Note: when the mute switch is engaged, a signal will NOT be sent to the mixing console through the
XLR output. Again, a very handy feature when onstage and the unpleasant sound of tuning is not
something you wish the audience to hear amplified through the sound system.
Selectable Limiter, In and Out
In order to prevent hard clipping of the power amplifier, a selectable limiter is provided.
Master Volume Control
The master volume control allows you to adjust the overall signal level of the amplifier.
Rear Panel
XLR Balanced Line Out Jack
Located at the rear, this jack is used to connect directly to a mixing console, live or in the studio.
There are two lineout modes, Tube DI and Line, which are selectable via the mode switch on the
front panel. This allows you to select either a pre EQ (Tube DI) or post EQ/EFX (Line) signal.
Effects Send ¼-inch Jack
The signal from this balanced jack is post-EQ. The signal from this output is provided to allow
external Effects units to be used with this amplifier. This output can also used as an additional line
out to another power amplifier.
Effects return ¼-inch Jack
This balanced jack is used to return the audio signal that's been processed by external effects units
back into the XS400. Once connected, adjust the amount of wet (processed) signal returning to
the XS400 with the Effects control located on the front panel. This input can also be used for other
external signals that you might want to mix in such as pre-recorded audio.
Amp input ¼-inch Jack
Connect an external source directly to the XS400's power amplifier, bypassing the tube-preamp
completely. The Master control will then control the overall output level.
Output Jacks ¼-inch
These jacks are used to connect extension speaker cabinets, keep in mind that the Minimum
impedance is 4 ohms.
NOTE: all output connectors are connected in parallel.
Output Speakon™ Jack
Some high power Bass speaker extension cabinets use Speakon™ connectors. A Speakon™ out-
put jack has also been provided to connect to similarly configured extension speaker enclosures.
Tweeter Auto-Mute
Engage the switch when you want to enable the tweeter
while in the overdrive mode. In bypass mode, normal oper-
ation of the tweeter is defeated by the Auto-Mute circuitry.
Tip: If you wish to disable the tweeter in the Normal (clean)
mode, simply use the Drive mode, turn the Drive Mix control
to the dry setting (and make sure that the "Tweeter Auto-
Mute" (on the rear of the unit) is set in the OUT position.
Preamp Tube Replacement
Use only Yorkville Sound part number “12AX7SORTED”
when replacing preamplifier tubes as they have been
specifically selected for this product.
Please refer to the
Service Manual for more information.
SPEAKER OUTPUTS
Min 4 ohms
Line
Out
Amp
In
EFX
Send
EFX
Rtn
Tweeter
Auto-Mute
SP
EA
KO
N
™
P
in
Co
nf
ig
ur
at
io
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DESIGNED & MANUFACTURED BY YORKVILLE SOUND • TORONTO, CANADA
1+
1–
active
disabled
L ne
Out
Tweeter
Auto-Mute
active
disabled
L ne
Out
Tweeter
Auto-Mute
active
disabled
