Pass Labs XA100 - Manual (Page 5)

5 XA100 Owner’s Manual
are charged. The “Power” LED should not be on. If the “Power”
LED is on, don’t get excited, just use the front panel stand-by button
to go to stand-by mode, with the “Standby” LED on and the “Power “
LED off.
OK, so the amplifier is sitting there in stand-by mode with just the
single blue LED lit. No speaker connected yet. You can go ahead
and connect the source and speakers. Make sure you are in standby
mode to protect your speakers from transients. The prudent installer
will unplug the XA100’s power cord from the mains while attaching
speaker cables.
To avoid the possibility of short circuits always connect speaker cables
to the speakers prior to connecting to the amplifier. The output
binding posts will accept either bare wire or spades. (Regulatory
agencies in many countries have banned binding posts that will accept
a banana plug, forcing us to abandon this option.) Make sure that your
speaker wires only attach to the outputs of the amplifier, not to each
other and never to the amplifier case.
Some powered subwoofers require an audio signal ground reference
and their makers may suggest that a black speaker terminal is
where this voltage reference might be found. On complementary
designs, which would be typical of all power amps produced by Pass
Laboratories™, this is an incorrect and unsafe assumption. On all
Pass Laboratories™ power amplifiers a reference of 0 volts will be
found only at pin 1 of the XLR input or at the shell of the RCA input.
Reference connections for these devices require special consideration
when used with our product. If you have such a device, and wish to
use it with our product, please contact our Foresthill, California factory
for specific instructions.... you have been warned.
The amplifier may be driven single-end or balanced, your choice.
Single-ended input will always occur through the RCA connector
and balanced input will always occur through the XLR connector. If
driving the amplifier single-ended leave the supplied jumpers in place
between pins 1 & 3 on the input XLR. On the XLR connector pin 1 is
ground, pin two is positive input and pin 3 is inverted (negative) input.
Pin numbers are marked on the XLR. If you re-install the jumper
incorrectly or leave it lying about, the amplifier will not work properly.
You must choose either XLR or RCA inputs it is not advised to try and
run both concurrently.
XLR input connector showing proper
placement of jumper pin for use with
single-ended (RCA) input.