Hughes & Kettner MK II Musical Instrument Amplifier User Manual


 
If, on the other hand, you install a new set with
characteristics that deviate from the old set,
you definitely should re-bias the amp.
Again, biasing an amp is not a DIY task. It takes
experience and a extensive working knowledge in
measuring techniques, which is why this job should
be carried out exclusively by qualified technicians
with tube amp tuning experience.
• A hum adjustment must be made every time
tubes are replaced. Activate AMP 2, CHANNEL B
and AMP 3, CHANNEL B and set the lowest noise
levels via the trimmer.
• Select input tubes with minimal microphonic
properties and lowest noise levels by conducting
a simple listening test.
• As a rule, the amp will not absolutely need to be
re-biased with each new set of tubes, assuming
you use a matched set. Biasing is complex
procedure requiring special tools and should
only be done by a qualified amp specialist.
How can you extend the service life
of tubes?
Never operate the TriAmp
®
MK II without connec-
ting a load (loudspeaker)! With this in mind,
you should always use high-quality, heavy-duty
speaker cables that won’t crimp or snap.
Use the STAND BY switch! Warming tubes up
unnecessarily wears them out that much quicker.
Make a habit of shutting down the anode voltage
via the Standby function and you’ll enjoy many
more hours of operation.
Avoid exposing the amp to vibrations, especially
when it’s powered up. Switch the amp off a good
while before moving the amp so that the tubes
can cool off completely first.
Proper biasing and trimming extend service life.
Whenever you feel that tube wear is on the rise,
be sure to have a technician check the amp’s
bias and trim settings.
All other TriAmp
®
MK II components do not require
maintenance. Use a soft slightly damp cloth for
all exterior parts. Avoid exposure to mechanical
shocks, extreme heat, dust and moisture. Ensure
the cooling vents at the top of the housing are
not obstructed during operation.
Here are a few more basic rules that will extend
the service life of your amp enormously if you
follow them:
• Make sure all peripheral devices and connec-
ting cables are in a state of good repair! –
Ensure plenty of air can circulate around
the amp’s ventilation slots at all times – your
TriAmp
®
MK II’s life depends on it.
• Definitely avoid exposure to mechanical shocks
and extreme heat, dust and particularly moisture.
• Be very careful about the kind of peripheral
devices you connect to your amp and always
check out their specs before you plug them in.
Never connect speaker cabinets with an
impedance (ohm) rating lower than the
TriAmp
®
MK II is designed to handle. Under no
circumstances should you connect devices with
high output signal levels (e.g. power amps) to
your amp’s input.
• Be sure the AC power source delivers the current
that your amp is designed to handle before you
plug it in. When in doubt about the local rating,
ask the venue’s sound technician or a stage hand.
• Refrain from DIY repairs! To be on the safe side,
you should also have a qualified technician
replace internal fuses.
TRIAMP MK II - MANUAL
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