XLR cables are picking up radio/TV hash...


Hi everyone,

This is an ongoing dilemma so I'll try my best to be short and to the point. I recently got 1 m Cardas Neutral Reference XLR to use between my Sim Audio W-5 power amp and my Marsh P2000b preamp. My system sounds a lot better, but I am picking up audible radio and/or television sounds on my speakers (Quad 22l). I do not have a functioning cable tv connection (I don't have a television, period!) but my power outlet is near a cable tv jack. Could this be the problem? I read on some other fourm that the cable connection may need to be grounded.

I have tried to go troubleshoot in a thorough fashion; I tried using cheat plugs; I disconnected all my cables, power cords and speaker wires, then reconnected them slowly. I discovered that only when I powered up my preamp did I got noise...and it did not increase or decrease whatever I did with the volume knob. Something is obviously acting as an antenna and picking up signals.

I think this may be a problem unique to the Sim Audio W-5; it has two sets of RCA connections, where, if you choose you can use both sets in a sort of single-ended "balanced" configuration. There are two dummy plugs inserted into the negative inputs, and the positive inputs are used in a normal single ended configuration. Thing is, I had no noise when using the Marsh and the Moon in single ended mode. I am certain that my new Cardas cables are fine...I had them checked out at a dealer...I also replaced them with a brand new pair of Transparent balanced cables with the same resultant hash. I did find that if I placed the two dummy plugs into either the left or right set of RCA connections I did not get any hash on that channel but it obviously degraded sound quality as it shorted out that particular channel.

I have had suggestions ranging from changing my preamp with another balanced one to check to see if that is having problems, to using Cardas caps to cover unused XLR and RCA connections, and even clamping ferrite clamps on the XLR interconnects.

Also, I am using a Rega Planet 2000 (in single ended config) and a Rega Planar 3 with a Pro-ject Phono Box SE; I am pretty sure they are not the cause of my problems but I am just being thorough for the record!!

Please help!
Thanks,
Khalid
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Showing 3 responses by nikturner920

To be clear, you hear these sounds with the pre-amp > amp > speaker (no sources connected, power turned on) BUT not with just amp > speaker (power on)? Does the sound change if you change inputs on the pre amp?

Nik
Khalid,

It's your pre-amp's xlr outputs. Contact Marsh and see what they say, could be something miss wired internally that is ok when you run single ended. I don't understand your 'jumper' description, I thought newer W-5's had a switch to select xlr or rca inputs. It's a bummer problem since both your W5 and the Marsh are suppose to have improved sound if run balanced. Go back to SE connection in the meantime so you don't go crazy. ;-)
Good luck, sounds like a nightmare. There are electric plug testers that just plug in the wall and give you green light or red light to check wiring. Just ask at a hardware store. Taking the whole set to the shop or at least some friends house may be the only way to figure it out.

Cheers, Nik