RF Interference Question

Hi everyone,

My system is comprised of:
Klipsch Forte III speakers
Clearaudio Concept Wood w/ Satisfy CF arm
Hana SL cartridge
Cambridge Audio CXA61 integrated
Lounge Audio LCR Mkiii phono preamp with Copla SUT

I am having an issue with RF interference in my speakers when playing records, it is audible especially in the right speaker when no record is playing and I am on phono input. My integrated amp has a 3.5mm jack in front to plug in a phone/audio device; when I listen through the jack I do not get any RF interference.
Any thoughts/input would be appreciated!

 

Is it an FM radio station? Do you have long or excess length speaker or interconnects or from turntable?

 

In my experience you may want to try better shielded cables between your Lounge and Cambridge. What IC's are you using in that spot?

 

It just sounds like sounds/buzzing (no audible words I can make out).

 

Between my Lounge and Cambridge I am using Audioquest Golden Gate (universal in whole system, minus speaker cables which are Kimber Kable). Any advice/recommendations? Thanks.

 

No doubt Kimber are are top notch.
However .....
You could try a pair of Mogami
Interconnects. They are available
Through Amazon, or you can make up
Pair.
The reason I suggest this strange idea
Is that on phono with its high impedance
Is very prone to RFI.
Now kimber, may be directional.
This is known as a 'Pseudo' connection.
The screen or configuration that Kimber
Use, ie, special weave of wire strands,
Usually are grounded at one end ONLY.
Idea is that any RFI cannot travel to preamp.
However, I have found particularly
On phono, a simple well screened
At Both ends works better, where RFI,
Is a problem.
I experienced this( not with Kimber)
With Van, Den, Hul interconnects.
The guy, next door, has his modem
In the room adjacent to my listening room. This could be heard audibly
When he moved it ceased!
Of course, it may be unrelated.
RFI is unpredictable

 

Your thoughts aren't that odd as you say RFI is unpredictable, some time ago i got in some new to me long interconnects the brand isn't relevant (it was an audiophile type brand) but the fact that i discovered they by adding them into my system between phono and amp, which i had repositioned about 2 meters away from the phono suddenly i had buzzing, fortunately from reading elsewhere i decided to test a couple of things, first i tried the new cables with the amp back close where it was before the hum was gone to my ears now so i thought odd ....my daughter visited (she has much better ears than mine) said she could hear a faint buzz..so i then got some QED interconnects i already had and swapped out the interconnects and hey presto faint buzz gone in close up set up, then back to the 2 meters apart set up and nothing audible by me but my daughter heard a very faint noise, so i then got and tried some Graham Slee Lautus long interconnects and problem solved. I'm not particularly recommending any specific cable, i'm simply illustrating that in some rooms and some set ups differeing cables, with kit in differing positions give differeing results so its always worth experimenting ...

 

Does the arm tube have shielding inside it?

 

When I had noise issues between a new SUT and my phono pre I switched to Audioquest Colorado ICs with their ground noise dissipation system. It helped tremendously.

In your system definitely try the well shielded ICs between the SUT and phono pre first. In my first note I missed the fact that you had a SUT.

 

Only 1 channel is odd
Try swapping L and R one cable at a time
TT to SUT
SUT to phono amp
Etc
See if the noise follows
If not, it's not that cable
If it does, it MAY be that one
If it does not follow with any then it's a component or TT wiring, cartridge

 

Make sure the two sets of phono cables are both coaxial types.
-Bill

 

Thanks for all the answers guys! Bill, unfortunately I do not believe my integrated amp supports balanced XLR cables (I don’t remember seeing a connection for them in back but would have to check).
My main thought is that the issue may be the Kimber Kable 8PR speaker cable. They do not appear to be as well shielded as the other interconnects in my system, which are Audioquest. If I switched out the Kimbers to a more shielded speaker cable, is it possible I’d notice an improvement?

 

The high gain stuff happens at the other end of the system, and it's the high gain stuff that's more likely to pick up interference.
Does the noise stop when you unplug the TT leadout cable?

 

I doubt the problem is with the Kimber. The whole rationale behind the woven cables is that they have exceptionally low inductance. And it is the inductive part of a cable's characteristic that picks up interference. Oddly enough I did some consultancy work a few years ago comparing different cables at an EMC test facility, both for radiation and immunity at up to 1GHz. And the Kimber woven speaker cables came out at the top of the list. And shielding does not help you - it actually becomes an additional source of interference.

