7B
SST
2
POWER AMPLIFIER
LED Indicator
The
7B
SST
2
has a single LED indicator to monitor the following conditions:
U
nlit
•
indicates the amplifier has no power.
R
ed
•
indicates the amplifier is muted (power-up)
G
Reen
•
indicates the amplifier operation is normal.
F
lashinG
R
ed
•
indicates the amplifier clipping.
O
RanGe
•
indicates channel thermal shutdown.
Power-Up Sequence
After pushing the front panel power switch, the LED will turn from unlit to red (mute). When the power supply has
stabilized the amplifier will come out of mute and the LED will change to green (normal operation).
Unlit LED (No power)
The
7B
SST
2
LED when unlit indicates no A/C mains power is present and the amplifier probably needs only to
powered on. Ensure that the rear panel circuit breaker is switched ON.
Clipping (flashing red)
Clipping occurs when the channel output level no longer can follow the level increase at the input (Over driven
input condition). When the
7B
SST
2
is driven into clipping the LED will change from green to red then back to
green when the level is reduced ( Flashing Red ). Momentary clipping can be tolerated, however it indicates that
maximum un-distorted power has been surpassed and potential speaker damage may result if overload condi-
tions persist. Any amplifier that is constantly operated into clipping indicates a more powerful amplifier is needed
for that application.
Thermal Shutdown (orange)
The
7B
SST
2
has thermal shutdown circuitry to prevent damage due to overheating. Should thermal shutdown
occur, the amplifier will mute, and the LED will turn orange indicating this condition. When the amplifier has
cooled to a safe operating condition the
7B
SST
2
will return to normal operation. Persistent Thermal shutdown
indicates steps need to be taken to increase airflow across the heat sink.
Also see installation section on ventilation.
N.B.
In some markets the LED indicators, which are normally red/green, may be red/blue instead. When red/blue LEDs
are supplied green is replaced with blue and orange is replaced with magenta in the above descriptions.
REAR PANEL
INPUT SELECT SWITCH
Gives the user the option of switching between either balanced input or single ended input.
BALANCED INPUT CONNECTOR
This input connector accepts standard ‘XLR’ or 1/4” Tip-Ring-Sleeve phone plugs.
Use quality, 100% shielded cables
with
gold plated
connectors.
SINGLE ENDED INPUT
( Un-balanced input )
This input connector
accepts standard ‘RCA’ or ‘Phono’ connectors.
Use quality, 100% shielded cables with
gold plated
connectors.
Balanced input Vs Single ended input:
The balanced input requires a balanced pre-amp source. Balanced systems provide noise rejection from external
electrical interference, so cable length can be very long ( 50m or longer ). The single ended or unbalanced input is
provided for pre-amps without balanced output. Single-ended cables should be kept to 20’ (7m) or less. In general
never use longer cables than necessary, never coil excess cable length, and keep signal wires away from AC power
or speaker cables.
