JC 1+ Mono Power Amplifier by John Curl
Halo
JC 1+
Changes from the JC 1 to JC 1+
Read the JC 1+ development story here
- 400 → 450 Watts @ 8Ω
- 800 → 850 Watts @ 4Ω
- 1200 → 1300 Watts @ 2Ω
- Filter capacitance: 132,000 → 198,000 uF
- Transformer capacity: 1.9 → 2.1 kVA
- Output transistors: 18 → 24 Sanken 60Mz devices
- Peak current: 135 → 180 amps
- Weight: 64 → 83 lbs net
- Bybee Music Rails™ active high frequency noise filters
- John Curl driver stage employs a new cascode circuit design
- FR-408 input circuit board material improves HF signal integrity
- Gain switch to select 29 dB or 23 dB of gain
- R-core power transformer for input stage
- Input circuit board is shielded
- Double thickness copper on output/power supply circuit boards
- Gold-plated internal audio signal path connectors
- Custom CHK Infinium speaker binding posts
- Looping Neutrik XLR output for easier bi-amping
- Front panel power indicator LED
- Updated auto turn on circuits with 3.5mm 12V trigger jacks
- Circuitry designed by legendary John Curl
- Ultra-high bias Class A/AB operation
- 25 watts of pure Class A power
- Stable with speaker impedance dips below 1Ω
- Bybee Music Rails™ - active high frequency filters for input stage
- New John Curl driver stage employs a cascode circuit for greater open loop bandwidth & superior linearity
- Gain switch to select 29 dB or 23 dB gain for optimum compatibility with high gain preamps or extremely efficient speakers
- R-core transformer for input stage suppresses noise on power line
- 6 massive 33,000 uF Nichicon Gold Tune filter capacitors for output stage
- 22,400 uF input stage power supply filter capacitors, independent of the main power supply
- Dual CHK Infinium, custom 5-way speaker binding posts for easy bi-wiring
- Neutrik locking XLR balanced input & loop output jacks
- Vampire 24k gold-plated RCA input & loop output jacks
- Direct-coupled signal path, no capacitors or inductors in the audio path
- JFET input stage, MOSFET driver stage
- 24 beta-matched 15 ampere, 230V, 60 MHz bipolar output transistors
- 2.1 kVA shielded toroid power transformer with premium H18 grade core
- Independent power supplies for input stage, driver stage & output stage
- Full power is rated all the way down to 2Hz for unrestricted low-end bass
- Harris hyper-fast soft-recovery bridge diode rectifiers
- REL & Nichicon Muse capacitors
- DC servo & relay protection circuits
- AC turn-on inrush surge protection with relay bypass
- Automatic turn-on by 12 V trigger or audio sensing
- 4 rack space chassis with rear carry handles
- Rack mount hardware is included
- Available in silver or black
All Features:
Power Output
450 x1 watts @ 8 Ω
850 x1 watts @ 4 Ω
1300 x1 watts @ 2 Ω
Power measurements are with 120 VAC:
0.15% THD, RMS continuous power,
full audio band (20 Hz - 20 kHz)
Class A Power Output
25 Watts, bias switch set to high
10 Watts, bias switch set to low
Current Capacity
180 amps, peak
Slew Rate > 130 volts per microsecond
Frequency Response
2 Hz - 120 kHz, +0/-2 dB
20 Hz - 20 kHz, +0/-0.25 dB
Total Harmonic Distortion (THD)
< 0.15 % at full power
< 0.02 % at typical listening levels
IM Distortion
< 0.03 %
TIM
Unmeasurable
Damping Factor
> 1200 at 20 Hz
Input Impedance
Unbalanced: 50 kΩ
Balanced: 100 kΩ, (50 kΩ per leg)
S/N Ratio, inputs shorted
>122 dB, IHF A-weighted, bias set to Low
>120 dB, IHF A-weighted, bias set to High
>113 dB, Unweighted, bias set to Low
>111 dB, Unweighted, bias set to High
Total Gain
29 dB (Gain switch set to normal)
23 dB (Gain switch set to low)
Input Sensitivity for 28.28 V Output into 8 Ω
Unbalanced: 1 V
Balanced: 1 V per leg
(Gain switch set to normal)
DC Trigger Requirements
+9 Vdc to +12 Vdc, 5 mA
Audio Trigger Requirement
2.5 mV - 10 mV
XLR Pin Identification
1 = Ground (Shield)
2 = Positive
3 = Negative (Return)
Dimensions
Height without feet: 7-1/8" (181 mm)
