Tube Replacement - SWR Headlite Owner's Manual

P. PREAMP OUTPUT*—This post-master volume output is
suitable for connection to the input of an auxiliary power
amp, such as the SWR amplite™.
Q. FOOTSWITCH—Plug the (optional) footswitch in here
using the supplied cable to enable remote operation of
Mute, FX Bypass and Tuner features.
• MUTE—Press to switch the Mute circuit ON-OFF.
• FX BYPASS—Press to switch the effects loop circuit
ON-OFF.
• TUNER and MUTE—Press and hold MUTE for one second
to activate the built-in Tuner. Strike a single string and
the nearest note will appear in the footswitch display. The
red LED (left) indicates the note is flat, the blue LED (right)
indicates the note is sharp, and the green (center) LED
indicates the note is in tune.
NOTE: The headlite footswitch contains an integrated
instrument tuner which only operates when plugged into
the footswitch jack. It is not a stand-alone tuner and is not
intended for connection to a bass or audio signal.
* NOTE: The rear panel 1/4" jacks {P, R, V and W} are balanced TRS (Tip/Ring/Sleeve) outputs:
While standard shielded TS (Tip/Sleeve) "mono" guitar cables can certainly be used, the use of "stereo" TRS cables may improve signal-to-noise
ratio and/or reduce hum, especially when longer connections are required.
A 12AX7 dual triode vacuum tube (valve) is
at the core of your headlite pre-amplifier.
Typically a 12AX7 tube will last several years, but
through heavy use and frequent transportation
vibration, it is possible to have a tube last less
than a year.
8 8
rear panel rear panel
R. DI*— Line level output suitable for connection to studio
and "front-of-house" (live) mixing consoles. These true
electronically balanced XLR and 1/4" TRS jacks are line level
outputs in order to maximize the signal to noise ratio. To
avoid clipping (especially with the XLR output) make sure
to set the console input level to "LINE LEVEL" or reduce the
output level using the Level {U} control.
S. GROUND / LIFT—Select LIFT to disconnect the ground
connection (pin-1) from the DI XLR jack {R} to reduce noise
caused by ground loops. Normally leave this switch in the
GROUND (out) position.
T. PRE / POST—Select PRE to supply the DI outputs {R} with
a signal taken immediately after the first tube stage for
the best DI (direct box) sound. Select POST to include all
preamp circuits (tone, compression and effects).
U. LEVEL—Adjusts the output level of the DI output jacks {R}
to accommodate a variety of sound equipment connections
and input sensitivities.
V. EFFECTS LOOP*—Connect Send to your effects input and
Return to the effects output. NOTE: Any effects device with
a "WET/DRY" control should be set to the fully WET position
to prevent phasing problems. Effects "INPUT LEVEL" should
be set as close to 0dB as possible.
The Send output includes onboard tone shaping. Send
level is primarily controlled by Gain {F}. The Return "WET"
effects signal is blended with the "DRY" preamp signal in
the amount selected by the Effects Blend {J} knob.
W. DIRECT OUTPUT*—Line output that can be used to
connect a standard instrument tuner or as an auxiliary
line out. Use the Mute {C} switch to disable speaker and DI
output while tuning.
Tip=positive (+)
Ring=negative (–)
Sleeve=ground.

tube replacement

tube replacement
When to replace the preamp tube: Sometimes tubes become
noisy or "microphonic" as they wear out (sounds like glass chimes
during certain notes), but other times tubes fail without warning.
If your amplifier stops working and other possible causes have
been eliminated (breakers, cords, etc.), have an authorized service
center inspect your amplifier for tube failure.
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