About the Parasound Halo JC 3+
Refined, powerful phono preamp
Refined, powerful phono preamp
Parasound's JC 3+ brings out warm, rich detail in your vinyl, above a near-silent noise floor. This is Parasound's best phono stage, and it's an improvement over its predecessor, the JC 3, which was itself famously well-regarded in high-end audio circles. You can make the most of your moving magnet or moving coil cartridges by using the left- and right-channel 3-way gain selection switches — with knob-controlled adjustments for moving coil cartridges. And you get balanced and unbalanced outputs for connecting to your favorite amplifier.
Strong, silent type
Elegant design under the JC 3+'s hood shows dual mono circuitry in discrete aluminum enclosures, and low-carbon steel partitions isolating the power supply.
Everything about the Parasound JC 3+'s topology tends toward a dead-silent background. Each channel is isolated inside its own aluminum enclosure. The R-core transformer has the advantages of low noise, low loss, and high efficiency. There's even a built-in AC line conditioner.
Parasound brought its A-team to create the JC 3+. John Curl's elegant circuit design, Carl Thompson's efficient circuit board designs, and Bob Crump's premium internal component choices all work toward the same goal — vanishing noise.
The legacy of John Curl
The JC 3+ features circuitry designed by by John Curl, a legend in audio engineering. He started his career in the 1970s, designing tape and video recorders at Ampex, and he had a hand in building the Grateful Dead's Wall of Sound. Curl has worked with Parasound since 1989, designing all of their high-power amplifiers and more. The power supply, transistors, capacitors and other parts in the JC 3+ were chosen to offer high performance at a reasonable price.
- compatible with moving magnet and moving coil phono cartridges
- dual monaural design — each audio channel separately enclosed in an extruded aluminum enclosure
- 3-way cartridge select switch for each channel:
- moving magnet: 47k ohm
- moving coil: 47k ohm
- moving coil: variable 50-550 ohms — independent knob adjustment in 10-ohm increments for each channel
- signal-to-noise ratio: 87dB (MM)/87dB (MC)
- total harmonic distortion: < 0.01% at 1 kHz
- selectable mono or stereo output
- R-core power transformer
- low-carbon steel partitions isolate power supplies and AC wires
- built-in AC line conditioner prevents AC noise
- AC polarity reverse switch can reduce hum in many systems
- 1 pair unbalanced RCA inputs
- 1 pair unbalanced RCA outputs
- 1 pair balanced XLR outputs
- 3.5mm 12V trigger input and loop output jacks
Dimensions and warranty:
What's in the box:
- Phono preamplifier
- 6' AC power cord
- 6' 2.5mm trigger cable
- 6' 2.5mm-to 3.5mm trigger cable
- Owner's Guide
More details on the Parasound Halo JC 3+
Features & specs
|Cartridge Type||MM, MC|
|Adjustable Resistance Load||Yes|
|Adjustable Capacitance Load||No|
|RCA Inputs||1 Pair|
|RCA Outputs||1 Pair|
|Signal-to-noise Ratio (MM)||87|
|Signal-to-noise Ratio (MC)||87|
Audiophile-Grade Design: The Parasound JC 3+ phono preamplifier features an audiophile-grade design with high-quality parts, contruction and implementation, so you get to experience the full emotion of your vinyl recording content.
- The phono module circuit boards are 14k gold plated for optimum electron flow. They are further protected by physically separating these critical audio signals from the non-audio circuits and non-audio wiring. Each channel has its own circuit board and each channel is fully enclosed in its own extruded aluminum "vault". This vault shields the sensitive circuits from the JC 3+’s power supply and from external sources of noise.
- The JC 3+ power supply uses a high capacity R-core power transformer. R-core transformers share the advantages of a toroid transformer for minimizing radiated hum. However, it is far superior to a toroid transformer in preventing noise carried on the AC power line from passing through to its secondary windings and into the power supply. 40,000uF of filter capacitance assures you will hear all of the dynamic contrasts that give additional life and presence to your LPs.
