Emotiva UPA-2 - Manual (Page 19)

Page 18
• Check that the speaker wires have been connected correctly: Make sure that the positive of each
speaker connects to a positive output of the amplifi er, and the negative of each speaker connects
to a negative output. If one speaker is wired incorrectly, than it will be “out of phase” with the others,
resulting in poor bass performance. DOUBLE CHECK ALL THE SPEAKER CONNECTIONS!!
Turn-on and turn-off thumps
• Plug the amplifi er into an un-switched AC outlet, and use the 3.5mm Trigger Input connection
with a trigger between 5-12VDC from the source unit or preamplifi er (such as the Emotiva LMC-1
Preamplifi er/Processor). This should allow the amplifi er to turn on and off silently.
• If your powered subwoofer is the cause of the “thump” sound (not the other speakers connected to
UPA-2), plug it into a different 115VAC outlet than the UPA-2 amplifi er so there is no power
confl ict.
• Install a line conditioning device.
“Hum” Noises in the Speakers
This problem is more than likely caused by a “ground loop” in your system, rather than a fault in the
XPA-1. Follow these steps to isolate the main cause of the hum; there may even be more than one.
• Remember to turn off all components in your system, including the amplifi er, before disconnecting or
connecting any cables during troubleshooting.
• Try to have all of your equipment on the same electrical outlet or circuit. Group all the low power
components (preamp, CD player, DVD etc.) on a single outlet or power strip. This is provided that
the overall current draw from your equipment does not exceed the rating of the outlet or breaker.
• Disconnect all cables which come from outside the room, and check if the hum goes away. This
includes such connections as cable TV, satellite TV, or roof top antennas. Make sure that they are
disconnected where they fi rst enter the room, so they are making no connection to the preamplifi er
or the TV, or any other component. If the hum is caused by the cable TV line, then you will need
a “ground loop isolator.” This is an inexpensive device fi tted in line with the coaxial cable feed.
Contact your cable company or your Emotiva Dealer for assistance.
• Disconnect all connections from the preamplifi er to your TV, VCR or DVD.
• As a test, disconnect any other component which has a grounded power cord.
NOTE: Never remove the ground pin from any power cords (if present). This is very
dangerous.
• If the hum persists, disconnect all the source components one at a time from the back of the
preamplifi er, until you identify the problem.
• Try moving the speaker cables away from any power cords. Try just one speaker, connecting it to
each amplifi er channel and see if one channel is bad.
• Check that the interconnect cables to the amplifi er do not have any broken connections. The best
way to do this is to substitute a known good connection for the suspect connection. If you reverse
the cables and the problem goes away, the cable may be damaged or broken. This is possible even
if you can’t physically see the break as the strain for pulling on audio cables can sometimes break
the wire internally.
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