Hi everyone,

My AV2 has an annoying quirk, it's doing it now hence why I've decided to ask about it.

I'm watching a divx on my xbox at the moment connected via scart to my plasma which in turn connects via optical to my AV2. Now the volume's not loud at all (35 at the moment) and I get a background hiss almost like a radio that is out of tune. If I mute the AV2, the noise goes away. Could this be an earth issue? My AV2 went back to Naim about 4 months ago for a look over and was given a clean bill of health. I'm also using the latest firmware.

It can be really annoying when your're watching a quite scene and there's this hiss/fuzz in the background. Could the AV2 be picking up interference from somewhere? My old receivers never suffered from these kind of problems but the AV2 does seem quite sensitive from what people say to mains/earth problems.

Power-wise all my Naim kit is conncted via a Hydra from Grahams so that should help a bit. Grahams actually advised me to try maybe taking a cable from the earth pin of the hydra to an earthed surface - does anyone else have any other ideas?

Thanks for your help!

Dan

-Does it do it on all outputs?

-Does it do it will all sources disconnected? (If you are using optical, then its unlikely to be this input as its isolated)

-If its on one particular output, check its not the amps by swapping the outputs around on the AV2 (remember to power amps down before pulling DIN's out!).

-I assume you mean optical from X-Box direct to AV2

Hi there,

I dont think it's on all inputs only when the xbox is on. It is connected via scart to tv and then optical from pioneer media box to av2 just because I haven't got an optical cable long enough to go from the xbox to av2.

I know in a Naim hifi system the system earths through the CD-Player, does the AV2 earth itself or is it intended to have a Naim CD-Player attached also?

Could it be possible the xbox is creating mains interference that the AV2 is picking up rather than signal interference?

Next time I get the noise I'll disconnect the inputs and then if it's still there i'll power down the xbox, see what that does for the situation.

If you could let me know on the intended earth 'route' that'd be great.

Cheers
Dan

quote:

Originally posted by dan scott:
Hi there,

I dont think it's on all inputs only when the xbox is on. It is connected via scart to tv and then optical from pioneer media box to av2 just because I haven't got an optical cable long enough to go from the xbox to av2.

I know in a Naim hifi system the system earths through the CD-Player, does the AV2 earth itself or is it intended to have a Naim CD-Player attached also?

Could it be possible the xbox is creating mains interference that the AV2 is picking up rather than signal interference?

Next time I get the noise I'll disconnect the inputs and then if it's still there i'll power down the xbox, see what that does for the situation.

If you could let me know on the intended earth 'route' that'd be great.

Cheers
Dan

-AV2 signal ground is mains earthed if the internal earth link is not cut. This means if you connect another mains earthed device, you may get a loop. If this is the case, your dealer should be able to get info on how sort this problem.

-The interference may be on the mains...It wont be coming from the XBOX signal side as you are most likely using optical/toslink

AV@Naim - Perhaps you could supply some info RE getting rid of earth loop? I have the same problem and local dealer didn't have many ideas.

System is:

Pioneer Blu-ray player connected via digital coax and analog out (for uncompressed PCM soundtracks) to digital coax input and VIPS, respectively, on AV2.

Pioneer player connected to Sony Pearl projector via HDMI. Pioneer player has no earth pin on mains input socket but Sony projector does have earth pin on mains input socket. Hum cured by removing mains lead from projector...

Rest of system is 282/CDX2/555PS/175/200.

Earth loop hum present on all inputs of 282 but worst on AV input.

I see that there is an earth binding post on the back of the 282. Can this be used in any way to alleviate earth loop problem...?

Thank you

Billy R

quote:

Originally posted by Billy Rubin:
AV@Naim - Perhaps you could supply some info RE getting rid of earth loop?
Billy R

I cannot post any information concerning the internal link on our forum.

Your naim dealer should either know how to do this or be able to contact us and find out. We don't want end-users taking the lids off and zapping the units or themselves...

What you can do though, is disconnect sources in sequence and find out which is causing the problem.

