Another RF Interference Question

We need Huge on this thread...

But for now option C is probably the one to go by. You seem to be picking up 'dirt' from your mains.
One thing intrigued be with your option D - isn't your current mains properly earthed? NAIM equipment requires 3 wires: Live, Neutral and Earth.

Adam

Have you tried changing the groud switch setting?

yeti42 posted:

Have you tried changing the groud switch setting?

If the SU is the only unit in the system,  the ground switch must be set in the 'chassis' position

Adam Zielinski posted:

We need Huge on this thread...

But for now option C is probably the one to go by. You seem to be picking up 'dirt' from your mains.
One thing intrigued be with your option D - isn't your current mains properly earthed? NAIM equipment requires 3 wires: Live, Neutral and Earth.

Adam

As it's picking up radio interference, does earthing have any relevance? It's surprising that an SU is afflicted by this, as it's usually sensitive phono stages. If it is the speaker leads, you could try moving them around. 

It's easy to change and it will make a difference or it won't. Must is a little strong, it will probably sound best on chassis but no need to even check what its labelled as if it means moving the box to do so, just try the other setting.

Hungryhalibut posted:

Adam Zielinski posted:

We need Huge on this thread...

But for now option C is probably the one to go by. You seem to be picking up 'dirt' from your mains.
One thing intrigued be with your option D - isn't your current mains properly earthed? NAIM equipment requires 3 wires: Live, Neutral and Earth.

Adam

As it's picking up radio interference, does earthing have any relevance? It's surprising that an SU is afflicted by this, as it's usually sensitive phono stages. If it is the speaker leads, you could try moving them around. 

Of course it wouldn't. That's why I was intrigued by OP's point D.

'must' is a figure of speech where I learned english Yeti,  just a local language quirk.  

HH is right this kinda interference is normally a TT phono stage problem,  if the OP description is correct & nothing else is connected other than speakers,  then its speaker cable or a defect in the SU.   I would check the speaker cables & include replacing them with a temporary rig cable,  anything will do, mains cable, bell wire & if needed move the speakers closer to the amp to do that.   I wonder how long the speaker cables are & what make/model.  

Sorry, new to all this RFI stuff and was trying to gather as much information by searching before posting. Guess the earth grounding doesn't matter. But if I add a turntable, it probably would?

I did try and toggle the grounding switch but it didn't make any difference.

I'm using Bluejeancable 10AWG White (Belden 5000) - 12ft length each.

I will try and find a different set of speaker wire and test that out.

tufts0207 posted:

I'm using Bluejeancable 10AWG White (Belden 5000) - 12ft length each.

Belden 5000 is a good cable & it's not looking like thats is the problem,  but go ahead & try a swap.   After that we are looking at checking mains  power supplies & earth grounds,  try it on a different outlet etc..   Then I would question the SU itself, have you double checked the external inputs are all off etc.,  gone thru the manual & check settings one more time.     

I turned off the FM input. There is no FM antenna hooked up. I will try and turn off all the other inputs manually as well.

Out of interest - do you still pick up the weak local radio signal if you disconnect the speaker cables at the amp end and use the headphone output only ?

Just plug in a pair of headphones with the speakers unplugged? I can try that too when I get home.

Is the hissing noise also normal? I read in other threads that this is expected when close to the speakers. My friend has a UnitiLite and does not have this problem with his Totem speakers. 

I was going to take the unit to his place and see if he has the same problem and likewise test out his UnitiLite at my place to try and isolate if the SU is defective in some way.

The hiss is normal. 

tufts0207 posted:

I was going to take the unit to his place and see if he has the same problem and likewise test out his UnitiLite at my place to try and isolate if the SU is defective in some way.

Good plan  !!!!    do it both ways

But per HH,  ear close to the speaker & some low level hiss is normal.  NPR break thru is not normal.

Of note, I just spoke with someone at BJC and apparently my location in Seattle, I am in very close proximity to some strong radio towers that I'm getting blasted by. Anyone have a suggestion on shielding from RF signal for the whole SU? Is this possible? 

The SU is pretty well shielded in its aluminum case & thats connected to earth ground - assuming that is actually a good connection to the house ground & another item worth double checking.    You could try some shielded speaker cables - Chord have them, plus a few others but high price compared to BlueJeans & if that doesn't work I would feel bad.   How far from the transmitter does your UnitiLite buddy live,  if its a few miles further out,  then take your cables & he bring his along with the SU & UL as part of the comparison test,  that'll give you a clear(er) answer

He lives 3/4 of a mile away but down hill from where I'm at near the radio towers.

Ran some tests...

1. Couldn't hear any RFI through the headphones
2. Will try the switch of cables and units tomorrow

Of note, my B&W have HF and LF posts. When I remove the connecting plate and only plug into the LF, the RFI is gone. Mostly, because the RFI is only audible in the tweeter and less going down the speaker.

Next, I replaced the plates and capped the LF and connected the HF. I think the RFI is a little less, subjectively, but still present. 

I think this localizes the issue to the HF connection, but I'm not sure what to make of this. The amp is amplifying and demodulating the high frequency RFI and therefore it's prevalent in the tweeter? I don't know if that's the correct interpretation or not. It doesn't appear as though the power line is the issue right? 

