ground noise problem


#1

Hi,

I’m a happy new DS user(the best digital playback experience in my home!!!) but find very bothering ground noise from it. When using previous DAC, there is no such problem. Now I tentatively use a power cord without ground to solve this problem.

My connection configuration is Cubox (USB) -> DS -> Passive Pre -> Power Amp

Is it a fault unit?

Thanks

Morris


#2

Ground loops are a pain but they do not mean that there is a fault in the equipment. You do have at least two pieces of equipment that are at different potentials to ground. What happens to the hum if you disconnect the Cubox (with which I am not familiar)? Lifting the ground on one piece of equipment may be the best solution. PS Audio has made power cables with removable ground pins for that very reason.


#3

I’m afraid that something is disconnected during transportation or any component breakdown. Also, if there is no grounding, is it still protected from external EMI influence?


#4
bighead1707 said I’m afraid that something is disconnected during transportation or any component breakdown. Also, if there is no grounding, is it still protected from external EMI influence?
It's still grounded or you wouldn't have a ground loop :) Typically everything is connected by interconnects, etc. which tie the grounds together.

If you have the option of using balanced cables they may help to lower any common mode noise between the DAC and the preamp.


#5

FWIW, I had a bad ground loop hum with my PWD, and I had to lift the ground on PWD to stop the hum. I never liked the sound with the ground lifted - it seemed to add harshness to the sound. When I replaced it with my DirectStream, the ground loop disappeared and I can run the DirectStream properly grounded with no hum. No other components, interconnects, or power cords changed in my system-- just replacing the PWD with the DirectStream.

Point being, you need to swap in a different source component to confirm it is the culprit, but based on my personal experience withe my PWD, it is entirely possible that your unit can be causing the hum. -Jeff


#6

Hi Ted,

Glad to receive your reply:“It’s still grounded or you wouldn’t have a ground loop Typically everything is connected by interconnects, etc. which tie the grounds together.”

If everything is grounded together, why does my DS output ground noise? BTW, that noise comes out even I switch it off by switch at back but connect it to power bar. very strange. Without DS, my system is very quiet.


#7

Ground loops can be frustrating and often appear to avoid rational explanation. As in this case.

The problem is you have at least two different ground voltage potentials. This often occurs when an antenna (or cable for Internet, cable TV, satellite, etc.) which is grounded separately from the main box is connected to something in the system. It can also occur when components are plugged into different circuits in a house electrical system.

As already suggested, go through each component connection by connection and see determine which connection(s) is causing the problem. This is often the most difficult stage.


#8

Hi Elk,

thanks for your suggestion. I don’t know why my previous DAC does not have ground loop problem if there is any equipment having different ground voltage. does it mean DS is moe sensitive to grounding quality?


#9
bighead1707 said Hi Ted,

Glad to receive your reply:“It’s still grounded or you wouldn’t have a ground loop Typically everything is connected by interconnects, etc. which tie the grounds together.”

If everything is grounded together, why does my DS output ground noise? BTW, that noise comes out even I switch it off by switch at back but connect it to power bar. very strange. Without DS, my system is very quiet.


Howdy

Here is more detailed info than you might want/need, but learning how to deal with groundloops will serve most of us well: http://www.jensentransformers.com/an/ts_guide.pdf Remember Bill Whitlock is selling transformers to help with the problem, but his information is correct and useful, and he forgotten more than most of us will ever know about these things.

Jesnsen Transformers has a lot of other good info at http://www.jensentransformers.com/apps_wp.html

I suspect that whatever is your USB source is plugged into a different leg of your power than the rest of your audio system.

Still if lifting the ground connection on the DS fixes your problem, I’d just do that… There’s nothing inside the DS that could likely work loose or fail to cause this. The DS is probably working as designed.

-Ted


#10
bighead1707 said I don't know why my previous DAC does not have ground loop problem if there is any equipment having different ground voltage. does it mean DS is moe sensitive to grounding quality?
No. It just means it has a different circuit. There is an incredible amount of variables involved.

You will get it sorted out. It’s just a bother to get there.