LukeGTE Posted October 11, 2016 Share Posted October 11, 2016 Gadies and lentilmen! Some help please, if you would I have a P-Bass which buzzes like a mofo the more the tone pot is opened (turned clockwise). If I touch anything metal on the bass including the pot itself or the strings, the buzz goes until I take my hand away and it starts again. So I opened her up and saw the wiring was not accurate to any of the diagrams I could find online and there was solder everywhere. I detached everything and have rewired using the below diagram. But it still buzzed! I've tried with the earth wire from the bridge to either pot as well as from the shielding to either pot and all combinations. Still buzzing! The image shows the wiring minus any earthing. First time I've done something like this and I'm not sure what my next step should be. Anyone with experience, where should I look next? Quote Link to comment Share on other sites More sharing options...
gary mac Posted October 11, 2016 Share Posted October 11, 2016 Could well be a shielding problem. If the buzz goes away when you touch the strings etc. then the bridge earth is probably good. Make sure it's not something in the room, dimmer switches are notorious for this. Quote Link to comment Share on other sites More sharing options...
Grangur Posted October 11, 2016 Share Posted October 11, 2016 Looking at the picture, there doesn't seem to be an earth connection from the tone to the volume pot. I know, in theory at least, there is the connection of the metal of the screening, I also know that if the connection wasn't working the circuit wouldn't work at all as without that path there's no earth connection from the jack to the pup, but I wouldn't rely on that myself. I also agree with Gary Mac about the screening. Another point is the leg of the capacitor on the "hot" end is very close to the body of the tone pot. This can cause interference. It wouldn't do any harm to put a short length of shrink-sleeve on the leg of the capacitor for the same reason. Also, being picky, you could re-do the solder connections and make the bare, stripped wires shorter, so there's less chance of unwanted contact and interference. Sorry if this all seems picky, but it does all make it better. Quote Link to comment Share on other sites More sharing options...
LukeGTE Posted October 11, 2016 Author Share Posted October 11, 2016 [quote name='gary mac' timestamp='1476189926' post='3152101'] Could well be a shielding problem. If the buzz goes away when you touch the strings etc. then the bridge earth is probably good. Make sure it's not something in the room, dimmer switches are notorious for this. [/quote] [quote name='Grangur' timestamp='1476191486' post='3152131'] Looking at the picture, there doesn't seem to be an earth connection from the tone to the volume pot. I know, in theory at least, there is the connection of the metal of the screening, I also know that if the connection wasn't working the circuit wouldn't work at all as without that path there's no earth connection from the jack to the pup, but I wouldn't rely on that myself. I also agree with Gary Mac about the screening. Another point is the leg of the capacitor on the "hot" end is very close to the body of the tone pot. This can cause interference. It wouldn't do any harm to put a short length of shrink-sleeve on the leg of the capacitor for the same reason. Also, being picky, you could re-do the solder connections and make the bare, stripped wires shorter, so there's less chance of unwanted contact and interference. Sorry if this all seems picky, but it does all make it better. [/quote] Thanks for the speedy responses chaps. Really helpful. I'm sure people have asked similar questions before, good to know there's plenty of patient bass nerds out there! I've taken everything you said on board, have checked all possible sources of interference, trimmed and neatened the wires up before doing a rewire, wrapped the resistor in a bit of shrink sleeve. She's still humming away. Looks like I'm about to embark on my first cavity shielding job in the near future. Happy days Thanks again. Quote Link to comment Share on other sites More sharing options...
Grangur Posted October 11, 2016 Share Posted October 11, 2016 Hmmm... Is this your only bass? Do you have other basses which, when connected to the same amp set-up don't buzz? If you're not sure, take your bass down the road to a mate and try it. Otherwise, take it to a shop and "try an amp". See if it buzzes there. I have a Warwick Corvette that buzzes nicely every time the washing machine or microwave are being used. Quote Link to comment Share on other sites More sharing options...
LukeGTE Posted October 11, 2016 Author Share Posted October 11, 2016 [quote name='Grangur' timestamp='1476203599' post='3152297'] Hmmm... Is this your only bass? Do you have other basses which, when connected to the same amp set-up don't buzz? [/quote] I've got two others that don't buzz in the same amp but that's still a good idea. I'll take it to a shop Quote Link to comment Share on other sites More sharing options...
Grangur Posted October 11, 2016 Share Posted October 11, 2016 Yes, I'm just thinking you want to eliminate the chance that it's not the bass, but something else that's causing it. Screening won't hurt though. Quote Link to comment Share on other sites More sharing options...
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