PSW111 hums

spudknuckle

Hi,
I just bought a PSW111 and a set of TL250s, and hooked it up. When the power is on, there is a hum that increases with the volume. The hum is faint with no signal, but when there is a signal the hum increases quite significantly. I had an Energy sub hooked up to the same system, and that worked fine.

Anyone have any advice?

Thanks in advance...

[Deleted User]

Hello spud,
Welcome to Polk's forum. Does the sub hum if there isn't anything connected to it?
Regards, Ken

spudknuckle

Hi Ken, and thanks...
No, it doesn't hum if there's nothing connected. And then, it's a faint hum until there is a signal detected. At that point, the hum becomes much more pronounced. Like I said in my original post, it works fine with the Energy sub, but I get the hum from the Polk sub. Thanks and regards,
Mitch

specd_out

almost sound like a ground is bad on the sub or the cable might not fit snug enough on the polk

[Deleted User]

Hi spud,
Let's try a test. Remove your DVD/CD player from your receiver and bring it to where it can be connected directly to the sub with the sub's volume all the way off. Take two RCA cables and connect the right and left outputs of the DVD/CD player to the corresponding right and left inputs on the PSW111. Then start playing a CD and turn the volume up on the sub. There should be bass information but no humming.
Regards, Ken

spudknuckle

Ok Ken, finally got back to it...

I hooked a player up directly to the sub, using RCA cables. i put in a cd, and got virtually no hum. i hooked up the LFE input again, turned on my receiver, and... hum. bad connection on the LFE cable?

Thanks again, and best regards,
Mitch

[Deleted User]

Good, I think the sub is working correctly. Can you describe the kind of cable you are using between the receiver and the sub? Is it a shielded coaxial cable or is it made of two conductor speaker wire? Does the cable run through your walls?

spudknuckle

it's a 2-conductor wire that's run through the wall. last night i experimented by temporarily grounding the shield of the RCA plug, and the hum went away. and for whatever it's worth, my receiver has a 2-prong power plug

[Deleted User]

The problem is with the two-conductor wire used as a line level connection. All you need to do is cut off the RCA plugs on both ends and connect the wire as a speaker level connection. Just connect to the right channel positive/negative front speaker connection (leave the original right speaker's wire in the same place it already is). Then make the other end of the speaker wire connect to the right channel speaker input connection on the sub.
Set the front speakers to "large" and switch the "sub-out" function "off" on the receiver's setup menu. It should sound fine and no humming.

spudknuckle

Ok, Ken, that looks like it did the trick! thanks for your help, and happy holidays!

Regards,
Mitch

[Deleted User]

Good, I'm glad things are sounding better, Mitch.
Take care, Ken