Members bob, just bob Posted January 27, 2008 Members Share Posted January 27, 2008 I put some stacked humbuckers into a j-bass today. The bridge sounds great, the neck hums (but otherwise sounds good). When I face my amp, it hums the loudest, when I turn 90 degrees, the hum largely goes away. Does this sound like a grounding issue? I want to assume I did something wrong, but this seems to act more like a single coil... so does it sound more like the lower coil isn't working? (Also, the p'ups had 2 wires.) Link to comment Share on other sites More sharing options...
Members jannda Posted January 27, 2008 Members Share Posted January 27, 2008 It may be a grounding Issue or a wiring and or shielding Issue or some of all three but my guess is probably Shielding but someone else might have a better Idea of whats up, but i'll bet it's shielding. Link to comment Share on other sites More sharing options...
Members 0175westwood29 Posted January 27, 2008 Members Share Posted January 27, 2008 is this just feedback? Link to comment Share on other sites More sharing options...
Members bob, just bob Posted January 28, 2008 Author Members Share Posted January 28, 2008 I thought shielding had a much greater impact on single coils. The hum does respond like SC hum though, which is why I thought the p'up might be bad. Link to comment Share on other sites More sharing options...
Members wades_keys Posted January 28, 2008 Members Share Posted January 28, 2008 That is odd. If you're feeling adventurous, you could always swap the bridge and the neck pickups around (see if the neck pup hums in the bridge position too). Link to comment Share on other sites More sharing options...
Members bob, just bob Posted January 29, 2008 Author Members Share Posted January 29, 2008 I tried wiring the pickup to ground other ways (I originally had both p'ups connected to a series/parellel switch), and I am getting the same result.... But to be clear, if it was a grounding issue, I would be getting a consistent amount of hum regardless of which direction I was facing? I want to rule out that I did something wrong before I blame the pickup... Link to comment Share on other sites More sharing options...
Members guitargod0dmw Posted January 29, 2008 Members Share Posted January 29, 2008 If it was a shielding issue, the hum would go away once you touch the bridge or the strings. Does it? Link to comment Share on other sites More sharing options...
Members Super Bass Posted January 29, 2008 Members Share Posted January 29, 2008 That is odd.If you're feeling adventurous, you could always swap the bridge and the neck pickups around (see if the neck pup hums in the bridge position too). Unless its a MIM Fender Jazz he won't be able to do that. Link to comment Share on other sites More sharing options...
Members bob, just bob Posted January 30, 2008 Author Members Share Posted January 30, 2008 No, the hum doesn't go away when I touch the strings or bridge. Link to comment Share on other sites More sharing options...
Members guitargod0dmw Posted January 30, 2008 Members Share Posted January 30, 2008 Are you positive that it's all wired correctly? Link to comment Share on other sites More sharing options...
Members bob, just bob Posted January 30, 2008 Author Members Share Posted January 30, 2008 I'm pretty certain that everything is wired correctly. The pups were not the 4-wire style - they just had a hot lead and a ground (the new ones were Fender pickups). I installed a switch so it would go from stock j-bass to pups in series at the same time I put the new pups in. This is where the bridge worked fine and the neck had hum. I disconnected the neck's ground wire from the switch and wired it directly to ground. This didn't fix the problem. I am somewhat new to diy tinkerings like this, but I didn't see any bad solder joints during the process. I have a rehearsal this weekend and an audition coming up, and I needed a working bass, so I put the old pickups back in last night and they are working just fine - no weird noise... So I don't think there is anything wrong with the switch. But the single coil hum from the old pickups responded in a very similar manner and sounded similar to the hum from the "noiseless" pickup. Link to comment Share on other sites More sharing options...
Members Super Bass Posted January 30, 2008 Members Share Posted January 30, 2008 Are they Fender Noiseless pickups? I've heard that they're actually noisy... Link to comment Share on other sites More sharing options...
Members bob, just bob Posted January 31, 2008 Author Members Share Posted January 31, 2008 Are they Fender Noiseless pickups? I've heard that they're actually noisy... I tried the Fender scns after getting a thing for 20% off at musicians friend. The bridge was very quiet... it was just the neck I had a problem with.... Link to comment Share on other sites More sharing options...
Members FebruaryStars Posted January 31, 2008 Members Share Posted January 31, 2008 It sounds like a wiring issue or just normal generated feedback. Lighting can often effect feedback levels a lot. Check this out it shows the switch as a push pull but it's the same with a normal DPDT switch. Which is what you should be using for a series/parallel switch. If it looks correct and still hums go point to point and check each solder... If that doesn't help it could be the pickup or just normal hum from a hot pickup. Hope I've been of some help. Just an FYI: Shielding doesn't reduce the normal feedback from being in an electrical field or from high gain... it only quiets the 60 cycle hum you get from letting go of the strings. Nothing less, nothing more. Link to comment Share on other sites More sharing options...
Members basste Posted January 31, 2008 Members Share Posted January 31, 2008 Have you correctly isolated cavities ? (with copper tape) that could help. You can try to switch the bridge one with the neck one, just solder at the bridge place, and solder the bridge pickup to the nexk place. You will see if it comes from your shielding or your pickup... If it's the pickup, perhaps the two magnet part aren't assembled in opposition polarity inside the pickup (it's kind of humbucker IIUW ?) So, you can't do anything that claim for a change. Link to comment Share on other sites More sharing options...
Members Super Bass Posted January 31, 2008 Members Share Posted January 31, 2008 Have you correctly isolated cavities ? (with copper tape) that could help. Its very easy to do and takes maybe an hour max if you're careful. Here's one I did earlier Link to comment Share on other sites More sharing options...
Members bob, just bob Posted February 1, 2008 Author Members Share Posted February 1, 2008 FebruaryStars, that is basically what I did except with a toggle switch instead of a push/pull pot. I did notice something in that diagram though that I feel rather dumb about... My stock J bass didn't have a wire from the back of the pot to the sleeve of the jack (ok, so I'm a noob...). I'll connect that and see how that goes. Also, where can I get the copper tape? Just a regular hardware store? Link to comment Share on other sites More sharing options...
Members Super Bass Posted February 1, 2008 Members Share Posted February 1, 2008 I bought mine from http://www.stewmac.com but I guess you could probably find it in a hardware store too. Link to comment Share on other sites More sharing options...
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