rfi rfi and ... rfi

Posted by: Philippe Dancause on 22 September 2002

Hello to you all,

I currently have a 180/hi/72/ Cal audio Alpha Dac and Dx-1 CD system and have experienced incredible amount of rfi since getting the naim components. I know these are wide band things but the buzz is simply too loud (if you want to sleep in the house ;-))

I have read everything there could be on this forum and tried all I could.

-I have a good main (tested)
-I have no grounding problems
-I have no tv or radio in the room
-I have come to know "by sound" almost all appliances in the house.
-I have tried audioquest rf stoppers with mixing results (but they help a bit)

There are many radio and tv emitters about 1km from my house (the complexe G in Québec for manu and other queberquers) and the buzzing sound come and got when I move cables (especially the SNAIC 4 between 180 and hi and speaker cables).

All this story for this question :
As any of you tried Naim's anti-rf kit? I know there are many "layers" of shielding (with growing detriment to the sound as you go).

I know I will lose some of the qualities of naim but:

- I guess that a naim with the anti rfi-kit and a bit less PRAT is better than no naim ...
-I can maybe offset the detriment by dressing the cables properly (which is impossible at the moment... they are dressed against rfi, not for sound).

Thanks for your help, experience and encouragement!

Philippe
Québec City

[This message was edited by Philippe Dancause on SUNDAY 22 September 2002 at 17:27.]

Posted on: 23 September 2002 by Philippe Dancause

Am I the only one with this kind of problems?
confused

Posted on: 23 September 2002 by Thorsten

possibly you're one of the few. maybe you should wait a bit longer for a qualified response. sorry, that i can't help, but at least i wanted to comfort you, that we do care. unfortunately i cannot help. i do have a buzz coming from my system and interferences on my nait via headphones. thank god as soon as the music starts i do not hear it anymore. as for the buzzing when there's no music - i switch off the poweramp if it disturbs me. don't give up.

The most important upgrade: Forget about your system.

Posted on: 23 September 2002 by David Hobbs-Mallyon

Philippe,

Are you sure this is RFI? Where is the buzzing noise coming from? If it is coming from the Naim transformers, then you may have some earthing issues.

David

Posted on: 23 September 2002 by Frank Abela

This doesn't sound like an RFI problem to me. Do you hear people talking/singing/music playing? That's usually how RFI shows itself. If it's a buzz (or hum), then it's more likely some other problem.

Also, I've heard of RFI off phono stages since they're very low input with lots of gain, but never at line level.

If it is just a buzz or a hum, it's more than likely an earth loop. In this case, try to plug in your system in a different order to break the loop. Usually we try to plug in all the components on a single four- or six-way block (no filters) so all the earths are on the same potential (or as close as possible).

Regards,
Frank.
All opinions are my own and do not reflect the opinion of any organisations I work for, except where this is stated explicitly.

Posted on: 23 September 2002 by Philippe Dancause

David:

no, it really comes from the speakers. No buzz at all from the boxes.

Frank:

If I do not play with cables I can sometime ear voices. However, with cables tightly coiled or put together, I just ear humm. Everything is pluged in a 6 outlet block directly in the wall . The ground has been tested.

Posted on: 23 September 2002 by David Hobbs-Mallyon

hmmmmm,

Guessing then. But assuming you've got all the connections right, the only time I've had sounds like that is when I've had a slightly dodgy connection between hicap and power amp. Try remaking the connection and see if that makes any difference.

David

Posted on: 23 September 2002 by Andrew L. Weekes

I can assure you we all care, but this is a very difficult problem to diagnose remotely.

It is your dealers responsibility to get the equipment working to your satisfaction within your home, if your dealer is local, he will have no doubt experience these problems previously.

Andy.

Posted on: 23 September 2002 by Frank Abela

Philippe

I see you are using a 72. Are you using a record deck? If not, can you check inside the preamp for MM or MC boards? If you have boards in there, and you are not using a record deck, you can take them out. They would have the number 322 or 323 on them. You may be suffering from a combination of crosstalk and RFI. I just can't believe there's so much radio energy in your area to cause RFI at line level.

You need to work out which item is causing the problem. Does the hum go away if you mute the preamp? If not, then we know it's hicap/180. If so, then unmute and unplug (from the wall) either the dac or the cd transport and see what happens. Eventually you should be able to isolate the source of the problem. However, Andy makes a good point and you may be better advised to get your dealer o have a listen.

Regards,
Frank.
All opinions are my own and do not reflect the opinion of any organisations I work for, except where this is stated explicitly.

Posted on: 23 September 2002 by Philippe Dancause

These are all good points. I will do some experiments this evening.

I have also called my dealer which should come over new week. It is a second hand system which I haven't bought there but Cora (the naim dealer in Quebec) has been my dealer for all my other components. The price to pay and have expert advice will be well worth it.

I guess we all have this need to understand how things work and try to resolve things on our own! Haven't we all tried to build an Ikea table without the plan

thanks again, with your advices I will at least be helpfull to my dealer with he visit me.

Phil

Posted on: 23 September 2002 by Manu

Philippe,

Bonjour.
What other souces are pluged on your system: turntable, ...?

Maybe, your system is not grounded (signal ground is floating).
Naim systems are grounded at the source (CDP), nowhere else. So, your CDP must be grounded, I mean signal ground must be earthed at this stage. In your case, you use a separate Transport/Dac, the DAC must be grounded, not the transport. The grounding path is sometime lost with a digital connection: optical link, transformer output coax.
Is your DAC using a grounded AC plug or only a 2 blade one?
Mail me if you need more info (in french).

Emmanuel

All opinions are my own, and reflect those of the organisation i work for, even if not stipulated.