Parasound Halo JC1+ Mono Power Amplifier

Parasound’s legendary Halo JC1 Monaural Amplifier was quite possibly one of the world’s finest power amplifiers. The paramount culmination of acclaimed audio designer John Curls' (and the team at CTC Builders) knowledge and expertise - so it's disappearance from the Parasound line up did raise some valid questions back in 2018.

The JC1 was in situ for such a period - and left unfettered by any significant revisions - with the testament that it could not be 'appropriately' enhanced, so it's fading into the background was in certain respects incongruous. There was of course good reason for this (as there usually is with Parasound), as reason and justification for 'appropriate' action was in fact indeed in hand. Key Changes from the JC 1 to JC 1+

• 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

Parasound Halo JC1+ Monoaural Power Amplifier - Features & Benefits:

• 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

Parasound Halo JC1+ Monoaural Power Amplifier - Specifications: 

• 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)
• Power Requirement:
  - Standby: - Idle (bias set to low): 145 Watts
  - Idle (bias set to high): 275 Watts
  - Typical Listening levels: 400 Watts
  - Maximum: 1500 Watts
• 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)
• Net Weight: 83 lb. (37.6 kg)