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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
128x128aurlieus
13 responses Add your response
aurlieus's avatar
aurlieus OP
11 posts
 
Thank you for that Kirkus. I hope that this weak point has been addressed by Simaudio in their newer designs.

Khalid
kirkus
502 posts
 
This is a classic symptom of interference from an AM radio transmitter. For FM and television (which uses FM for the sound), RF interference won't actually de-modulate the audio from the station.

The most likely cause of what you describe would be a mistake in the design of the ground traces or wiring on either your preamp or power-amp, whereby the RF crawling around on the interconnect shields (which is where it's supposed to be), gets somehow injected into the signal conductors.
aurlieus's avatar
aurlieus OP
11 posts
 
Hi everyone,

I have moved to a new house and NO problems! No noise, all xlr connections work just fine. Still, it would be great if someone could come up with a technical explanation of what happened at my old place.

If someone has the spare time and insight, it would be helpful for others pulling their hair out over this.

Khalid
scrith
22 posts
 
You might also consider a power regenerator from PS Audio (like the P600), which converts your home's AC power into DC and then re-generates it as AC with perfect sine waves (or something like that...check out their website for details). From what I've read, no power conditioner (including the expensive highly-touted ones) can clean a signal to the purity of the one that the PS Audio units generate, because (since they are just fancy filters) they still rely on the power being well generated (by your power compnay, I suppose).
scagneti
23 posts
 
Are you currently using a power conditioner? They can work wonders.
aurlieus's avatar
aurlieus OP
11 posts
 
Hi Nick,

It seems all my components are totally fine - they worked perfectly at the store with all the cables I use at home in balanced mode, no noise issues what so ever. Not a thing wrong with my electrical socket either, I got a Transparent Labs line tester installed on my outlet and the line was diagnosed as having no problems.

Even the most well read and hardcore stereo guru is stumped by my dilemma! No one seems to have an answer; I am hoping that if I install a new audiophile power socket it might help though chances are slim!

Still hoping,

Khalid (I may have to move house!)
nikturner920
144 posts
 
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
aurlieus's avatar
aurlieus OP
11 posts
 
Hi Nick,

It has been a rather depressing couple of weeks. Let me explain:

- I tried out the Cardas XLR and RCA caps, no luck!
- I took my pre amp to my local hi end store and hooked it via the XLR interconnects I use at home, perfect, no issues, no noise!
- I will take both my amp and pre amp to the store and basically try to recreate conditions at my house, if there is a problem then I am on the right track, if not then there is something very wrong with wiring at my house which could mean an expensive visit from the electrician!

Keeping my fingers crossed!

K.
nikturner920
144 posts
 
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. ;-)
aurlieus's avatar
aurlieus OP
11 posts
 
Hi Michael,

Appreciate the advice, unfortunately, the Quad 22L is not an electrostatic speaker, but a normal speaker, though I wish I had the money to afford a pair of electrostatic speakers from Quad! :(

Khalid
michaelhwolff
112 posts
 
If I'm not mistaken, there are small power wires that run vertically in the Quads. That's why they are electro-static speakers. I would think that this is where you antenna is.
What to do about it, I have no idea. You need Quad experts.

Good Luck,
Michael
aurlieus's avatar
aurlieus OP
11 posts
 
Hello Nik,

To answer your questions:

1. I do NOT hear any hash with the XLR connections plugged into the power amp (powered on) and plugged into the preamp with the latter switched off.
2. Changing inputs does not make a difference, Tape, CD and LP player all pick up the same amount of hash with preamp switched on.
3. I am pretty certain that the speakers are picking up radio signals (well, sounds like radio because I can hear the worst type of adult contemporary music imaginable!) and not cable signals. All the MORE reason I need to fix this!

HELP!

Khalid
nikturner920
144 posts
 
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
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