted, unweighted Crosstalk > 100 dB at 10 kHz > 90 dB at 20 kHz Gain 14 dB, maximum L, R Gain Control Range - 10 dB Input Impedance Unbalanced: 30k ohms Balanced: 30k ohms per leg Output Impedance Unbalanced: < 60 ohms Balanced: < 60 ohms per leg Input Sensitivity 200 mV for 1 V output Total Gain: 14 dB Maximum Output: 8 V XLR Pin Identification 1 = Ground (Shield) 2 = Positive 3 = Negative (Return) AC Power Requirement 110 - 120 V or 220-240 V, 50 - 60 Hzs (Set AC Voltage switch on rear panel) 25 watt standby; 30 watts when turned on Dimensions Width: 17 1/4" (437 mm) Depth: 16" (406 mm) Height, with feet: 5 7/8" (150 mm) Height, without feet: 5 1/4" (133 mm) Weight Net: 24 lbs. (11 kg) Shipping: 36 lbs. (16.4 kg) Rack Mount Accessory HRA 3 (May be purchased separately)