Any benefit to testing the system with a line conditioner?

Thoughts?

Thanks for all the help. I might be relegated to dealing with the residual RFI at this point. Music sounds great still, I guess its mostly an annoyance that I find myself listening for the RFI in the quiet parts of music rather than enjoying the music as a whole.

Guys, if the OP can hear faint radio, that is called Radio Breakthrough and is not usually RFI. The two can be caused by quite different reasons and manifest themselves in different ways..

i do suspect if it is Radio Breakthrough and is not volume or input dependent then it is probably more to do with some sort of tuned circuit being created between the amp output, speaker cable, speaker and amplifier mains earth.. Unless I have missed it, I didn't see what speaker cable is being used. Is it at least 3.5 m per side NACA5 cable? If it is can your dealer give you a different length to try ? And if not NACA5 can you borrow some?

Ensuring the cable is not coiled and layed out in a different orientation might be worth trying after you have tried different lengths of NACA5..  along with plugging the amp into a differently positioned mains socket.  The aim here is to 'break' the resonance of that amp/speaker cable/speaker tuned circuit..

i have had Radio Breakthrough once, albeit self inflicted, and that was on the magnetic cartridge phono input.... a few ferrite hoops dealt with that... but that was specific to my phono setup.

Simon

Simon, you missed it, it's blue jeans Belden 12awg, whatever that might be. 

Nigel thanks.. ok my  advice to the OP  is definitely try and borrow at least 3.5m of NACA5 per channel ... I suspect the issue will disappear.. along with the tuned circuit resonance...

tufts0207 posted:

He lives 3/4 of a mile away but down hill from where I'm at near the radio towers.

Couldn't hear any RFI through the headphones

Of note, my B&W have HF and LF posts. When I remove the connecting plate and only plug into the LF, the RFI is gone. Mostly, because the RFI is only audible in the tweeter and less going down the speaker.

Any benefit to testing the system with a line conditioner?

I'm pretty sure this is radio breakthrough from your nearby NPR transmitters,  your buddy 3/4 mile away is not going to be too different, 3 or 4 miles might have been better.

The fact that its not on the headphones is indicative of your speaker wires &/or speakers are picking this radio breakthrough.  & yes I would have expected to get this from the tweeter only.   Belden 5000 series is sensible nothing fancy speaker cable & it has middle of the road capacitance & inductance,  its twisted pair construction should help reducing any RF effects,  but obviously not,  It will be interesting to try other cables & your buddies cables to see if a different make & construction changes your problem.  Also if possible a different cable routing direction or a single loop in the cable  will be worth trying.    

No a line conditioner will not help.  

tufts0207 posted:

Just plug in a pair of headphones with the speakers unplugged? I can try that too when I get home.

Is the hissing noise also normal? I read in other threads that this is expected when close to the speakers. My friend has a UnitiLite and does not have this problem with his Totem speakers. 

I was going to take the unit to his place and see if he has the same problem and likewise test out his UnitiLite at my place to try and isolate if the SU is defective in some way.

Glad you tried disconnecting the speaker cables and trying 'phones as you've found the source of your problem - sounds like you have a difficult location with the transmitters that close. Do you have a local dealer who can let you borrow some Naim speaker cable (which may help) or alternatively dealt with this problem before. As others have mentioned above, simple re-orientation of the speaker cables may solve the problem. Good luck. 

James

Please check that you only have one mains earth connection in the system.  Sometimes the NAS enclosure is also connected to mains earth; if you then use shielded Ethernet cables and a shielded network switch, it will create an earth loop.  This can also allow RF breakthrough.

If you have this problem I suggest trying an unshielded (UTP) cable from the NAS to the switch.

If this doesn't fix the problem you could try using an AudioQuest star quad speaker cable (such as 14/4).

Another thing to try is using 'clip on' ferrites on the Ethernet and speaker cables.  If all else fails, take a clip on ferrite and feed the individual 'legs' of the speaker cable through in opposite directions (this creates a DM choke).  The best ferrites I've found are those made by Würt Electronic.

tufts0207 posted:

Of note, I just spoke with someone at BJC and apparently my location in Seattle, I am in very close proximity to some strong radio towers that I'm getting blasted by. Anyone have a suggestion on shielding from RF signal for the whole SU? Is this possible? 

Aaah, now we're getting to the bottom of it. Welcome to Naim ownership in Seattle! Stop by Hawthorne and talk to the chaps there, and you'll get the answer that your issue is business as usual. My 110/Naca5 pick up local stations like you wouldn't believe - drives my wife bonkers sometimes. I'm just down the hill east from the Capitol Hill towers. Matt at Hawthorne said if I wanted he could solder some RF caps in, though it may or may not solve the problem, and may make the amp dynamics slightly worse. I've told my wife if it really bothers her that much then we can certainly go amp shopping together.  

I'm about to invest in some Tellurium Q (either black or super blue) speaker cable, so will be interesting if that makes a difference rf wise. Probably not, but at least it will be easier to tidy up the extra length.