Parasound Halo JC3+ MM/MC Phono Preamplifier

Dual mono circuitry designed by the legendary John Curl, and board layouts by Carl Thompson.

The Parasound Halo JC3+ phonostage offers MM or MC support with single-ended input only, and single-ended or balanced output. A mono switch can improve the sound of mono LPs. Variable MC impedance can be adjusted between 50 and 550 Ohm.

The Upscale View

Parasound is one of the industry's low-key, high-return brands. It's not always the first name on a customer's lips, yet is a hugely respected and loved brand by people who work in high-end audio. This isn't just because of the legendary John Curl who is behind most of its top-flight designs, but also because Parasound uses such expensive and solid engineering, yet is able to price its products so reasonably. Parasound is the brand of choice for someone who really knows good sound, but doesn't have the budget for audio jewellery.

Another John Curl Classic

Designed by John Curl—the creator of the legendary Vendetta Research phono preamp—this phonostage is built around a true dual-mono topology. Each audio channel is physically separated and enclosed in its own extruded aluminum housing, with independent high-speed soft-recovery rectifiers, filter capacitors, and voltage regulators for left and right channels. Triple shielding and low-carbon mild-steel partitions isolate the power supplies and AC wiring from the audio circuits, contributing to RIAA accuracy specified within 0.2 dB.

Signal integrity is reinforced through deliberate component and connector choices. The audio path uses Vishay-Dale resistors. Inputs and unbalanced outputs are handled by Vampire 24k gold-plated RCA jacks, while balanced outputs use premium Neutrik XLR connectors. Loading options cover MM at 47 kΩ, MC at 47 kΩ, or variable MC loading adjustable from 50–550 Ω. A mono switch is provided to improve playback of mono and older LPs.

Attention is also paid to power and system integration. A built-in AC line noise conditioning circuit helps prevent mains interference from entering the audio stages, and an AC polarity reverse switch can reduce hum in certain system configurations. A non-magnetic aluminum rear panel is used to avoid magnetic interaction near signal connections. Turn-on behavior can be set to manual or automatic operation via a 12 V trigger input. Power is supplied through a premium detachable heavy-gauge IEC AC cord, and the 2U chassis is rack-mountable using the optional HRA2 kit.

The Finest Components

Only the finest components are used, with Vishay-Dale resistors in the audio path, Vampire 24k gold-plated RCA jacks, and Neutrik XLR connectors.

A triple shield separates power supply and audio circuits, and the design is fully dual mono. The rear panel is also aluminum. The power supply uses high-speed soft recovery bridge rectifiers and common-mode inductors.

Specifications

Inputs: Stereo RCA, 12 V trigger

Outputs: Stereo RCA, stereo XLR

Input Impedance
MM or MI: 47k Ω
MC: 50- 550 Ω

Output Impedance
Unbalanced: < 100 Ω
Balanced: < 100 Ω per leg

Input Capacitance: 150 pF

Gain (MM, MC): 48 dB, 64 dB

Dimensions (WHD): 17-1/4" x 4-1/8" x 13-3/4"

Weight: 19 lb.