Q4 Audio DPI 10 User Manual - page 10
DPI SERIES USER MANUAL
9
Each channel is controlled from the front panel by a level con-
trol potentiometer and 4 status LED’s. The status LED’s indicate
the following operational states of the amplifier:
READY/PROTECT:
two-coloured LED indicates whether or
not the channel is ready to operate. Lights up green when the
amplifier is working normally, and turns red whenever there is a
malfunction, e.g. DC voltage at the output, output stage defect, or
heatsink temperature exceeding 90°C. After turning the amplifier
on, this LED will remain red for about 2 seconds until the internal
supply voltages have set to their normal values.
SIGNAL:
indicates signal presence at the channel’s output.
Threshold level is +0 dBV.
VOLT CLIP / LIMIT:
lights when the amplifier has reached
the minimum switching frequency. This is equivalent to clipping
in a normal power amplifier. In case the internal clip limiter is
activated, the gain will be automatically reduced to prevent the
occurrence of gross nonlinearity conditions inside the amplifier.
The clip limiter keeps signal distortion under 5% and thus
guarantees a clean sound and effective speaker protection.
TCL (Temerature Controlled Limiting):
indicates signal
limiting as a result of heat sink over temperature (above 85°C).
This helps to prevent the triggering of the internal thermal shut-off
circuit, which would step in at 90°C heat sink temperature as a
final safeguarding measure.
The temp limit only becomes active when the regular cool-
ing mechanism fails to work properly, e.g. by a dirty air filter,
obstructed air-flow...
A lit TCL LED should always be taken as a sign to check the
air filter and to assure sufficient cooling air supply.
Further 3 leds give operational information of the unit:
BRIDGE:
Indicates the amplifier is configured for bridge mode
operation. Use CH1 level control as indicated.
SUPPLY OVL:
Indicates a power supply overload. If this LED
is lit, gain of both channels is decreased simultaneously to avoid
overheating of the unit’s power transformer.
REMOTE:
Both the ‘ACTIVE’ LED as the CALL button are
functions which require an optional remote module to be inserted
at the back of the unit. Further explanation of the functions will
accompany the remote module. This function is not available
with the PIM-SIM standard input module.
6. Operation
READY / PROTECT
SIGNAL
BRIDGE
VOLT CLIP / LIMIT
CH 2
-dB
CH 1
-dB
TEMP LIMIT
SUPPLY OVL
0
oo
2
4
6
8
10
12
14
18
24
0
oo
2
4
6
8
10
12
14
18
24