Parasound Halo JC 1+ Mono Power Amplifier

Four Hundred and Fifty Watts, One Channel

The JC 1+ is John Curl's flagship monoblock for Parasound, and the update that followed the original JC 1. Each chassis drives one speaker with 450 watts into 8 ohms, 850 into 4 and 1,300 into 2 ohms.

Those numbers came from real changes rather than a new badge. Parasound raised the output transistor count from 18 to 24, the transformer from 1.9 to 2.1kVA, filter capacitance from 132,000 to 198,000 microfarads, and peak current from 135 to 180 amps.

A front-panel bias switch sets how much of that runs in pure Class A: 25 watts on high or 10 on low. Most listening happens well inside 25 watts, so the switch decides how much of your evening the amplifier spends in its cleanest mode.

This listing carries new, open-box and used stock in black, and new in silver. Each is a single amplifier, so a stereo system needs two. Pick the finish and condition you want at checkout.

Inside the Chassis

The Output Stage

Twenty-four beta-matched bipolar output transistors per chassis, each rated 15 amps and 230 volts, sit behind a 2.1kVA shielded toroidal transformer with a premium H18 grade core. The signal path is direct coupled, with no capacitors or inductors in the way.

Three Separate Power Supplies

The input stage, driver stage and output stage each get their own supply. Six 33,000 microfarad Nichicon capacitors serve the output stage, and a separate R-core transformer feeds the input stage specifically to keep mains noise away from it.

On the Bench

Damping factor is above 1,200 at 20Hz, which is what holds a woofer still. Distortion is under 0.02% at typical listening levels, signal-to-noise better than 122dB, and frequency response reaches from 2Hz to 120kHz.

Connections and Control

Neutrik locking XLR and Vampire 24k gold-plated RCA inputs are both fitted, each with a loop output. A gain switch selects 29dB or 23dB. Dual CHK Infinium five-way binding posts make bi-wiring straightforward.

Who Is This Mono Amplifier Best For?

• Owners of speakers that fall to 2 ohms — 1,300 watts into 2 ohms and 180 amps of peak current mean the hardest part of the impedance curve stops being the limit, so the speaker sounds consistent across the whole range.
• Listeners who want Class A most of the time — Twenty-five watts of pure Class A on the high bias setting covers the level most people actually listen at, so you spend the evening in the amplifier's best operating region.
• Anyone chasing a genuinely silent background — Signal-to-noise better than 122dB, three separate power supplies and an R-core transformer on the input stage mean quiet passages stay quiet and low-level detail survives.
• Systems that need long balanced runs — Neutrik locking XLR inputs with loop outputs let you site each amplifier at the speaker and run balanced cable back to the preamp without hum or a lost connection.
• Each listing is a single amplifier — A JC 1+ drives one speaker, so a stereo system takes two. If you would rather have both channels in one chassis, the Halo JC 5 and A 21+ sit in our Stereo Amplifiers.

How Does It Connect to Your System?

Run one balanced or single-ended cable from your preamp to each amplifier, then a single speaker cable from each amplifier to the speaker beside it. Set the gain switch to 29dB or 23dB depending on how much output your preamp makes.

A DC trigger input takes 9 to 12 volts, and there is an audio-sensing trigger as well if your preamp has no trigger output. Choose the bias setting once you know how warm you want the amplifiers running.

Pairs Well With

A JC 1+ pair is the center of a system. These are the usual partners.

• Preamplifiers — a balanced preamp gets the most from the Neutrik XLR inputs. Browse preamplifiers.
• Balanced interconnects — two XLR runs, one per amplifier. Browse interconnect cables.
• Speaker cables — dual binding posts per chassis make bi-wiring easy. Browse speaker cables.
• Floorstanding speakers — the 2-ohm rating suits the most demanding designs made. Browse floorstanding speakers.

Frequently Asked Questions

How much power does one make?

Each JC 1+ delivers 450 watts into 8 ohms, 850 watts into 4 ohms and 1,300 watts into 2 ohms. Parasound rates those as continuous RMS power across the full 20Hz to 20kHz band at 0.15% distortion.

What changed from the original JC 1?

Output went from 400 to 450 watts into 8 ohms, output transistors from 18 to 24, the transformer from 1.9 to 2.1kVA, filter capacitance from 132,000 to 198,000 microfarads and peak current from 135 to 180 amps.

What does the bias switch do?

It sets how much power runs in pure Class A before the amplifier moves into Class AB. High gives 25 watts of Class A and runs warmer, low gives 10 watts and runs cooler. Rated output is the same either way.

How many do I need?

One per speaker, so a stereo system uses two. Each chassis has its own transformer and supplies, which is the reason to choose monoblocks over a single two-channel amplifier.

How big and heavy is it?

Each amplifier is 17-5/8 inches wide, 7-3/4 inches tall on its feet and 20 inches deep, and weighs 83 pounds. Allow extra depth for cables, and plan on help when you install them.

What warranty does it carry?

Parasound covers a new JC 1+ with a five-year parts and labor warranty for the original owner. Open-box and used units carry a limited warranty instead, so call us at 800-942-0220 and we will confirm what applies to the condition you choose.

See It in Action

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Learn More

Want to learn more about mono amplifiers, Class A bias, or matching an amp to your speakers? Visit our Learning Center for guides, tips, and expert advice.