Height with feet: 7-3/4" (197 mm)
Depth: 20" (508 mm)
Depth with cables: 21-1/2" (546 mm)
Shipping Carton Dimensions
Width: 29-1/2" (750 mm)
Depth: 27-1/2" (700 mm)
Height: 15-3/4" (400 mm)
Net Weight
83 lb. (37.6 kg)
Shipping Weight
107 lb. (48.5 kg)
Power Requirement
Standby: <1 Watt
Idle (bias set to low): 145 Watts
Idle (bias set to high): 275 Watts
Typical Listening levels: 400 Watts
Maximum: 1500 Watts
TheAbsoluteSound.com, August 2022
TAS recommends power amplifiers in the $10K-$20K MSRP price range
PARTTIME AUDIOPHILE BEST AMPLIFIERS, SUMMER 2022 GUIDE—
Parasound JC 1+ Monoblocks ($9499 each USD)
"The first update from Parasound on the 20-year-old JC 1s, the Plus is Richard Schram and John Curl's effort to make a worthy successor that will stand the test of time. Powerful, clear and quite a lot of value when you compare it to more esoteric monsters, the JC 1+ is very neutral. "There was no major sense of lack of color or excitement, they simply tell a speaker to move like the music moves," we observed."
Tone Audio, October 2021
"I have yet to hear a pair of solid-state amplifiers that offer anywhere near this much sonic excellence and sheer power for anywhere near the price of these amplifiers. If someone whispered in my ear, "you're listening to a six-figure pair of amplifiers," I would believe them. The JC 1+ monos are that good, that refined, that musical."
Hi Fi Review (Hong Kong), August, 2021
"Even the harmonics and the hall ambiance have a vivid sensation and benefit from the JC 1+ lack of background noise. To let the sound and music in the signal appear more detailed and exquisite, picturing details of this solo violin recording are richer, and the interpretation is like constructing a more three-dimensional Zen garden and more encompassing."
The Absolute Sound, June 2021
"No doubt you can spend a lot more money on amplifiers ranging from $50,000 and up, and I'd be the last to dissuade anyone from chasing audio rainbows as vigorously as they please. The gains will be there in tonality, dynamics, and filigree of detail, particularly in the treble. But the JC 1+ monoblocks come so darned close to the best, in so many categories, that for more than a few listeners it may seem an otiose pursuit to look elsewhere. Parasound and John Curl deserve a rousing round of applause for producing a real-world-priced amplifier that delivers otherworldly sound."
Stereophile (John Atkinson), May 2020
"With JC 1+ amplifiers, the feeling of listening to a Steinway D in a real space was very satisfying. High frequencies were smooth and clean, more like what I experience from a good tube amplifier. Dynamics were extraordinary. Low-frequency power and delicacy! The improvement in its sound quality and the recent explosion of the prices of high-end, high-power amplifiers keep the JC 1+ competitive. This is a superb-sounding amplifier that will get the best from every loudspeaker with which it is partnered. Well done, Mr. Curl."
Manufacture Comments to the Stereophile Review
Secrets of Home Theater & High Fidelity (John Johnson), June 2020
"Parasound has long been admired for their preamplifiers and power amplifiers. The JC 1+ power amplifier is truly an achievement to the highest degree. The sound is exemplary and reflects its amazing design, while parts quality is a statement on its own. Proof of Performance for the Parasound has been verified. They are worth the price."
Positive Feedback May 2020
"I cannot think of a pair of monoblocks that offer a view anywhere near this close to the top of the heap for anywhere near their asking price. I can tell you that if I were shopping for a pair of monoblocks under $25,000, the Parasound Halo JC 1+ would be my first choice. Go give these new over-achievers a listen and be prepared to be bowled over by what you will hear. Most enthusiastically recommended."
