Hughes & Kettner Bass Base 400 - Manual (Page 8)

BASSBASE 400 - MANUAL
4.0 SERVICE AND PREVENTIVE
MAINTENANCE
The BASSBASE 400 will not require service of any type for
many years. Tube fatigue is normal after several thousand
operating hours and becomes apparent through treble loss or
increased microphonics (audible as a ringing noise
reproduced by the tweeter).
Use a soft, slightly damp cloth to clean the BASSBASE 400’s
metal parts. Use a brush to clean the flock covering (combo
version).
Avoid exposure to mechanical shocks, extreme heat, dust
and moisture.
5.0 POSSIBLE ERROR SOURCES/
TROUBLE-SHOOTING
E1)
The BASSBASE is not getting any power:
- Check the mains cable to see if it is connected properly.
- The mains fuse is defective. Replace the fuse with another
identical fuse. If this fuse also blows, consult your Hughes &
Kettner dealer.
E2)
The BASSBASE is connected properly, but no sound is
audible.
- The MUTE function is activated. Press the MUTE button!
- One or several GAIN and MASTER controls are turned all
the way down. Dial in a higher setting.
- The FX-MIX control is turned all the way to WET but you
have not connected a processor to the FX loop. Turn the FX-
MIX knob to DRY.
- One of the circuit breakers has tripped. Locate and
eliminate the defect (e.g. inadequate ventilation, defective
speaker cable)
- One of the internal fuses is blown (e.g. caused by a
permanent short in the speaker output jack). Locate and
eliminate the defect and have the fuse changed by a
qualified service technician (make sure the replacement fuse
bears the proper rating).
E3)
Using a footswitch, you are unable to turn off the
VARIMETRIC EQ or the FX LOOP:
- The EQ or FX LOOP front panel selector switches were
inadvertently left in the ON position. Press the appropriate
selector switch to disengage the front panel control.
E4)
The sound is thin and muddy when the FX processor is
active.
-
The signal processor is causing phase shifting that is being
added to the original signal in the parallel loop. Turn the
FX-MIX control all the way to the right (WET) to avoid phase
cancellations.
E5)
The red CLIP LED keeps illuminating.
- The BASSBASE 400’s input is overloaded. Press the - 10 dB
button or turn your instrument’s volume pot down.
- The BASSBASE 400 preamp is overloaded. Reduce the
GAIN.
- The BASSBASE 400 FX LOOP is overloaded. Briefly
disconnect the FX processor from the loop. If the CLIP LED
no longer illuminates, you must reduce the processor’s
output level.
E6)
When accessed, the DI OUT jack causes annoying hum.
- The connected device’s input circuit is unbalanced and an
electrical or magnetic field is causing interference. Use a
balanced input or situate the cables to reduce interference to
a minimum.
- The grounding of the connected devices are causing a
ground loop. Do not sever the ground of the connected
devices under any circumstances! Activate the GROUND
LIFT SWITCH. If this doesn’t eliminate the noise, you must
ensure the connection is galvanically separated by routing
the signal through a DI box.
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