User guide
10
Operation
Front Panel Controls
The SP20 has two microprocessor-driven rotary controls and three buttons
(Power, Mute and Speaker Off).
Left Rotary control (Input Select): Select input by rotating the control to
the left or right. The screen displays the current input by factory-set and
user-denable name at the top right.
Right Rotary control (Volume): Adjust volume (output level) up or down for
both L and R channels. Volume control is also selectable via Vol UP and Vol
DN buttons on the remote control. Volume adjustment is indicated in the
display window by numeric digits on 0–103 scale.
Do not turn volume up beyond normal listening levels when ‘mute’ is
engaged to avoid unexpected or possibly damaging sound levels. Reduce
volume level whenever changing input sources, even when muted.
Power On/Off: Supplies power from A.C. wall outlet to preamp; indicated
by active display window. The SP20 requires approximately 30 seconds to
warm up; this time is required to stabilize the power supply. See ‘Power-Up
Procedure’ on the adjacent page for details.
Mute: When activated, electrically mutes all output of the preamplier;
indicated by ‘Mute’ in display window. This control should be activated
before switching inputs, changing connections or shutting down your audio
system to help protect your amplier and speakers from unexpected signal
pulses. When deactivated, ‘Mute’ disappears from the display window
allowing normal operation.
The SP20 also has automatic muting to help protect system components
in the event of low line voltage. When sensing low line voltage, the preamp
displays ‘Low Line’ and automatically goes into ‘Mute’. This condition will
persist until the line voltage returns to a safe operating level; please note the
unit will remain in ‘Mute’ even after ‘Low Line’ no longer appears.
Note that automatic muting is only designed to protect against power line
interruptions or severe voltage drop. It will not mute in the event of subsonic
transmissions from a faulty input source, amplier failure or speaker
malfunction.
Spkr Off: Toggles between the main outputs on the back of the unit and the
headphone jack mounted adjacent to the Speaker Off button.