bassituation Posted February 24, 2015 Share Posted February 24, 2015 Hi, I've installed a new set of Wilkinson Alnico pickups into an old japanese 70s jazz bass. I've matched how the old ones were wired, but it's not a schematic I've seen on the web and now I've got a faint hum/hiss a bit like static. When I touch any metal part of the bass it goes. The ground to the bridge is fine and connects to the jack. As you will see, with the old pickups both pickup grounds (black) were soldered to the back of the bridge pot, so I just did the same. Any advice appreciated. Cheers Martin Quote Link to comment Share on other sites More sharing options...
scojack Posted February 24, 2015 Share Posted February 24, 2015 (edited) I can only see a ground on the jack - bridge. You could/should maybe ground the back of all the pots and make sure they all have a path to the ground on the jack. PS You could also add some copper tape (or shielding paint) to the cavities and ground it too this might help to eliminate any hum. Edited February 24, 2015 by scojack Quote Link to comment Share on other sites More sharing options...
bassituation Posted February 24, 2015 Author Share Posted February 24, 2015 Yeah, that's a good shout and what I've seen in diagrams, thanks. Funny how the old pickups were fine without that? Quote Link to comment Share on other sites More sharing options...
Rumple Posted February 25, 2015 Share Posted February 25, 2015 I'm no expert but I'm quite surprised that the original wiring didn't hum due to the lack of earthing. Quote Link to comment Share on other sites More sharing options...
KiOgon Posted February 25, 2015 Share Posted February 25, 2015 Many Jazz bass wiring relies on the mechanical connection between the mounting of pots & jack socket onto the metal bell plate, it saves .02 pence worth of extra wire but of course as soon as you get a loose nut or even a bit of corrosion under your nuts any earthing is at best - intermittent & doubtful It appears from your photo' that the pots are not of the 'highest quality' & also they are 500K Linear, which is certainly not what I would recommend for a Jazz Bass they are probably at the end of their useful life anyway! I would suggest a new wiring kit would go a long way to solving all your problems Quote Link to comment Share on other sites More sharing options...
bassituation Posted February 25, 2015 Author Share Posted February 25, 2015 Thanks for your comments, I thought I could slip in some new pickups without problems, but have now decided to go the whole works and do full shielding and new electronics. I will report back, fingers crossed. Quote Link to comment Share on other sites More sharing options...
paul_5 Posted February 25, 2015 Share Posted February 25, 2015 [quote name='KiOgon' timestamp='1424859333' post='2701162'] I would suggest a new wiring kit would go a long way to solving all your problems [/quote] If only there was somewhere BC'ers could get a handmade, solderless, high quality replacement bell plate with everything already attached that would just drop in to the existing cavity... eh Kiogon? Seriously though, the 500k linear pots should ideally be 250k logarithmic for passive single coil pickups. 500ks will deliver more top end to the output jack, so this might account for the increased hiss that you're experiencing. Whilst you've got it in bits I'd recommend shielding the cavities too (including pickup routes as well) as the single coils don't reject extraneous noise (mains interference, emf etc...) as well as humbucking pickups do. If you're desperate then glue and tinfoil would do it, but I picked up some self adhesive metal foil for doing flashing on roof tiles or something similar. Works a treat. Quote Link to comment Share on other sites More sharing options...
bassituation Posted February 27, 2015 Author Share Posted February 27, 2015 UPDATE: The pots came today. I did the sheilding yesterday to both pickup cavities and electronics and ground wires into the electronics. I got everything soldered and back together about an hour ago......and..... silence is golden. It now sounds superb, no hiss, hum or audible irritations. Well happy. Cheers all. Quote Link to comment Share on other sites More sharing options...
Rumple Posted February 28, 2015 Share Posted February 28, 2015 Excellent Quote Link to comment Share on other sites More sharing options...
Conan Posted February 25, 2016 Share Posted February 25, 2016 Where is the best place to buy shielding/conductive paint in small quantities? The sources I've located so far seem very expensive - but maybe I'm looking at the wrong stuff? What is the correct name, as there appear to be several? Like the example above, I am hoping to remedy a significant earth buzz on a Jazz bass. Quote Link to comment Share on other sites More sharing options...
rmcki Posted March 1, 2016 Share Posted March 1, 2016 [quote name='Conan' timestamp='1456423163' post='2988923'] Where is the best place to buy shielding/conductive paint in small quantities? The sources I've located so far seem very expensive - but maybe I'm looking at the wrong stuff? What is the correct name, as there appear to be several? Like the example above, I am hoping to remedy a significant earth buzz on a Jazz bass. [/quote] As recommended by Chris at Overwater [url="http://uk.rs-online.com/web/p/shielding-aerosols/7259987/"]http://uk.rs-online.com/web/p/shielding-aerosols/7259987/[/url] Quote Link to comment Share on other sites More sharing options...
bassituation Posted March 1, 2016 Author Share Posted March 1, 2016 Is there a reason to use paint? I used tape and it was cheap and relatively easy to apply. Worked a treat. Quote Link to comment Share on other sites More sharing options...
Norris Posted March 1, 2016 Share Posted March 1, 2016 I used this http://www.catmusic99.co.uk/product/shielding_paint Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted March 2, 2016 Share Posted March 2, 2016 [quote name='KiOgon' timestamp='1424859333' post='2701162'] Many Jazz bass wiring relies on the mechanical connection between the mounting of pots & jack socket onto the metal bell plate, it saves .02 pence worth of extra wire but of course as soon as you get a loose nut or even a bit of corrosion under your nuts any earthing is at best - intermittent & doubtful It appears from your photo' that the pots are not of the 'highest quality' & also they are 500K Linear, which is certainly not what I would recommend for a Jazz Bass they are probably at the end of their useful life anyway! I would suggest a new wiring kit would go a long way to solving all your problems [/quote]Without knowing the maker, you cannot just assume that B is linear. In Britain and many other places A is linear and B is Log. I will give you that most countries now follow the US convention of A - Audio ( logarithmic ), B Linear but you can't just assume one or other convention. Quote Link to comment Share on other sites More sharing options...
tom1946 Posted March 8, 2016 Share Posted March 8, 2016 [quote name='KiOgon' timestamp='1424859333' post='2701162'] Many Jazz bass wiring relies on the mechanical connection between the mounting of pots & jack socket onto the metal bell plate, it saves .02 pence worth of extra wire but of course as soon as you get a loose nut or even a bit of corrosion under your nuts any earthing is at best - intermittent & doubtful It appears from your photo' that the pots are not of the 'highest quality' & also they are 500K Linear, which is certainly not what I would recommend for a Jazz Bass they are probably at the end of their useful life anyway! I would suggest a new wiring kit would go a long way to solving all your problems [/quote] Absolutely agree, this man makes the best quality wiring kits. Any bass I've owned and fitted one to has been perfect. Quote Link to comment Share on other sites More sharing options...
TrevorR Posted March 9, 2016 Share Posted March 9, 2016 [quote name='rmcki' timestamp='1456830694' post='2992570'] As recommended by Chris at Overwater [url="http://uk.rs-online.com/web/p/shielding-aerosols/7259987/"]http://uk.rs-online.com/web/p/shielding-aerosols/7259987/[/url] [/quote] This Scotts Bass Lessons vid has him chatting about it about 6 mins in and why to use the metal paint not the graphite stuff... http://youtu.be/czK3IjnM_oE Quote Link to comment Share on other sites More sharing options...
.gif.9ad672bb8b84505709f76b39c8c256ec.gif)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.