JCM250 Mono Power Amplifier
John Curl
JCM250
Read the JC 1+ family development story here
- 250 Watts @ 8Ω
- 450 Watts @ 4Ω
- 800 Watts @ 2Ω
- Peak current: 100 amps
- Weight: 42 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
- 5 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
- 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
- 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
- 2 rack space chassis with rear carry handles
- Rack mount hardware is included
- Available in black
All Features:
Power Output
250 x1 watts @ 8 Ω
450 x1 watts @ 4 Ω
800 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
8 Watts, bias switch set to high
4 Watts, bias switch set to low
Current Capacity
100 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
Input Impedance
Unbalanced: 50 kΩ
Balanced: 100 kΩ, (50 kΩ per leg)
S/N Ratio, inputs shorted
>120 dB, IHF A-weighted, bias set to Low
>118 dB, IHF A-weighted, bias set to High
>110 dB, Unweighted, bias set to Low
>108 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: 3.5" (89 mm) 2U
Height with feet: 4.125" (105 mm)
Depth: 20" (508 mm)
Depth with cables: 21.5" (546 mm)
Net Weight
42 lb. (19.1 kg)
Shipping Weight
50 lb. (22.6 kg)
Power Requirement
Standby: <1 Watt
Idle (bias set to low): 125 Watts
Idle (bias set to high): 240 Watts
Typical Listening levels: 300 Watts
Maximum: 800 Watts
