Puzzling cause of noise in system due to DAC location

HiFi Dave

Novice Member
Hi,

This is my first post here:). I have encountered a problem which is very puzzling. I hope someone on here could solve it for me, but I also came on to inform others who may also encounter the same problem. Here goes...

I setup my hi-end system, but once I connected CD transport and DAC up, I got a horrible buzzing sound coming through amp/speakers. I know the usual culprits are ground loop and mains hum afaik. Interference can also cause such problems. [Now my system has very high quality components all round from interconnects, power leads to all components.]

To pinpoint the cause of this humming/buzzing, I used one wall socket for all the system to eliminate groud loop issues. I tried different interconnects, power leads, extension leads etc. etc. I even tried different DACs. Same problem. I did, however, try something which did eliminate it. I MOVED MY CD TRANSPORT AND DAC TO THE OTHER SIDE OF MY AMPS/PREAMP. Now bear in mind all components are at the same distance (I have my own custom built rack with 3 tiers).

Does anyone know why this happens? The components are the same distance from the amps but I only get buzzing when they are on the right side as I face the system. I thought it might be to do with where the transformers are in the amp (I get same problem with 3 different DACs and 2 transports), such that when CD is on right it is nearer that/them (I'm no electronics whizz) and this causes the buzzing, so I assume it's amp-dependent. I really need a solution to this, as I am planning on putting a hiend BluRay player on the right of my amps but can't have this issue. Any advice or suggestions would be greatfully received.

Thanks,
Dave
 

Khazul

Well-known Member
Sounds like you have tried swapping everything including interconnects which is what I might have suspected (not uncommon for a damaged interconnect to be apparently fine when bent one way, but not the other, for eg due to relative equipment placement).

On the surface of it, sounds like an amp EMR/ground (lack of) issue. You dont state what make/models of equipment you have, so hard for anyone to chime in with something useful about the specific equipment.

Maybe there is a known issue with some equipment. I cant say I have ever experienced something like you describe with any reasonably well built audio equipment that isnt faulty, or is lacking a chassis ground when it should have one (some need a chassis ground and some do not - depending on their design, so cant usefully comment on that either without knowing the specific equipment).

Most of us here are UK or EU (with generally well installed mains), but are you in the US by any chance as I have come across all sorts of wierd issues on reported on forums due to dodgy mains ground wiring in the US, especially folks living out in the sticks earthing via a ground spike that probably fell over or whatever.
 

noiseboy72

Distinguished Member
This could be down to a poorly wound transformer in one of the bits of kit.

When I was building and testing audio equipment as my first job, I can across this on a couple of occasions. It was simply due to poor winding allowing significant amounts of magnetic radiation to be emitted. Usually the casework was enough to contain this, so only the piece of equipment itself was affected, but with a more open case design, I can see how this could happen.
 

wine man

Active Member
Are you by any chance using Powerline plugs to carry your router/internet signal around the house? These can be a source of interference in a system. I had to ditch mine due to a buzz/motorboat noise via the turntable/phonostage & out through the amp & speakers. Once I disconnected them the problem disappeared.
 

HiFi Dave

Novice Member
Sounds like you have tried swapping everything including interconnects which is what I might have suspected (not uncommon for a damaged interconnect to be apparently fine when bent one way, but not the other, for eg due to relative equipment placement).

On the surface of it, sounds like an amp EMR/ground (lack of) issue. You dont state what make/models of equipment you have, so hard for anyone to chime in with something useful about the specific equipment.

Maybe there is a known issue with some equipment. I cant say I have ever experienced something like you describe with any reasonably well built audio equipment that isnt faulty, or is lacking a chassis ground when it should have one (some need a chassis ground and some do not - depending on their design, so cant usefully comment on that either without knowing the specific equipment).

Most of us here are UK or EU (with generally well installed mains), but are you in the US by any chance as I have come across all sorts of wierd issues on reported on forums due to dodgy mains ground wiring in the US, especially folks living out in the sticks earthing via a ground spike that probably fell over or whatever.
I am in UK not US.
Equipment is Musical Fidelity a308cr Pre and 2 Powers. DAC is Jay's Audio DAC-2 Sig, Jay's CDT3-Mk2 Transport. I also have MF Tri Vista 21 DAC and Audio Achemy DDE3 DAC.
All 3 DACs have same noise issue on right side of amps. Note on left side, no noise at all. Using same plugs etc. etc. Amps work perfectly otherwise. If it was the issue you suggest, wouldn't it occur on other side as well?
 

HiFi Dave

Novice Member
Are you by any chance using Powerline plugs to carry your router/internet signal around the house? These can be a source of interference in a system. I had to ditch mine due to a buzz/motorboat noise via the turntable/phonostage & out through the amp & speakers. Once I disconnected them the problem disappeared.
Never heard of powerline plugs. I've got wireless broadband, but wouldn't that also make noise with DAC on left of amps?
 

HiFi Dave

Novice Member
This could be down to a poorly wound transformer in one of the bits of kit.

When I was building and testing audio equipment as my first job, I can across this on a couple of occasions. It was simply due to poor winding allowing significant amounts of magnetic radiation to be emitted. Usually the casework was enough to contain this, so only the piece of equipment itself was affected, but with a more open case design, I can see how this could happen.
You might be right, but my MF amps are built like tanks with usually great UK MF build quality. Could their age (2004?) mean they might need a service? I feel it's more an electrical problem, but can't explain it not happening with DAC on other side of amps. I've used one of my DACs (which has the problem) on my 2nd system with no issues at all. That uses Myryad amps.
 

noiseboy72

Distinguished Member
If they have toroidal transformers, then even a steel case might not stop the magnetic interference escaping.

We always had to replace the transformers when the fault was detected. We had a magnetic pickup that plugged into an oscilloscope to confirm the problem.
 

HiFi Dave

Novice Member
The transformers (that's the big, heavy coils right, I'm not an electonics guy?) are big in these amps. Expensive replacement I assume. As there is one on each side afaik, maybe it's the right one which is dodgy? This would explain the side issue being only on the right side perhaps. The auto volume control knob doesn't work, so maybe a chance to get this amp upgraded at the same time as sorting a potential transformer issue.
 

larkone

Member
Is it the routing of the interconnects that is the issue and they are picking up interference on one side and not the other?
 

HiFi Dave

Novice Member
I don’t think so, because power leads are mainly on the left side. I tried different interconnects, power leads, plug sockets, extension leads DACs, even CDTs (I have 2) The only common factor is the amps, and it is only when DAC is to right of preamp, so the problem must originate there. Most likely it is a transformer issue, but this is only speculation. Note the system works perfectly at a very high level otherwise, both channels etc.

Thanks for all trying to help me.
 

mseve1

Active Member
Sounds like its just an unfortunate 'feature' of your MF amplifiers - it may be due to a fault which has developed over time or it could even be an inherent defect in their design e.g. poor rejection of localised RFI. If you cannot permanently reposition your gear to eliminate the issue then perhaps alternative amplification needs to be considered or at least trialled to be absolutely certain that that is the source of the problem.
 

Phildick

Active Member
Have you tried it with only one amp on? Is the noise through both speakers? Does it stop if you switch your pre off?
 

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