JC 1+ Mono Power Amplifier by John Curl Halo

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

All Features:

• 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

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