grounding issues

[Anouk]

Hello, I have a new amp and a new pair of headphones, I get a hum at times and it disappears when i touch the volume pot of the amp, I also get random noises which should not be there. I am using my amp, a woo wa2 with a laptop and my ibasso d10 as dac. The dac is connected to the laptop via usb with a kimber usb cab le. I have tried using the laptop and dac with battery power but the random noise and the him do remain. I know that this is not an amp failure.
I supspect there are grounding issues and hope a new cable will fix this but i am not sure if the wall receptable sI am using for my laptop and woo are grounded, also I know that the laptops pwoer adaptor is rather noisy to begin with.
Is there anything I can do about this to fix my hum and noise issues?
Thanks in advance
Greetings, Anouk,

 

[CDBacklash]

It could be the result of a poor grounding scheme. Personally, my LDMKIII came with an awful ground loop and adjusting one of the screws was responsible for fixing the sound (it probably came out of contact with the grounding scheme).
Alternatively, I believe you can remove the ground pin from your power cable.
Before someone else asks, can we get pics of the internals (not that I can do much with it).

 

[Anouk]

Hello, no, sorry I cant igve you pictures of the internals of the woo amp. I really hope a new power cord and new tube will fix things though because it is very irritating. I still find it very strange that i have these problems with the jvc while with th epro900 I only heard a VERY minor hum. If tubes and a power cord wont fix it I will try the akg k701 because I think that headphone has a sensitivity of 95 db also much like the pro900.
Greetings, Anouk,

 

[Michgelsen]

Another tube or headphone will not fix a ground loop. A new power cord could, if it isn't grounded and the old one was, for example.
Do you have a lot of equipment connected to each other? You could try to unplug everything and then slowly put your system back together. You can then find out from which connection the ground loop is originating.
It's most likely that there is a circle for electricity to follow somewhere in your system.

 

[Anouk]

Hello, Well I think there might be a tube AND a ground loop problem because with my dx1000 I get two kinds of hum and random noises (one kind of hum gets only irritating with very loud volumes). I am pretty sure the ground loop issue is coming from the amp. The amp is only connected to my d10 dac and the jvc and I have tried the amp briefly with no source. The amp and my laptop are both connected to separate wall connectors. I have tried my d10 and my laptop on battery mode and the hum is still there.
I am not sure if my current cord is grounded or not, i bought it at the local computer store.
Greetings, Anouk,

 

[CDBacklash]

You can tell if the current cord is grounded by pulling it out and seeing if it has three pins at the male end. (and if the part you plug it into on the amp has three also).

 

[Anouk]

Hi, well I wanted to get a better power cable for the amp anyway. I just hope it will be fixed soon or I will have to get a les ssensitive headphone because I did not have these problems with the pro900.
Greetings, Anouk,

 

[Michgelsen]

It can be very hard to fix a ground loop and I'm no expert either, but you should try to minimize the number of loops and if not possible the area of the loop (so I read here).
You said that the hum disappears when you touch the volume pot. It could be that you form a different loop in that case, connecting the cases of two devices together. You could do that with a piece of wire too.

 

[Michgelsen]

Quote:

Originally Posted by CDBacklash /img/forum/go_quote.gif You can tell if the current cord is grounded by pulling it out and seeing if it has three pins at the male end. (and if the part you plug it into on the amp has three also).

Dutch power cables do not have three pins when grounded, they look like this, and fit in this.

Edit: sorry for double post, I thought I was editing but apparently was making a new post.

 

[Anouk]

Wow, apparently I am not the only one having hum problems with second hand woo amps:
http://www.head-fi.org/forums/f5/jus...d-help-432641/
Thanks for that link Blackmore, it is really the seem problem i have, the low level, lower frequency hum gets louder with louder volume, i also have random noise and static although its not real loud. static is in my left ear. I am still holding out hope that changing tubes and pwoer cord will fix something and a different headphone of course.
Greetings, Anouk,

 

[earwicker7]

Quote:

Originally Posted by Anouk /img/forum/go_quote.gif Wow, apparently I am not the only one having hum problems with second hand woo amps: http://www.head-fi.org/forums/f5/jus...d-help-432641/ Thanks for that link Blackmore, it is really the seem problem i have, the low level, lower frequency hum gets louder with louder volume, i also have random noise and static although its not real loud. static is in my left ear. I am still holding out hope that changing tubes and pwoer cord will fix something and a different headphone of course. Greetings, Anouk,

The random noise is more than likely electronic interference of some sort from radio waves, cellphone towers, etc.. I had a problem with this type of noise at my old place (it doesn't happen where I'm currently living). The only thing that solved it was adding a Shunyata power cord that has an RFI/EMI "absorbing" powder in it to my CD player (it was never a problem with my analog setup... apparently digital circuits are very sensitive to this type of interference).

 

[Anouk]

Hello, well the thing is i dont have these random noises if I use my ibasso d10 as headphone amp (in the woo setup it is functioning as the dac via aux).
I am ordering a new power cord for the woo and that is shielded so I hope this will fix it.
Greetings, Anouk,

 

[earwicker7]

Quote:

Originally Posted by Anouk /img/forum/go_quote.gif Hello, well the thing is i dont have these random noises if I use my ibasso d10 as headphone amp (in the woo setup it is functioning as the dac via aux). I am ordering a new power cord for the woo and that is shielded so I hope this will fix it. Greetings, Anouk,

Different pieces of equipment will react to interference in different ways, so it could be that the Woo is really sensitive.