Owner's Manual

11
Front Panel Controls
On-Off Button
Push once to turn on the JC 3 Jr. The audio output is delayed for a few seconds as its
circuits stabilize and the DC servos settle down. When the JC 3 Jr. is turned on the faint blue
glow around the On-Off button will become brighter. Push again to turn off the JC 3 Jr.
Note: The On-Off button is disabled when the Turn On Options switch (on the rear
panel) is set to 12
V.
Mono Button
Press the Mono button one time to parallel the left and right stereo channels to mono. Press
it a second time to return to stereo. The Mono button glows blue when stereo is selected and
changes to amber when mono is selected. Older mono records and stereo records pressed
with high levels of rumble will sound cleaner when you select mono on the JC 3 Jr.
Design Overview
John Curl’s phono preamp design are legendary. His skills for amplifying extremely low level
signals gives you, the listener, the best possible opportunity to experience the full emotional
content of vinyl. In the JC 3 Jr. the physical implementation of the circuits closely follows the
actual circuit topology and the layout is as compact as possible to minimize pickup of
external noise.
The sensitive phono circuitry is isolated by a thick aluminum partition. This separates critical
audio signals from the non-audio circuits and wiring.
The JC 3 Jr. power supply uses a high capacity 1 ampere toroid power transformer. The
transformer is encased (“potted”) in epoxy within a steel enclosure to further reduce any
vibration or noise contamination.
The JC 3 Jr. employs a common mode inductor to reduce noise from the AC power source
from coming into the power supply board. The resulting extremely low noise levels enable
musical nuances to emerge from an utterly silent background.