I am having the same problem with AV2. All was well when the AV2 was connected to NAP175. Of late, I changed my centre speaker to Aerial CC5. At the same time, I upgraded to Theta Dreadnaught 5 channel amps (only using three modules to power centre and surround speakers since using the unity gain input on my 552 for front speakers). The Dreadnaught is earthed. An immediate hum occurs on the centre and surround speakers, Dreadnaught has both balanced and single line input and shorting pin 1 and 3 on the balanced input does not help. I suspect it is due to the grounding of the signal negative input connectors on the AV2 to the mains earth ground that cause this earth loop. In order to avoid hum-loops the signal negative of the whole system should be connected to the mains earth in one place. This is probably the reason why for NAP 175, the signal negative is not connected to the mains earth.

I have checked another AV processor, Tag Mclaren and the signal negative is not connected to the mains earth. But shorting pin 1 and 3 on the Dreadnaught does eliminate the hum.

AV@Naim, is the hum caused by the grounding of the signal negative input connectors on the AV2 to the mains ground earth?

Many thanks
KC

On a lark, try disconnecting all sources from the AV2–does the hum go away?

You should also try using pins 2 & 3 (pin 2 = signal, pin 3 = signal ground, NOT shield, pin 1 = shield, assuming a two-conductor shielded cable). This is no guarantee, however.

Dave's correct. If you use 2 and 3 of the xlr at the dreadnaught end, any earth loop to the amp "should" be broken. On the tag unit, shorting 1 and 3 gives the av bit an earth so ought to stop any hum.

In answer to the last question: no, it's caused by there being (at least) two earths in the system, which is pretty common in av setups.

(Always consult your dealer or qualified personel before ANY earth modifications...).

Thanks Dave and AV@Naim. This works.

mine is still doing it... watching Blade Runner at the moment and this is a good example as it has quite a few quiet scenes. It's like a crackle in the background the actual dialogue/effects aren't crackling it's in the background almost like an LP playing. Really frustrating! It's definitely coming from the AV2 as I have tried different power amps. I can't get my dealer who sold me the AV2 round as I have moved after buying the AV2 and don't live near them at all...

Any ideas? I might try a different wall socket but I'd have to plug an extension lead into the socket and the hydra into the extension which isn't ideal as there aren't any other sockets in reach with the hydra alone.

different socket... still there

The unit may well be faulty, perhaps a trip back to Salisbury may be in order...

it came back not too long ago and got a clean bill of health (Albeit with a firmware update)

I'd really like to try another AV2 side by side here to see if it has the same problem, just too far away from where I bought it...

Really frustrating when watching a film like Blade Runner where it's bit quiet so you've got to turn up the volume a bit.

Also it stops if I stop or Pause the DVD player (Happens with other inputs also)

Any ideas of what may be at fault?

Thanks
Dan (Going a bit round the bend )

quote:

Originally posted by dan scott:
it came back not too long ago and got a clean bill of health (Albeit with a firmware update)

I'd really like to try another AV2 side by side here to see if it has the same problem, just too far away from where I bought it...

Really frustrating when watching a film like Blade Runner where it's bit quiet so you've got to turn up the volume a bit.

Also it stops if I stop or Pause the DVD player (Happens with other inputs also)

Any ideas of what may be at fault?

Thanks
Dan (Going a bit round the bend )

-Have you got another optical source you can try, just to confirm if its actually the source or not?

-Is your aerial installation mains earthed?

-What exactly is connected to what (and how) in your setup (all sources/TV etc)

-If it stops when you pause this points to either the processor in the AV2 or the XBOX...

Hi AV@Naim

I was mistaken, my problem is not resolved. Shorting pin 2 and 3 did not help. In fact it kills the sound, no output from centre or surround when pin 2 and 3 on the Dreadnaught are short, hence no hum either. I did not do a proper short by soldering pin 2 and 3 on the XLR (I didn't have spares XLRs at the time). I used a temporary wire to short the pins so occasionally the wires were not touching the pin properly. Tonight I have soldered 3 XLRs shorting pin 2 and 3, and there are no sounds coming from the speakers.

Dave said to USE pins 2 and 3, NOT short them.

should have the -ve (earth) wire to pin 3 and the +ve (signal) wire to pin 2 on all Dreadnaught xlr's.

The shorting refered to the Tag...

