6/17/2017
XKITZ XAMP-M2
6
Input Signal Configuration – Balanced or Unbalanced (Optional)
There are two basic systems used to connect the audio signal on consumer and pro audio equipment;
unbalanced lines and balanced lines. Unbalanced lines use one wire for signal and the other for ground.
Balanced lines, on the other hand, have two signal wires and a shield ground wire.
Unbalanced lines are most common in consumer grade audio, and are generally much more susceptible to
audio noise like 50/60Hz hum. Unbalanced lines will also pick up any electro-magnetic noise in the nearby
environment (such as computers, cell phones, microwaves, etc.) and adds it to your audio signal, making it
audible in your speakers. Unbalanced lines can also lead to ground loops, which are the major source of
50/60Hz hum in your sound system. Ground loops arise whenever there is more than one path from any piece
of audio equipment to earth ground. Your equipment will always be grounded through your AC line. Adding
another path to ground through your unbalanced audio cable adds a second path to ground, and this can
cause audible 50/60Hz hum.
Balanced lines are more common in high end consumer and professional audio systems and are much less
susceptible to noise. Balanced lines allow you to run very long audio cables without allowing electro-magnetic
noise to couple into your signal. They’re also not susceptible to 50/60Hz hum; there is no connection to ground
in the audio signal cable, so they can’t create ground loops in your sound system.
For unbalanced signal input, you’ll install the RCA jack in location J2, and leave the J1 location empty.
For balanced signal input, you’ll install the 3.5mm TRS jack in location J1, and leave the J2 location empty.
Figure 2.
Balanced Mode signal Input TRS Jack Wiring
Heat Sinking
The XAMP-M2 includes a heat sink to remove heat from the LM4766 amplifier chip. This heat sink is sufficient
for lower power applications. For applications that are expected to run at high power for long periods of time,
you may want to attach an additional heat sink to augment the existing one.
The stock heat sink is conveniently mounted on one edge of the board, allowing easy attachment of an
additional heat sink, or to the interior wall of a metal chassis.