J+4™ Specifications

The Radial J+4 is a stereo preamplifier designed to boost unbalanced instruments and consumer level signals and bring them up to a professional +4dB balanced line level. Careful attention has been paid to delivering quality audio while incorporating transformer isolation for added noise suppression. The J+4 delivers a performance that is as good or better than devices costing many times more.


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Audio Circuit Type:  Active -10dB ~ +4dB line converter, transformer isolated
Number of Channels: Stereo
Frequency Response:  20Hz ~ 20KHz (± 2dB)
Dynamic Range:  102dB 
Maximum Input:  +17dBu @ 1kHz, 1% THD+N 
Maximum Output Level: +15dBu @ 1kHz, 1% THD+N
Total Harmonic Distortion:  0.004% @ 1kHz, +10dBu output
Phase Deviation:  0.5° @ 100Hz; 4° @ 20Hz 
Input Impedance:  10k Ohms, unbalanced 
Output Impedance:  1.6k Ohms, balanced 
J+4 Transformer: Radial custom transformer
High Pass Filter:  -3dB @ 100Hz (12dB.Oct.)  
Ground Lift:  Disconnects XLR pin-1 at isolated output 
XLR Configuration:  AES standard (pin-2 hot) 
Connectors: ¼", RCA, 3.5mm inputs; XLR-F outputs
Construction:  14-gauge steel chassis & outer shell
Finish: Durable powder coat
Size:  (W x H x D)  84 x 127 x 48mm (3.3" x 5.0" x 2")
Weight:  0.70 kg (1.55 lbs) 
Shipping Size: W x H x D: 102 x 76 x 165mm (4" x 3" x 6.5")
Shipping Weight: .87 kg (1.92 lbs)
Power:  +15VDC/400mA adapter Included
Conditions: For use in dry locations only between 5°C and 40°C
Warranty:  Radial 3-year, transferable
Specifications are subject to change without notice.