Emotiva UPA-2 manual Turn-onand turn-offthumps, “Hum” Noises in the Speakers, dangerous

Models: UPA-2

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Turn-on and turn-off thumps

Check that the speaker wires have been connected correctly: Make sure that the positive of each speaker connects to a positive output of the amplifier, 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 amplifier 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 preamplifier (such as the Emotiva LMC-1 Preamplifier/Processor). This should allow the amplifier 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 amplifier so there is no power surge conflict.

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 amplifier, 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 first enter the room, so they are making no connection to the preamplifier 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 fitted in line with the coaxial cable feed. Contact your cable company or your Emotiva Dealer for assistance.

Disconnect all connections from the preamplifier 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 preamplifier, until you identify the problem.

Try moving the speaker cables away from any power cords. Try just one speaker, connecting it to each amplifier channel and see if one channel is bad.

Check that the interconnect cables to the amplifier 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.

“Hum” Noises in the Speakers Page 18

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Emotiva UPA-2 manual Turn-onand turn-offthumps, “Hum” Noises in the Speakers, dangerous