I have an electric violin that was custom built. The Builder is in the UK and I'm in the United States so he cannot look at it. I've only had the violin for a few weeks, but I've noticed lately more noise. It seems like grounding noise. Some things I've found.
I hear the noise when:
Plugging 1/4" directly into an amp that is plugged in to the wall.
Plugging 1/4" directly into an amp that is battery powered
Plugging into my pedal board and then into the amp with both 1/4" and D.I. out
I DON'T hear the noise when:
Using my wireless system (Line 6 G50) to plug the instrument to the pedal board
If I touch the instrument AND something metal like on an pedal or the 1/4" plug the noise stops.
LINK to a video hearing the issue:
The maker suggested first try grounding to the metal casing of the volume knob and then if that didn't work, just remove the volume knob and go directly to the output jack. I don't have a ton of experience with this sort of thing so I might find an instrument tech to look at it.
Any ideas?
I hear the noise when:
Plugging 1/4" directly into an amp that is plugged in to the wall.
Plugging 1/4" directly into an amp that is battery powered
Plugging into my pedal board and then into the amp with both 1/4" and D.I. out
I DON'T hear the noise when:
Using my wireless system (Line 6 G50) to plug the instrument to the pedal board
If I touch the instrument AND something metal like on an pedal or the 1/4" plug the noise stops.
LINK to a video hearing the issue:
The maker suggested first try grounding to the metal casing of the volume knob and then if that didn't work, just remove the volume knob and go directly to the output jack. I don't have a ton of experience with this sort of thing so I might find an instrument tech to look at it.
Any ideas?
It does look like the wiring could be cleaned up, better wire terminations and grounding the pot case.
BUT the real clue is that the G50 is silent. What exactly are the other devices you are plugging into? Are they specifically acoustic instrument type devices with high input impedances?
EDIT: When you plug into the battery powered amp, is the whole signal chain unplugged from any wall socket?
BUT the real clue is that the G50 is silent. What exactly are the other devices you are plugging into? Are they specifically acoustic instrument type devices with high input impedances?
EDIT: When you plug into the battery powered amp, is the whole signal chain unplugged from any wall socket?
I would definitely try electrically connecting the metal case of the volume control to the
cable ground shield first. You can easily do this yourself. Just use a short piece of thin bare wire.
Ideally, only a little of the inner conductors would remain unshielded when connected to the volume control lugs.
cable ground shield first. You can easily do this yourself. Just use a short piece of thin bare wire.
Ideally, only a little of the inner conductors would remain unshielded when connected to the volume control lugs.
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@leadbelly Yes, when I was plugged into the battery-powered amp there was no connection to any wall outlet. I tried both plugging straight into the amp, and also powering my pedalboard with battery as well as the seperate battery amp. When I used the wireless G50 It did go through all of my pedals. I tried it going straight into the first pedal and then the same but with the wireless connecting to the first pedal. The pedals are powered by two Strymon Ojai which are supposed to create isolated power supplies. I'm not sure about the pedals. It looks like the pedals either have 1Mohm and a couple of them having 10Mohms which I believe is high input impedances. (Fishman Aura, Boomerang III Phrase Sampler, Digitech Drop, Zoom MS-50G, Baggs Align Reverb.)
@rayma The maker sent me this image. Is this what you are suggesting doing or is it something a bit different?
Thank you for you help.
@rayma The maker sent me this image. Is this what you are suggesting doing or is it something a bit different?
Thank you for you help.
Yes, but avoid cold solder joints. You don't need to use a thick wire from the case to the ground lug.
This is a high impedance connection area which easily picks up noise. Plus wood does not shield at all.
This is a high impedance connection area which easily picks up noise. Plus wood does not shield at all.
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@Arthur Jackson I have tried a few different cables.
@rayma Should I solder from the wire to the pot like in the photo or from the terminal to the pot (Or does it not matter which)? Also, I likely need to get a wire. Is there a specific gauge/material that I should get. All I have at the moment is some 22 AWG wire (I'm fairly new to this but have soldered some guirat cables in the past... although I'm not using any of those now).
Thank you
@rayma Should I solder from the wire to the pot like in the photo or from the terminal to the pot (Or does it not matter which)? Also, I likely need to get a wire. Is there a specific gauge/material that I should get. All I have at the moment is some 22 AWG wire (I'm fairly new to this but have soldered some guirat cables in the past... although I'm not using any of those now).
Thank you
From your picture of the pot, I would first scratch the surface of the pot so the solder sticks where you want it to. Then simply press the ground wire against the case and solder it in place, no additional wire required.
That is fine. Solder the wire to the pot case first, so you won't melt the cable insulation
when soldering the other end.
You cannot solder the cable shields directly to the pot case, since that would melt the cable.
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I was able to bend the cable enough to get it to touch the pot. I then soldered that in place after scuffing up the back of it. And... presto, hum is gone. I plan to contact someone to clean up my solder job and make sure it's secure.
Thank you everyone!
Thank you everyone!
