My project parts P Bass has an annoying buzz when I have the tone knob turned up past about 50%. It stops when I touch the strings, so from reading on Talkbass I decided to try shielding tape. I did the cavity and the back of the pickguard, doesn’t seem to have helped. Any ideas what I did wrong? Not an electronics genius by any means. Could changing the tone pot cure it? Thanks
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P Bass still has buzz after shielding it
- Thread starter Dan1985
- Start date
At first glance I see potential continuity gap around where that wire (bridge ground?) pops out. Better to make a hole in the foil where it pops out of the body.
Did you also shield the pickup cavity and ground the shielding?
I did mine and it is very quiet now. I followed this video
I did mine and it is very quiet now. I followed this video
I didn’t ground the shielding. I was under the impression the shielding adhesive did that. But I’m clueless. Thanks for the video recommendation.
It looks to me that you have the wire to the pickups connected properly, but are you certain the ground wire between the frame of the pots to the bridge is making a solid connection? That would account for the buzzing you're encountering.
Here is what I do now to avoid such problems.
First, I use a small wire to ground the pickups cavity (ies) and the bridge :
First, I use a small wire to ground the pickups cavity (ies) and the bridge :
Yes, I am pretty sure it has a good ground connection. Checked it under the bridge and the casing on pots. And buzz goes away when I touch the bridge, strings, or knobs. Or when I face the guitar in certain directions, even.
Then, I connect those 3 or 2 wires together in the control cavity, I then use another wire to this ground post to ground the jack negative :
I also make sure my control plates, pickguard and rear cavity plates are fully grounded by applying a layer of aluminum or copper foil.
Inside the cavities, I usually prefer using some conductive paint. Usually, two layers are enough but I always validate with my multimeter until it beeps.
I also make sure my control plates, pickguard and rear cavity plates are fully grounded by applying a layer of aluminum or copper foil.
Inside the cavities, I usually prefer using some conductive paint. Usually, two layers are enough but I always validate with my multimeter until it beeps.
What model P bass has the large cover on back? Custom built? Thanks for your ideas.Then, I connect those 3 or 2 wires together in the control cavity, I then use another wire to this ground post to ground the jack negative :
I also make sure my control plates, pickguard and rear cavity plates are fully grounded by applying a layer of aluminum or copper foil.
Inside the cavities, I usually prefer using some conductive paint. Usually, two layers are enough but I always validate with my multimeter until it beeps.
I have a bass that had the same problem – hum that quieted when I touched the strings. Talkbass research told me the problem was a bad ground between the electronics and bridge. My bridge was painted black. So I sanded down the backside to bare metal where the ground wire touched it. Put it all back together, and the problem was gone.
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Make sure that you have only one route to ground for everything - i.e. pickup, pots and shielding (star grounding connected to the ground tab on your output jack). More than one ground route can create a ground loop/buzz.
When you touch the strings you are partially shielding the PUs by proximity alone.
Mounting the pots should ground the cavity tape.
There appears to be no connection to earth the pickguard to the cavity. There needs to be an overlap.
That said, single wires to the PU may be traditional but the secure way is to use 4 core coaxially-shielded cable, like most modern PUs are now suppled. The sound is the same but much quieter, and convenient if you want to coil tap series/parallel etc.
I also replaced live wires between pots and socket with small shielded cable.
Cable shielding is more complete and permanent than cavity shielding IMO.
It's how your guitar cable works, and I simply kept the same tight continuity right through to the PU. You should notice an improvement with this modernisation.
I sometimes worked in theatreland and had to compete with all sorts of dimmers, transformers et al. Rather than switch to an active bass I tracked down every chink in my shielding armour.
In addition to the earthed plates beneath the PUs, I also cut brass strips to surround the coils, and plates to top them with holes punched for the poles. These were earted and mounted under the covers.
I call this 'wrap shielding' and it was a very careful labour of love. The result was the cleanest signal/noise output I've ever had, and that also allowed me extra EQ for a clear prominent tone. It showed up any crap playing rather well.
Mounting the pots should ground the cavity tape.
There appears to be no connection to earth the pickguard to the cavity. There needs to be an overlap.
That said, single wires to the PU may be traditional but the secure way is to use 4 core coaxially-shielded cable, like most modern PUs are now suppled. The sound is the same but much quieter, and convenient if you want to coil tap series/parallel etc.
I also replaced live wires between pots and socket with small shielded cable.
Cable shielding is more complete and permanent than cavity shielding IMO.
It's how your guitar cable works, and I simply kept the same tight continuity right through to the PU. You should notice an improvement with this modernisation.
I sometimes worked in theatreland and had to compete with all sorts of dimmers, transformers et al. Rather than switch to an active bass I tracked down every chink in my shielding armour.
In addition to the earthed plates beneath the PUs, I also cut brass strips to surround the coils, and plates to top them with holes punched for the poles. These were earted and mounted under the covers.
I call this 'wrap shielding' and it was a very careful labour of love. The result was the cleanest signal/noise output I've ever had, and that also allowed me extra EQ for a clear prominent tone. It showed up any crap playing rather well.
I'm happy to be corrected however it is my understanding.....
that if noise increases when you touch the strings (or other metal) it's a grounding issue.....
If the noise decreases when you touch the strings it's an RF issue and can be decreased with good shielding.
you have to ground ALL the shielding to the ground on the jack or it will do nothing to help with noise.
A grounding problem in any part of the signal chain can cause this type of issue.
If you can, and have not done it yet, try a different bass with the same amp, cable, and power outlet to make sure the bass is the problem.
If you can, and have not done it yet, try a different bass with the same amp, cable, and power outlet to make sure the bass is the problem.
You mentioned you didn’t ground the foil. Solder a wire to the foil and solder that wire to the input jack ground or to the pot where your other ground wires connect. The foil tape has to be wired to ground. That’s likely the issue, do that first before sanding bridges or anything else.