- A second level of shielding separates each phono vault from the power supply, power transformer and even the transformer wires running to the AC inlet on the rear panel. This shielding consists of two partitions of 3/8" low carbon steel to prevent any electromagnetic radiation from reaching the phono modules. The rear panel of the JC 3+ is made of aluminum to prevent any electromagnetic interaction with the sensitive phono circuitry.
- The JC 3+ has an on-board AC line conditioner to filter out high frequency noise and distortion that may be present on your AC power line. This eliminates a potential source of noise before it ever reaches the JC 3+ power transformer. The resulting extremely low noise levels enable musical nuances to emerge from an utterly silent background.
MM or MC Compatible: The Parasound JC 3+ phono preamplifier is compatible with turntables that are equipped with MM (moving magnet) or MC (moving coil) cartridges. There is a switch located at the back panel that allows you to select between MM (47k ohm), MC (variable), or MC (Fixed). The MM setting is fixed at 47,000 ohms, while the MC setting is variable and can be adjusted from 50 to 550 ohms. There is also a MC Fixed setting that provides an alternative fixed 47,000 ohm load for select MC cartridges.
Input Impedance Control: The JC 3+'s Input Impedance Control enables you to fine tune the input impedance for MC cartridges over a range of 50 ohms to 550 ohms. Cartridge manufacturers recommend what they consider to be an optimal load impedance. However, their spec won't necessarily give you the best results in your system. You should experiment with this control and use whichever load impedance you feel results in the best performance of your system in your listening room.
Gain Control: The Gain Control allows you to select the appropriate gain for your turntable's MM or MC cartridge. Select 40dB, 50dB, or 60dB. Whether you have an MC or MM cartridge you can experiment with which of the three gain settings gives you the best with your line stage preamp or integrated amplifier.
- 40dB: The lowest gain settings that is typically used with moving magnet (MM) cartridges.
- 50dB: For high output moving coil cartridges or low output moving magnet cartridges.
- 60dB: For low output moving coil cartridges whose output is typically less than 0.5mV.
Mono Button: Press the JC 3+'s Mono button to parallel the left and right stereo channels to mono. Press it again to return to stereo. The Mono button glows blue when stereo is selected and changes to amber when mono is selected. Older mono records and stereo records pressed with high levels of rumble will sound cleaner when you select mono on the JC 3+.
Balanced & Unbalanced Connectivity: The Parasound JC 3+ phono preamplifier is outfitted with both balanced XLR and unbalanced RCA connections. In most systems balanced XLR connections will give you the best sound.
- Unbalanced RCA Inputs: For its analog inputs, the JC 3+ phono preamplifier is equipped a set of unbalanced stereo RCA inputs. These unbalanced stereo RCA inputs connect to your turntable.
- Balanced XLR and Unbalanced RCA Outputs: For its analog outputs, the JC 3+ phono preamp is equipped with a set of balanced stereo XLR outputs and a set of unbalanced stereo RCA outputs. These balanced or unbalanced outputs connect to your line-level preamplifier or integrated amplifier. The balanced XLR outputs will provide maximum rejection of external noise sources.
Note: The balanced and unbalanced jacks are active simultaneously, but should not be used at the same time.
Ground Wire: To eliminate hum, your turntable's ground wire attaches to the JC 3+'s ground terminal that is located on the rear-panel next to the right channel XLR balanced output.
12V In/Out: The Parasound JC 3+ is equipped with a 12V trigger input (3.5mm) and output (3.5mm). The Trigger In allows the phono preamp to turn on automatically with your preamplifier or integrated amp that features a Trigger Out. The Trigger Out lets you loop or "daisy-chain" the incoming trigger voltage to another component. The JC 3+. trigger circuit draws a negligible 10mA current from the triggering device.
Optional Rack Mount: For mounting in a standard 19" equipment rack, you must use the Parasound HRA 2 rack mount kit (sold separately - see Accessories Tab). With its four feet removed, the JC 3+'s panel height occupies 2U rack spaces.