Replacing Tubes, Service And Preventive Maintenance - Hughes & Kettner TRIAMP Manual

TRIAMP - Manual
5.0 REPLACING TUBES, SERVICE AND
PREVENTIVE MAINTENANCE
TriAmp features factory-equipped 6L6GC, 12AX7A and
E83CC Hughes & Kettner tubes. Hughes & Kettner tubes are
first burned in and then checked for their electrical and
mechanical properties (microphonics), selected and
matched, and then given a final audio and response test
once they have been installed in a completed TriAmp.
One of the most important steps in the testing process is
power tube matching, i.e. selecting and pairing tubes with
identical characteristics.
When should you replace tubes?
The tubes in your TriAmp are of exceptional quality and will
last extremely long. Old tubes begin to show signs of wear
such as increased microphonics and noise, treble loss, weak
power output, muddy sound, etc. Power amp tubes wear out
faster than preamp tubes. If you encounter these problems,
replace the tubes. Not only do old tubes impair the sound,
they are also prone to fail altogether.
NOTE: We recommend you refrain from exchanging tubes
solely for sound experimentation purposes. First of all, this
may end up damaging your amp. Besides, we tested every
conceivable tube option and installed the tube types for the
best possible performance.
Keep the following in mind when you are ready to
replace tubes.
- We recommend only qualified service personnel replace
tubes.
- Before removing the rear panel cover, make certain the
mains cord is unplugged from the wall socket!
- Use only matched pairs of power amp tubes. You may use
5881 (6L6GC-R) tubes instead of the 6L6GC tubes for an
even heavier sound, but, again, only in matched pairs.
- For tonal reasons, we distinguish between 12AX7A and
E83CC preamp tubes. The E83CC is a high-grade version of
the ECC83, a common tube in Western Europe. The E83CC
tube is built by another manufacturer; it features a different
design and subsequently sounds different. In principle, you
may use certain tubes other than those specified on the
chassis in a pinch, but TriAmp sound quality will not be at
its full potential.
- 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.
10
- 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 life of your tubes?
- Use the STANDBY SWITCH! The more often the tubes are
heated up, the shorter their life span will be. The standby
feature switches the anode voltage off and reduces actual
operating time. Avoid mechanical shocks, especially when
the amp is on. Switch the amp off and let the tubes cool
down before transport. A quality flight case is a good
investment and is only slightly more expensive than a
complete set of tubes.
- Proper bias and trim extend the life of your tubes. If you
find the tubes need to replaced too often, consult a qualified
technician.
All other TRIAMP 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.