So, my office/music room is a converted garage. A lot of the electrical in here was done by the former owner who had to sell because of substance abuse problems (I know this because my folks live right next door, and the former owner was a family friend). I’ve discovered that the electrical in here has some grounding issues and there is a lot of 60 cycle interference floating around. I’ve gone through a lot of frustration with several different basses and amps to determine that.
That said, I am fairly convinced that my new Dimension has a shielding problem. There is an electrical buzz happening when I’m not touching the strings, which is not 60 cycle related, nor is it faulty-ground-electrical related as it happens in other rooms on other circuits on other amps, where my other basses do not have that problem.
I just cracked it open, and the shielding is… minimal. Here’s a pic:
As you can see, the pickguard is only shielded directly around the knobs and preamp, and the electronics cavity is only shielded with shielding paint on the bottom. I have not yet gotten into the pickup cavity, there’s something sticky holding it in that I don’t want to rip up until I do a bit more research on what it is.
Help me, experts. I have copper shielding tape… should I lay that down to cover the electronics cavity completely? I have a soldering iron, but I’m not good at soldering, but I am good at putting tape down around existing holes so I should be able to put the tape down without having to undo anything.
Also, what about the back of the pickguard?
Finally, should the tape be somehow soldered to ground?
That black paint in the cavity is shielding paint. You can shield all day but if it’s something else it won’t matter.
Start with the bridge which is usually the big suspect, then make sure no little connections inside are touching or loose. I have basses with zero him and no shielding and some with loads oh shielding and hum.
Any time I see a circuit board I assume there will be some noise, it’s not silent generally ever.
All that said adding shielding everywhere never hurts.
You might also try some ally foil fashioned into the shape of a helmet
That paint seems so expensive @John_E but must be the bees knees as many of the high end manufacturers use it . I do have some in my eBay watch list
Shielding paint is not that expensive pet use but the initial buy in is definitely more. I painted 3 basses double layers each and it still looks full. I’m sure I can cover more basses than copper tape at the same cost and much less wasted not overlapping. That said if you only have to do one bass, it makes no sense to get one.
If it doesn’t hum until you touch the strings that means that your bridge is not grounded correctly.
If it hums but stops when you touch the strings that means that your bridge is grounded correctly but you have a shielding issue.
Looking at your pic, I see that you have black paint on the bottom of the cavity. Even if it’s conductive paint it seems to be only decorative because for shielding to work it must be grounded.
If I were you I’d bust out the copper tape and do the whole cavity and a larger area of the pickguard, making sure the the tape on the pickguard will contact the cavity tape when it’s installed. Run a ground to the shielding and you should be good. If you still have hum it could be that your pickup wire is unshielded or that there is a problem with the circuit board itself.
As expensive as you may think Stewmac is most other ones are even more expensive. I was even looked in to the aerosol spray version but then I stopped myself if I have to tape up each use it’s a big hassle.