DANGER: RISK OF ELECTRIC SHOCK, DO NOT OPEN
ATTENTION: RISQUE DE CHOC ELECTRIQUE, NE PAS OU-
VIRIR
ACHTUNG: STROMSHLAG GEFÄHRDUNG, NICHT
AUFMACHEN
CAUTION: To reduce the risk of electric shock, do not remove
cover or open rear panel. No user serviceable parts inside: refer
handling to qualified personnel. To reduce the risk of fire or elec-
tric shock, do not expose this product to rain or moisture.
Uninsulated dangerous voltage may be present inside the enclo-
sure – voltage that may be sufficient to constitute a risk of shock.
Changing your amplifier tubes is safe, after allowing them to cool.
There is no set timeline for changing tubes. If you play every day,
a good rule of thumb is to replace your power tubes once a year
and your preamp tubes every other year. However, it is entirely
possible for tubes, particularly preamp tubes, to last decades.
Here are some signs that you need to change your tubes:
Excessive noise like squealing, humming, or hiss
Little or no high end or muddy low end or loss of clarity
Mysterious fluctuations in the amp’s overall volume or no sound
Most Jet City Amplification tube amps operate on a Fixed-bias,
which allows you to change both preamp and power tubes of the
same type without needing a bias adjustment. Fine adjustment to
the bias is possible, but only by a qualified service technician.