A very close second was Alpha Core Goertz. The flat stuff with the two copper ribbons bonded very close together.

A word of warning though - very low inductance cables which have RFI immunity trade this off against very high capacitance. That can give problems with some power amps with inadequate stability, or those amps where the designer had decided to do away with the zobel network and series inductor.

It also gave problem when I took some woven Kimber mains power cable (from my own system) across to a well-heeled friend's, and we connected it to his power regenerator. It totally trashed the sound quality - the capacitive part of the cable's impedance had put the regenerator into oscillation.

In hindsight - there is a *remote* possibilty that the capacitive load on you amp might be giving rise to that sort of behaviour. You could check by buying some really really cheap speaker cable and trying it out. That will show if your particular rig is unusually susceptible to high capacitance speaker cable.

 

I know those Golden Gates are twinax cables. I don't know if the shields are connected at both ends or floating at one end (or connected through a drain wire). If the latter, you can try better shielded cables where the shield are connected at both ends and taken right up to the RCA without a drain wire. But, FWIW, the Copla is not a step up transformer, it's an active amplifier stage, so you shouldn't have the same kind of RF issues that people more commonly have and are describing with SUTs. Is there a captive cable from tonearm to first active phono pre stage? If you're having a problem with the cable acting as an antenna, I'd focus on that cable first, given than the Copla is in fact an active amplifier. I would be surprised if the speaker cable were the source of your problem, because if it were you'd be having the problem with other sources too and you say you have no problem with a phone or other device into the mini plug jack.

 

Well, I think I may have found the issue. I unplugged the turntable lead out cable (Clearaudio Direct Wire Plus) from my Copla SUT, and the high frequency RF noise stopped. What would I need to do to fix this problem? The turntable cable has an attached ground that hooks up to Copla, and this is a high quality cable from what I know, so what is the issue? Thanks all, I appreciate your help!

 

Replace that cable first. It's the one that @chervokas and I are most convinced to be the issue. Use a coaxial cable, not necessarily an expensive cable, just one with proper RF shielding. If that doesn't cure it, then you need to investigate how the connection box there at the turntable is grounded to the tonearm tube.
-Bill

 

What happens when you have the leadout cable connected to the step up, but with the cart disconnected?

 

The cable is screened.
It's about halfway down the page Clearaudio | High End - made in germany

I suspect that the it doesn't run through the entirety of the arm, as it's quite hefty stuff.

 

Hmm, I haven’t tried that yet. I’ve never heard of this being an issue with the Hana SL on a clearaudio table. Could be worth a shot. Any other advice anyone? Appreciate it.

 

Kimber is not shielded if it's the typical 4PR, 4 VS, 4 TC variety. Same with PBJ IC's.

 

I did ask a few posts back if the armtube had internal shielding.
An enquiry in Clearaudio's direction wouldn't go amiss

 

The cable is fully shielded within the armtube on the Satisfy Carbon (I've had mine partially disassembled so have seen it), with the braided shield then carried through to the minimal aluminum headshell where it clamps to armtube. It is one piece wiring from cartridge pins to the preamp, but of course loses the shield for a length as the wires go through the pivot. If you have an ohmmeter, you can test the shield integrity from headshell to the ground wire.

I'd be inclined to ask Lounge (morinix around here) for help, I know he's helped others with similar issues. Have you tried adjusting the Copla settings? Maybe bypass the Copla head amp and plug into the LCR as a test, it won't be loud enough, but just to check if the issue is gone.

 

Thanks for the clarification

 

Clearly I don’t know my own system haha. I meant to say I am using Audioquest Big Sur (not Golden Gate) interconnects between amp and preamp, and between preamp and step-up amp. I did message Lounge Audio, the guy there did give some good tips. I checked all my connections as well as unplugged a cable box close to my system...however I am still getting this RF interference!
What I don’t understand is all my cables are shielded from what I can tell. The only thought I have is that the Big Sur’s could be the issue? If these had a high capacitance or whatever the term is, could this be introducing noise/gain/hum into the system?
I figured if it isn’t the tonearm cable it would have to be these since they connect everything together (turntable to step up amp to pre amp to integrated amp). Is my thinking correct guys? I appreciate the help