Hughes & Kettner 20th Anniversary Edition Tube Manual Download Page 8

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EDITION TUBE-MANUAL

- Refrain from DIY repairs! To be on the safe side, you should
also have a qualified technician replace internal fuses.

5.0 TROUBLESHOOTING

1) The EDITION TUBE is not getting any power:

• Check the mains cable to see if it is connected properly.
• The mains fuse may be defective. Replace the fuse with

another identical fuse. If this fuse also trips, consult your
Hughes & Kettner dealer.

2) The EDITION TUBE is connected properly, but no sound is

audible.

• One or several GAIN and MASTER controls may be turned

all the way down. Dial in a higher setting.

• A short circuit in the speaker signal chain may have

tripped an internal fuse, or one of the power tubes is
defective. Replace the speaker cable and have a
qualified service technician replace the fuse/tube
(identical specifications are a must). Please read Section
4.0 on how to replace tubes correctly.

3) The sound is slightly distorted and you cannot get a truly

clean tone.

• The input section is being overdriven. Depending on the

type of pickups in your guitar, this effect is very
pronounced or may not be audible at all. If you don't
want this slight distortion (although many players prefer a
little dirt in their sound), reduce the volume of your guitar
or volume pedal, turn the screws on the frame of your
pickups so the distance between the strings and pickups
is greater, or try a different combination of pickups.

• If the distortion has an annoying gritty edge to it, there

may be some type of fault due to improper use of a sig-
nal circuit, for instance a speaker output connected to
the EDITION TUBE's input. In this case, consult your Hughes
& Kettner dealer.

4) You have connected an FX processor to the SEND jack

and the signal is totally distorted, even when you have
dialed in a clean sound.

• The LINE OUT signal is overloading the input of the FX

processor. Reduce the processor‘s input sensitivity ("INPUT"
or "GAIN").

5) You have connected an FX processor to the SEND jack of

the EDITION TUBE and the signal's volume level is way too
low.

• The FX processor's output level is set incorrectly. Turn it up.

NOTE: We recommend you refrain from exchanging tubes
solely for sound experimentation purposes. Improper use
runs the risk of damaging your amp and will not be
covered under warranty. Besides, we tested every
conceivable tube option and installed the tube types
that deliver 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 chassis, ensure the mains cord is

unplugged from the wall socket! Wait at least 2 minutes
for the amp to power down.

• If you are replacing a power amp tube, ensure the repla-

cement tube bears identical specs.

• Use only matched pairs of power amp tubes.
• If you install a matched pair of tubes bearing precisely

the same specs as the original tubes, the amp does not
have to be re-biased. Conversely, if the specs are not
identical, the amp must be biased. Biasing is a complex
procedure requiring special tools and should only be exe-
cuted by a qualified amp technician.

HOW CAN YOU EXTEND THE LIFE OF YOUR TUBES?

• Never operate the EDITION TUBE without a proper load

(speaker) connected to the output.

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 are essential. If you find the tubes

need to be replaced too often, consult a qualified
technician.

All other EDITION TUBE components do not require
maintenance. Use a slightly dampened cloth for all metal
parts and the exterior surfaces. Avoid exposure to
mechanical shocks, extreme heat, dust and moisture.
Ensure the cooling vents 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 connecting cables
are in a state of good repair! - Ensure plenty of air can
circulate around the amp’s ventilation slots at all times -
your EDITION TUBE’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 EDITION
TUBE 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.