Also note he said: "This is no guarantee, however"

AV@Naim

Sorry my mistakes for not making it clear. As you may know, Dreadnaught has both XLR (balanced) as well as RCA inputs. I am only using the Dreadnaught to power the centre and the surround speakers hence only 3 power amps modules are employed. Currently I have modified the interconnects for the centre and surround channels to RCA inputs on the Dreadnaught. I therefore misunderstood Dave's and your comment about using pin 2 and 3 to mean shorting them. Are you suggesting that I do not use the RCA inputs on the Dreadnaught but use the XLRs balanced inputs instead?

Thanks

KC, where are you located?

Hi Dave, I am from Singapore

I'd definitely see your dealer on this one.

Dave

I already have and in fact they have written to Naim as well. Thanks

quote:

Originally posted by AV@naim:

quote:

Originally posted by dan scott:
it came back not too long ago and got a clean bill of health (Albeit with a firmware update)

I'd really like to try another AV2 side by side here to see if it has the same problem, just too far away from where I bought it...

Really frustrating when watching a film like Blade Runner where it's bit quiet so you've got to turn up the volume a bit.

Also it stops if I stop or Pause the DVD player (Happens with other inputs also)

Any ideas of what may be at fault?

Thanks
Dan (Going a bit round the bend )

-Have you got another optical source you can try, just to confirm if its actually the source or not?

-Is your aerial installation mains earthed?

-What exactly is connected to what (and how) in your setup (all sources/TV etc)

-If it stops when you pause this points to either the processor in the AV2 or the XBOX...

Hi there,
1)This wasn't an optical connection this time it was my DVD Player over coaxial, I have got another optical source and next time I get the noise I'll switch to it and see what happens.

2) Aerial Earthing - my aerial is a little portable job that sits near the TV - can't see how it would earth so I guess it isn't - still never affected any previous AV kit I've had.

3)Connections-

a) NA CD3 via AN1
b) Pioneer 436XDE Plasma via OPT1
c) XBOX into Pioneer Plasma over Scart then through optical from Pioneer plasma into OPT1
d) HTPC via coaxial into CO2
e) Arcam DV79 into CO1
f) Apple Airport Express into OPT2
g) Arcam Alpha 5 Tuner into AN4 phonos

thats the lot at the moment.

4) When I was watching Blade Runner on the Arcam DV79 the other night the noise would stop if I pushed pause on the Arcam. The volume was at about 35-40 by the way.

If it were a dirty mains issue would the noise stop when I pushed pause?

Thanks again, I appreciate the help, just a bit miffed at spending so much money and having these issues.
Dan

I'm listening to a CD and it's there now, if I stop the CD and turn the volume up to 45 I can hear it as per the other night. I'll unplug things from mains and the AV2 see what happens...

just unplugged all mains apart from the Naim kit and it's still there...

Also unlugged the inputs from the AV2 while they were still powered up and no change.

Dan,

-what kit is connected on the outputs of the AV2 (amps/leads)?

-is this a 5.1 system or stereo?

-is noise specific to certain channels

-also is your AV2 integrated into a 2-channel system via AN3 input (output to a pre-amp for front channels)

-unlikely to be mains borne noise as it goes when you pause DVD. Its either the source device, the processor in the AV2 or possibly instability between AV2 and amps/pre-amps (depending on your answer to 2 and 3 above)

Hi there, answers as follows -

1)Fronts : NAP250 (Has also been a NAP150 which exhibited the same problem)

Centre, and Surr. - NAPV175

Both connected via black snaics.

Front speakers - Ariva
Centre speaker - N-Cent
Surr. speakers - N-Sat's

All connected via NACA5

That's about it output wise - can't think of anything but speakers that takes a signal from the AV2, everything else just provides one to the unit.

2) Seems specific to the front channels although I listen in stereo more than 5.1 (And Blade Runner that I was watching last night is a Dolby 2.0 soundtrack) It is unlikely to be the 250 as I had the same problem with the 150.

3) No extra preamp at the moment - I've had a 202 and a Nait5i there before but it's just the Av2 at the moment while I explore some options for a music only Pre.

4)I've seen it on different sources ie XBOX and Arcam DVD player so unlike ly to be both (Although never say never I guess)

Thanks again
Dan

Sorry of course the 250 isn't a black snaic it's a black cannon - DIN cable (Made by Naim) I always forget the 250 isn't a DIN connector.