Parasound Halo JC3+ Phono Preamplifier
The desire to have a great phono pre-amplifier for any dedicated audio manufacturer is paramount, and Parasound were no exception to this rule.
Some time ago the legendary audio designer John Curl was asked by Parasound if he would create a reasonably priced Halo phono pre-amplifier in the spirit of his masterpiece, the Vendetta (Research). Three years later they introduced the remarkable Parasound Halo JC 3 - which then earned rave reviews from the audiophile press and a legion of vinyl enthusiasts. During the design phase of the original JC 3, Curl had rejected variable load adjustment because potentiometers generally have higher thermal self-noise, which is an anathema to the creation of an ultra low noise phono stage.
The decision to bring the JC 3 to market with limited switched input load impedance choices disappointed some vinyl enthusiasts who consider input load fine-tuning to be essential for certain cartridges. Curl and circuit board designer Carl Thompson eventually consented to a 'redesign' with variable load impedance adjustments, but with these caveats for the potentiometers. The first consideration was that they must comply with stringent performance requirements, and the second key factor was that they must be manufactured by Vishay, a highly-regarded manufacturer of low-noise component parts.
Curl and Thompson took this opportunity to make additional performance improvements. Curl has narrowed the spectrum of Johnson/Nyquist noise in the resistor that loads the input stage. Circuit-board designer Carl Thompson tweaked the phono module board layouts to further optimize every performance parameter. The phono modules copper circuit board traces now have 24 karat gold-plating where each part is soldered to provide exceptional transparency and musical detail.
As a result of these changes, the MC signal to noise ratio is improved to 87dB, A-weighted. MM gain has been increased slightly to 48dB, while MC gain has been lowered from 68dB to 64dB so that extra-high output MC cartridges won’t cause the JC 3+ to overload the inputs of some line stage preamps or integrated amps. The JC 3+ power supply has also been significantly upgraded with 47 percent larger low-ESD power supply filter capacitors and an 82 percent larger R-core power transformer. This provides much greater current reserves for head-snapping dynamics.
The clever dual mono design (each audio channel is separately enclosed in its own extruded aluminium enclosure) minimises any hint of harmonic distortion and the separate high speed-soft recovery rectifiers, filter caps and voltage regulators for each channel underlay the dedication to maintaining the purest signal retention. These internal markers are coupled of course with external features and benefits that you'd expect from a manufacturer like Parasound, as the quest for audio purity is seen even in the non-magnetic aluminium rear panel for purest sound.
The unit's physical appearance and construction is exemplary as the rest of the Halo series are, which can even be seen in every element - and in that point as a final nuanced design touch, they added an on/off switch for the front P logo illumination.
With the resurgence in vinyl, the format that has never been obsolete (unlike so many pretenders to the throne), the JC3+ is like the format itself; an evolved (not revolving) masterpiece that can never be left behind.
The Parasound Halo JC3+ is available in black and silver finishes - please specify on order.
Parasound Halo JC3+ Phono Pre-Amplifier Features & Benefits:
Inputs and outputs use Vampire brand 24k gold-plated RCA jacks
Balanced outputs use Neutrik brand premium XLR jacks
MM 47k ohm, MC 47k ohm or MC variable 50-550 Ohms
RIAA accurate within 0.2 dB
Exclusively Vishay-Dale resistors in the audio path
Triple shielding; low-carbon mild steel partitions isolate the power supplies & AC wires
Dual mono design; each audio channel is separately enclosed in its own extruded aluminum enclosure
Separate high speed-soft recovery rectifiers, filter caps and voltage regulators for each channel
Superior R-core type power transformer
Mono switch can improve sound of mono and older LPs
Built-in AC line conditioner to prevent AC noise from polluting the circuits
AC polarity reverse switch can reduce hum in many systems
Non-magnetic aluminum rear panel for purest sound
Turn On Options switch: manual or auto with 12v trigger input
Premium detachable heavy gauge IEC AC cord
2u Chassis, rack mountable with HRA2 (sold separately)
Parasound Halo JC3+ Phono Pre-Amplifier Specifications:
20 Hz - 20 kHz, +/- 0.2 dB
Total Harmonic Distortion:
< 0.01% at 1 kHz
Signal to Noise Ratio, MM:
> 87 dB, input shorted, IHF A-weighted
> 78 dB, input shorted, unweighted
Signal to Noise Ratio, MC:
> 87 dB, input shorted, IHF A-weighted
> 67 dB, input shorted, unweighted
72 dB at 1 kHz
MM: 47k Ω
MC: 50 - 550 Ω variable, 47k Ω fixed
Unbalanced: < 100 Ω
Balanced: < 100 Ω per leg
Input Sensitivity at 1 kHz:
MM: 4mV for 1 V output
MC: 600ÂµV for 1 V output
MM: 48 dB
MC: 64 dB
XLR Pin Identification:
1 = Ground (Shield)
2 = Positive
3 = Negative (Return)
AC Power Requirement:
Standby: 1 watt
Power On: 12 watts
115 or 230 VAC 50 - 60 Hz
(Selected on Chassis Bottom)
Width: 17-1/4" (437mm)
Depth: 13-3/4" (350mm)
Height, with feet: 4-1/8" (105mm)
Height, without feet: 3-1/2" (89mm)
Net: 19 lbs. (8.6 Kg)
Shipping: 26 lbs. (11.8 Kg)
Rack Mount Accessory:
HRA 2 (may be purchased separately)