buzzing sound,arcam ir dac/naim nait 5i

[hoojtune73]

just wondering if anyone could help with this one.

just bought a nait 5i amplifier second hand and hooked it up to my arcam ir dac,project debut 3 turntable with cambridge audio phono stage.

all sounds very nice indeed but with the dac running i get a noticable buzzing/humming noise similiar to what you would get if you forgot to connect the earth lead with a turntable,ive tried swapping interconnects around but to no avail.

any possible suggestions would be greatly appreciated

matt

 

[davedotco]

You need to tackle this in a logical and methodical manner.

Firstly disconnect everything from the amplifier bar the speakers.

Then connect each component to confirm that it is indeed the dac that is causing the problem. Ie as you connect everything, one piece at a time, at what point does the buzz appear.

Assuming it is the dac, I am guessing it is connected to a computer or streaming device of some sort, can you confirm what that is.

Can you also say how this is connected and also what happens with the dac connected to the amp but with inputs unplugged.

 

[hoojtune73]

thanks for the quick reply davedotco

the dac is being fed via a laptop through a 5m long qed usb cable and chord carnival interconnects to the naim

i disconnected the dc power supply from the dac,still there,disconnected the usb as well then the noise disappeard,plug just the dc back in then it comes back.

its all connected to a fairly cheap mains conditioner if that would upset proceedings somehow,the stangest thing is there is none of the normal faint phono buzz you can get from a phono stage.

the hum is not over powering but knowing its in the background is annoying

 

[davedotco]

thanks for the quick reply davedotco

the dac is being fed via a laptop through a 5m long qed usb cable and chord carnival interconnects to the naim

i disconnected the dc power supply from the dac,still there,disconnected the usb as well then the noise disappeard,plug just the dc back in then it comes back.

its all connected to a fairly cheap mains conditioner if that would upset proceedings somehow,the stangest thing is there is none of the normal faint phono buzz you can get from a phono stage.

the hum is not over powering but knowing its in the background is annoying

OK.

It sounds that you have an earthing issue or possibly RF interference.

First thing to try is to see if you can disconnect the earth from the mains lead of the dac power supply, this is a long shot but worth trying assuming it has a three core mains lead.

If the mains is only two core or dropping the earth makes no difference than you need to try dropping the earth on the nait. The mains lead may well have a molded plug, so see if there is a similar lead elswhere in the house (a kettle lead will do) with a screwed mains plug. Undo the plug and disconnect the earth, make sure it can not short either live or neutral, and try that.

If none of that works, it may be that your dac is picking up noise (RF) from somewhere, try and borrow a different dac and try that.

Other points to bear in mind is that 5m is rather long for a usb lead, try a shorter one if you can (move some of your kit, temporarily anyway). Also if it is possible try connecting computer to dac with an optical lead, this will isolate your computer from the hi-fi in electrical terms.

Try and maintain a clear head here, change one thing only at a time and test each time.

 

[hoojtune73]

ok,will have a delve into those lines of thought,bit worried about not having the amp earthed tho

maybe a couple of beers and forget about the background noise eh!

just put the old cambridge dacmagic in line and same result.will have a ffiddle about and update you

thanks again

matt

 

[davedotco]

ok,will have a delve into those lines of thought,bit worried about not having the amp earthed tho

maybe a couple of beers and forget about the background noise eh!

just put the old cambridge dacmagic in line and same result.will have a ffiddle about and update you

thanks again

matt

OK.

You need to disconect the usb cable from the dac and leave things for a short while. If things are still buzzing it is probably an earthing issue. The dac power supply probably has a two core mains, you can you check this quite easily.

If you have another pair of phono/phono leads you should try them too, then if that fails the only thing to do is to is to get an iec mains lead and wire it up without using the earth. Any lead with a screw together plug will be fine, cut away the earth lead so you are effectively using a two core cable.

Try that and update.

 

[hoojtune73]

hi davedotco

tried it taking the earth away for a short time but the phantom buzz still there

what is more annoying is the turntable/phono pre amp is dead quiet even with the plug earth terminal connected

im wondering maybe if i whent phono to din from the dac this may solve it,toatally clueless tho on the pros and cons of din connectors tho,the last time i saw that style of jack were the speaker outputs on my grans 1970s music centre!!

the joys of being a naim newbee maybe??

 

[davedotco]

hi davedotco

tried it taking the earth away for a short time but the phantom buzz still there

what is more annoying is the turntable/phono pre amp is dead quiet even with the plug earth terminal connected

im wondering maybe if i whent phono to din from the dac this may solve it,toatally clueless tho on the pros and cons of din connectors tho,the last time i saw that style of jack were the speaker outputs on my grans 1970s music centre!!

the joys of being a naim newbee maybe??

It is begining to look like your dac is picking up some sort of RF, difficult to sort. I would try different interconnects to make sure but it sounds like RF at the minute. Don't suppose you have got a different amp you can try, Naim's earthing system is not always the most predictabe.

 

[John Duncan]

Is your laptop plugged into the mains? If so, what happens if you run it off battery only?

My Sony laptop hummed horribly via its headphone output and wasn't completely cured via USB, but it went away totally when running off battery instead of mains.

 

[hoojtune73]

thanks for that,even just the dc power cord to the dac connected without usb input still gives the noise

thought sod it tonite and put the rotel amps back on the rack and not a buzz,hum or crackle to be heard!

perhaps the naim is just a bit to exotic for the lower priced front end.

be interesting to see if the £1250 naim v-dac did the same...

must be annoying for you having to plug in and charge up every couple of hours

 

[davedotco]

thanks for that,even just the dc power cord to the dac connected without usb input still gives the noise

thought sod it tonite and put the rotel amps back on the rack and not a buzz,hum or crackle to be heard!

perhaps the naim is just a bit to exotic for the lower priced front end.

be interesting to see if the £1250 naim v-dac did the same...

must be annoying for you having to plug in and charge up every couple of hours

Ah, the old Naim earthing problem. In the 'old' days, Naim amplifiers would keep signal and chassis earth separate, in fact the casework was normally earthed through the record player. A cause of much confusion.

I thought they had this all sorted by now, but clearly not.

Get rid and buy a 'proper' amplifier....... 😉

 

[hoojtune73]

what would you call a proper amplifier?

to be honest,theese rotels are banging this eve after a few days of naim integration

 

[brandmartyr]

Hi, It's an earthing problem. I have the same with the same amp and arcam rLink.

crudest but simplest solution - some earthing wire wrapped or connected to one of the dacs unused connectors and hooked to the earth pin of the mains plug.

Cheers

m

 

[hoojtune73]

thanks m,that simple eh

my only worry with that would be that if ther was an earth fault in the house i could get a couple hundred amps trying to find its way to the mcb/rcd via my dac:dance:

could hope for no electrical faults tho and eliminate that hummmmmmmm

will give it go

matt

 

[davedotco]

thanks m,that simple eh

my only worry with that would be that if ther was an earth fault in the house i could get a couple hundred amps trying to find its way to the mcb/rcd via my dac:dance:

could hope for no electrical faults tho and eliminate that hummmmmmmm

will give it go

matt

It's not, most likely the Naim. This used to be an issue years ago but I thought it had been sorted. The substitution of the Rotel rather proves that.

The earthing strap mentioned may work, the dac case is plastic I believe so you need to find a solid earth point to attach the wire, just connect the other end to the earth pin on a spare 13 amp plug and plug it in.