Specifications

3
REAR PANEL FEATURES
L
R
remote main mic
zone
main
limit
threshold
tone
stereo
mono
out
in
+10+10limit
phtm
pwr
15 watts
class 2 wiring
50/60 Hz
~
27V
gnd
IR2
IR3
mute
gnd signal
bypass
off
on
level level
level
trim
pad
L
R
input 4
gnd
hi
lo
L
R
input 3
L
R
input 2
L
R
input 1
level level
BIAMP SYSTEMS
designed and assembled in the USA
www.biamp.com
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)
(1) Power Cord: The external transformer provides 27 Volts AC
to the SPM412e, and is detachable via a 5-pin DIN connector.
Two internal ‘self-resetting’ fuses provide AC over-current fault
protection (not user servicable). These fuses will attempt to re-set
when power is turned off. If these fuses do not re-set, or continue
to trip, it is an indication that the SPM412e requires service.
(2) Remote: When the adjacent switch is released, the ‘IR2’,
‘IR3’, & ‘gnd’ terminals can be used for connection of optional
remote controls (see Remote Control on pg. 6). When the
adjacent switch is depressed, the ‘hi’, ‘lo’ & ‘gnd’ terminals can be
used as a ‘Translator’ input for remote control via third-party
controllers which utilize a carrier-stripped serial bit-stream (see
Translator on pg. 7).
(3) Zone Output: This balanced output carries a mono sum of
the selected Stereo Line Input signal, and the Mic/Line Input signal
(see Modifications on pg. 4). Zone Output provides 6dB of
additional gain when balanced. For unbalanced use, connect
signal to (+) and ground to (
d
), leaving (-) unconnected. When
Mic/Line Input signal is present, stereo input signal may be muted
automatically by up to 40dB (see Mic/Line Input on this page).
(4) Main Output: This balanced stereo output carries the
selected Stereo Line Input signal, and the Mic/Line Input signal
(see Modifications on pg. 4 & 5). Main Output provides 6dB of
additional gain when balanced. For unbalanced use, connect
signal to (+) and ground to (
d
), leaving (-) unconnected. When
Mic/Line Input signal is present, stereo input signal may be muted
automatically by up to 40dB (see Mic/Line Input on this page).
(5) Limit Threshold: This screwdriver adjustable control sets the
threshold level for the internal limiter. When Main Output signal
levels exceed this threshold, the limiter is activated and the
adjacent Limit indicator will light. Limit Threshold range is -4dBu to
+24dBu (balanced) or -10dBu to +18dBu (unbalanced). Use the
limiter to set maximum levels for sound system protection.
(6) Main (Stereo / Mono): When depressed, this switch
combines the stereo left & right Main Output signals into a mono
sum, which is then sent to both left & right Main Outputs. When
Main Output is set for mono operation, the front panel Balance
control still affects the relative level of the left & right Main Outputs.
(7) Tone (Bypass): When depressed, this switch bypasses the
front panel Bass & Treble controls. Tone Bypass defeats any tone
adjustments made to the Main Output signals.
(8) Inputs 1~4: These RCA connectors provide the unbalanced
Stereo Line Inputs for line-level signals (-10dBu or +4dBu). Use
these inputs to accept signals from cassette, CD, VCR, tuner,
satellite, cable, computer, etc. Inputs 1~4 each have a screwdriver
adjustable control for setting level of the corresponding Stereo Line
Input signal. Use these controls to compensate for different input
signal levels. For best performance, reduce level only on inputs
which are higher than the others. These controls are factory set
fully clockwise for +10dB of gain. This is appropriate for most
inputs such as CD, cassette, tuner, etc. (-10dBu nominal levels).
(9) Mic / Line Input: This balanced input will accept either low-
impedance microphone or line-level input signals. For unbalanced
use, connect signal to (+) and ground to both (
d
) & (-). Three
additional terminals are provided for ‘page-over’ muting of the
Stereo Line Input signals. By wiring ‘signal present’ to ‘mute’,
automatic muting of the currently selected Stereo Line Input will
occur whenever signal is present at the Mic/Line Input. Manual
muting of the currently selected Stereo Line Input is achieved by
wiring a switch or contact-closure between ‘mute’ and the adjacent
‘gnd’ terminal. From the factory, ‘page-over’ muting is set for
-40dB, and is assigned to both the Main Output and the Zone
Output (see Mute Assign & Mute Adjust on pg. 4).
(10) Pad: When depressed, this switch reduces the Mic/Line
Input signal level by 30dB (see Mic/Line Input above). Use this
switch when Mic/Line Input signal levels exceed the normal
operating range of the Trim control, or whenever a line-level input
signal is connected.
(11) Trim: This screwdriver adjustable control sets gain at the
Mic/Line Input (see Mic/Line Input above). Use this control to
compensate for different input signal levels. For best performance,
adjust Trim so the adjacent +10 indicator flashes only on
occasional peaks in signal level.
(12) Phantom Power: When depressed, this switch provides +24
Volt Phantom Power to the Mic/Line Input (see Mic/Line Input
above). Phantom Power is for powering condenser microphones.
CAUTION: Never turn Phantom Power on when line-level signal
devices are connected to the Mic/Line Input. Always turn power
off and Mic Level down before switching Phantom Power or
making connections to the Mic/Line Input.