Hughes & Kettner Warp-T Manual page 12

WARP T - MANUAL
What should you keep in mind when
you're replacing tubes?
The golden rule: Replacing tubes is a job best
left to qualified professionals. Accordingly, these
guidelines are addressed to qualified technicians
who earn their living with a screwdriver:
Pull the mains plug of the WARP T™ and allow for
a discharge time of at least two minutes before
removing the sheet metal panel on the rear of the
amp. Once the panel is off, you can cautiously
ease the tubes out of their sockets. A single power
tube may only be replaced if the replacement
tube precisely matches the original, in other
words, if it has exactly the same characteristics.
If you're replacing power tubes, use matched sets
only. If you're installing a new set of power tubes
whose characteristics are identical to those of the
old set, it is not absolutely necessary to re-bias the
amp. On the other hand, if you install a new set
with different characteristics, be sure to re-bias the
amp. Again, biasing an amp is not a DIY task. It
requires experience and an extensive working
knowledge of measuring techniques, which is why
this job should be carried out only by qualified
technicians with tube amp tuning experience.
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How do you extend the service life of
the WARP T™'s tubes?
• Never operate the WARP T™ without connecting
a load (loudspeaker)! Always use high-quality,
heavy-duty speaker cables that won't crimp or
snap...
• Use the STANDBY switch! Warming tubes up
unnecessarily wears them out that much
quicker. Make a habit of cutting 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 it, allowing plenty of
time for the tubes to cool off completely.
• Ensure plenty of air can circulate around the
amp's ventilation slots at all times –
your WARP T™'s life depends on it.
• Definitely avoid exposure to 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 impe-
dance (ohm) rating lower than the WARP T™ is
designed to handle.
• Never connect devices with high output signal
levels (e.g. power amps) to the
WARP T™'s input.
• Ensure 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 performing DIY repairs! To be on
the safe side, you should also have a qualified
technician replace internal fuses.