[jeffyh]

I have a Topping NX1 and it's RF shielding is non-existent I think. I have it paired to my samsung galaxy s3 and the 4G radio is causing the issues. When I switch to 3G there is no perceptible interference.
 
Verizon frequencies:
   3G: 850/1900 MHz
   4G: 700 MHz, 850 MHz, 1700/2100 MHz
 
I did some basic research on RF shielding electronic components, but I'm a little confused. Has anyone ever done this before or could you provide some useful links as to how one would accomplish this?

 

[ClieOS]

  I have a Topping NX1 and it's RF shielding is non-existent I think. I have it paired to my samsung galaxy s3 and the 4G radio is causing the issues. When I switch to 3G there is no perceptible interference.
 
Verizon frequencies:
   3G: 850/1900 MHz
   4G: 700 MHz, 850 MHz, 1700/2100 MHz
 
I did some basic research on RF shielding electronic components, but I'm a little confused. Has anyone ever done this before or could you provide some useful links as to how one would accomplish this?

 
NX1 has a full metal case, so it already has all the RF shielding it should have. The problem lies in the headphone amp chip it uses, MAX9722, which is known to get easily affected by EMI.

 

[jeffyh]

   
NX1 has a full metal case, so it already has all the RF shielding it should have. The problem lies in the headphone amp chip it uses, MAX9722, which is known to get easily affected by EMI.

 
Confused... just read Wikipedia's EMI & EMI Filters and no longer sure where the root of the issue is then. What would need to be changed to eliminate the noise? Do I shield the amp IC?

 

[ClieOS]

   
Confused... just read Wikipedia's EMI & EMI Filters and no longer sure where the root of the issue is then. What would need to be changed to eliminate the noise? Do I shield the amp IC?

 
Shielding the chip will be very complex, as we are not just talking about putting extra metal around the chip, but probably also having some kind of low pass filter on power and sound input (not to mention those circuit will degrade SQ). By the time you are done with those, you could have bought another amp with less effort and money.

 

[cdsa35000]

By the look of it the casing is not grounded, the only ground contact point could come from the potmeter screw to the front plate.

But if the plate is painted and the pot housing is not soldered to the ground on the print, then you need to scrap of the paint around the pot and solder the pot housing to the ground points/common mass/earth on the print.

And front/back/holster plates screw together points are painted, so there no way they are grounded from the front plate.
You need to scrap off the paint around the contact points where all these plates are screwed together.
And the can also put grounded solder ring terminals to the screws, but there will be a gap between the plate (file off/drill the screw hole-corner to fit it gapless.
Measure with multimeter resistance if the whole casing is probably making contact/grounded with the print etc.



If still doesn't help, you can tape with copper shielding tape directly on both sides of the print, cover either the whole print (could cause overheating) or enough tape to cover with their blank legs and more over the amp ic and other signal processing ic's.
AND all the copper shielding needs to be grounded with solder grounded wires on the top of the copper tape.

http://www.amazon.com/Copper-Foil-Shielding-Tape-Guitars/dp/B00FV1MS0S

 

[wakibaki]

The cheapest form of shielding is separation, so keep the phone as far from the amp as possible. The pickup may not be radiated emissions anyway, it's more likely inductive if you have the devices in close proximity. Or just put the phone on 3G when you're using it for music.

 

[labrat]