Hughes & Kettner MK II Musical Instrument Amplifier User Manual


 
TriAmp
®
MK II 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.
TriAmp
®
MK II is connected properly,
but no sound is audible:
• The amp is set to STANDBY.
• One or several GAIN and MASTER controls are
turned all the way down. Dial in a higher setting.
• The anode fuse is blown. Before you replace the
fuse, examine whether the power amp tubes
are defective.
• The fuse for the tube heater blew (the tubes
don’t glow). Make absolutely certain to check
the rating when replacing this fuse. It is a super-
slo blo TT 15 A fuse. This type of fuse is relatively
uncommon and may be hard to find in your
area. That’s why your TriAmp
®
MK II shipped with
a replacement fuse. Be sure to have a service
technician replace the fuse.
Fuse keeps on blowing:
• After replacing the fuse, with standby off,
turn on the power. Watch the power tubes,
turn standby on. Look for tube “flash” before
fuse blows, indicating excess oxygen within the
tube. This will show which power tube needs to
be replaced.
The FX LOOP is on when
it shouldn’t be:
• The FX LOOP is deactivated when the front
panel button, the Stageboard button and the
MIDI module switching function are off. If any of
these three switches is on, the circuit is active.
The sound is thin and muddy when
the effects processor is active:
• The effect device routes back a dry signal that is
added to the original dry signal in the parallel
effects loop. Depending on the type of em-
ployed effect device, the phase position of the
dry return signal can lead to cancellations when
the return and original signals are mixed. To fix
this problem, switch the effects loop to SERIAL
or turn the dry signal all the way down on the
effect device.
When in use with a loud PA,
the RED BOX
®
DI OUT circuit is causing
feedback even though the amp is set
to a low MASTER volume:
• Speakers connected to a tube amp may have
microphonic properties. Turn TriAmp
®
MK II’s
Master VOLUME up and the circuit will stop
feeding back. In extreme cases of microphonic
speakers, you would either turn the PA down
or mic the cabinet.
Your amp is producing ringing noises
or tends to feedback:
• One or several tubes are microphonic.
Replace the appropriate tube with another
of the same type.
After just a few hours of operation,
your amp is displaying the typical
characteristics of old tubes (increased
microphonics and noise, treble loss,
weak power output, muddy sound).
• You have installed the wrong tubes or the bias is
not adjusted properly. Take the amp to a profes-
sional amp technician to correct the problem.
TRIAMP MK II - MANUAL
14
14
6.0 TROUBLESHOOTING