Ground or shielding issue? And where?

B

Bihari Botond

Aug 21, 2018
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#1
Hi. I've got 3 basses. 2 of the Musicman Stingray 3 eq and one Fender dimension USA bass . Yesterday I was trying record some groove when I noticed that there is an electric noise in the recorded track. I started to investigate, where the noise coming from. If I touched any of the pots, jack plug or the the audio interface itself, the noise disappeared. I also unplugged the main extension cord from the main socket so there was nothing plugged in, and only used the battery of my laptop which can supply the audio interface so I can still make a record, the noise disappeared again.
Also there are some differences between the basses. If I touch the older stingray strings, bridge, keys the noise still there and if touch the pickup pole pieces the noise even bigger. Only the jack plug and the pot knobs kill the noise.
As I remember with the newer Stingray and the Fender happend the same thing plus if I touch the strings the noise also disappeared. Also they have less noise than the older stingray.
I tried 3 different instrument cable, and tried with an amp, the problem is still there.
I hope I described well my problem, if not please let me know what should I check if i skipped it . I would really appreciate your time and help. Thanks
 
#2
Your laptop on battery removes the noise?

if that the case I suspect whatever AC source your bass amp or effects are plugged into are not the same AC circuit your laptop is plugged into.

Let’s say your laptop is plugged into an interior wall that has a room on the other side and your bass peripherals are plugged into an outside wall with the world on the other side. Very good possibility that those outlets are not on the same AC circuit. Especially in an old building.

This is an important thing playing live as well. Plug your amp into the same circuit as your peripherals. You need to have the exact same power line or you can have AC phasing issues.
 
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#3
96tbird said:
Your laptop on battery removes the noise?

if that the case I suspect whatever AC source your bass amp or effects are plugged into are not the same AC circuit your laptop is plugged into.
Click to expand...
That's not the case. If I unplug the laptop power cord, it will use only the battery. Everything is on the same wall socket in this room, using power extension cords.
 
#5
Yes the noise disappeared when I unplugged everything and used only the battery. As I said, the room fitted with only one wall socket which is wired towards with power extension cords.
 
#6
I suspect the plug socket is your issue. The last house I rented wreaked havoc on my audio interface/studio computer. One socket introduced white noise into everything, while another introduced grounding issues on my basses that never occurred before. I purchased a house last year, had electricians check everything before we moved in, and all of the same equipment is now dead silent.
 
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#7
Ok so AC doesn't seem to be the problem. You have an RF problem which could be the power adapters for your laptop, and any effects you are running OR the bass itself. All can pick up radio frequencies.

Do you have fluorescent lighting near any components or powered on the same circuit?
 
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#8
Lownote38 said:
I suspect the plug socket is your issue. The last house I rented wreaked havoc on my audio interface/studio computer. One socket introduced white noise into everything, while another introduced grounding issues on my basses that never occurred before. I purchased a house last year, had electricians check everything before we moved in, and all of the same equipment is now dead silent.
Click to expand...
This too....
 
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#9
96tbird said:
Ok so AC doesn't seem to be the problem. You have an RF problem which could be the power adapters for your laptop, and any effects you are running OR the bass itself. All can pick up radio frequencies.

Do you have fluorescent lighting near any components or powered on the same circuit?
Click to expand...

A dimmer switch on the same circuit can cause problems as well. Not the new ones made for LED lighting, but the older ones. When they are set any way other than full on, or full off, they introduced buzzing into audio equipment.
 
#11
That using battery power removes the noise is a clear indicator that the source is your AC power. You may also have less than ideal shielding and or grounding on your basses but first you have a noisy power source.
 
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