[grub]

Hey all,
I've recently picked up a QSC RMX 2450 to power my passive HT sub.  I'm having trouble adapting my sub-out (RCA) on my reciever to fit into the TRS jacks on the sub amp.  I went to ratshack and picked up a slew of adaptors, but I can't seem to get much but noise from the sub though.  

When I use the female RCA to mono TRS adaptor I get sound, but I have a VERY loud hum on top of it.  The hum changes volume with the controls, and I think it might be a ground loop.  The trouble is that I get the exact same hum when I try other AC outlets and unplug other components in my HT.  I tried to troubleshoot it by plugging in my minidisk player mic into the sub amp, and when I do I get a signal and a dead-quite backround (except for the amp fan).  

I also used a femal RCA to stereo TRS adaptor, hoping that would take care of the problem, but then I had no signal at all...nothing.  I even went  so far as to cut one end of a spare RCA cable off and hook it up with the barrier strip inputs....same hum.

Does anyone know what's causing this hum, and what I can do to get rid of it?  I just ordered a proper cable with a TRS jack on one end and an RCA on the other.  I'm hoping this solves the problem, but I'm open to suggestions.  It's a real drag having a new toy in the house but not being able to use it!
Thanks guys,
-->grub

[grub]

problem solved........it was noise coming from the cable line.

It was a tricky problem to diagnose, but I un-hooked everything and re-connected components to my reciever one at a time.  The VCR and cable box both induced a loud, low hum in the sub amp.  Fortunately my power conditioner has a filter for coax and it took care of the problem.

FYI for others out there with a similar problem.
-->grub

[ctviggen]

If you own the house, you might take a look at how your cable is grounded.  It might not be grounded at all (my house) or grounded incorrectly (mine's now grounded correctly).

[rosconey]

yup cable can be a bitch

[StevenACNJ]

If you own the house, you might take a look at how your cable is grounded.  It might not be grounded at all (my house) or grounded incorrectly (mine's now grounded correctly).

I am not sure my cable is grounded. But how should it be grounded?

Thanks

[zybar]

Did anybody ever explain how it should be grounded?

I am getting a loud hum all of a sudden when my satelite feed is screwed into my DirecTV reciever.

George

[StevenACNJ]

Did anybody ever explain how it should be grounded?

I am getting a loud hum all of a sudden when my satelite feed is screwed into my DirecTV reciever.

George

I use a Jensen Model VRD-1FF cable TV RF isolator for my incoming cable line. Totally cleaned up all hum problems.

Link:

http://www.jensen-transformers.com/iso_vid.html