solo4652 Posted April 1, 2016 Share Posted April 1, 2016 Folks, My Yamaha BB424 is a cracking bass for the money - it's taken over from my BB1200 and my Fender P as my main bass. However, it's humming a lot. In the same room, same equipment, both the BB1200 and the Fender P are silent. The hum from the BB424 seems to be from an external source - as I move round the room and turn round, the hum can increase dramatically. Will shielding the cavity cure this? Quote Link to comment Share on other sites More sharing options...
Twincam Posted April 1, 2016 Share Posted April 1, 2016 (edited) Considering it changes as you walk round the room it would suggest a bass shielding issue. Also check the bass ground wiring. Edited April 1, 2016 by Twincam Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted April 1, 2016 Share Posted April 1, 2016 Yep! Shield the bass and don't forget to connect the ground to the shielding so it's also grounded properly. Problem solved! Quote Link to comment Share on other sites More sharing options...
solo4652 Posted April 2, 2016 Author Share Posted April 2, 2016 Thanks folks. I'll paint the cavities with two coats of conductive paint. No pickguard to worry about. Pardon my ignorance, but could you please clarify "check bass ground wiring" and "connect the ground to the shielding"? I'm not the world's best DIY'er... Quote Link to comment Share on other sites More sharing options...
Norris Posted April 2, 2016 Share Posted April 2, 2016 I think that means to check the continuity of the connection between the bridge, the cavity shielding and the outer sleeve of the jack socket. There should be a wire that makes contact under the bridge - if the humming stops when you touch the bridge that's a sign of a dodgy connection Quote Link to comment Share on other sites More sharing options...
solo4652 Posted April 2, 2016 Author Share Posted April 2, 2016 (edited) Bit more info: Switched to P pickup = virtually no hum, both pickups = more hum, J pickup = most hum. Hum does not diminish if I touch the bridge. So - shall I just shield around the J pickup? I've just lifted the J pickup out. Cavity is painted black. There is a wire screwed to the floor of the cavity. The bare wire then exits the cavity through a side wall. Is this the ground wire? How about I unscrew the wire, line the cavity with some copper tape I have here and then screw the wire back in place with the screw going through the copper tape? Any good? [attachment=216015:100_0872.JPG] Edited April 2, 2016 by solo4652 Quote Link to comment Share on other sites More sharing options...
solo4652 Posted April 2, 2016 Author Share Posted April 2, 2016 Errrm, I've lined the J cavity with copper tape, overlapping the top edges under the pickup surround. I screwed the earth wire back into place through the tape. I removed the bridge and made sure there was a good fan of bare wire under it. Hasn't made any difference to the humming. On the plus side, I haven't made it any worse which, for me, is a result in itself... Quote Link to comment Share on other sites More sharing options...
gary mac Posted April 2, 2016 Share Posted April 2, 2016 Do you own a multi-meter? If so, you should use it to check continuity. Not all copper tapes are right for shielding/screening. Quote Link to comment Share on other sites More sharing options...
solo4652 Posted April 2, 2016 Author Share Posted April 2, 2016 (edited) A multi-meter!? Not sure what one of those is, being honest. Edited April 3, 2016 by solo4652 Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted April 5, 2016 Share Posted April 5, 2016 When using copper tape you should use one with conductive glue or you'll need to drop a bit of solder to join every piece together in continuity. Spraying with conductive paint is a good solution but you need at least 2 or 3 coats to have a funcitional end coat and even doing that paint isn't as good shield as copper, is more suitable for grounding. Having said that, i had a buzz on a Ken Smith i used to own, opened the control plate and saw that the conductive paind had sunk in the wood during it's lifetime. After checking with Ken himself i sprayed 3 new coats of graphite spray and added a new wire from the electrics ground screwed on the wood through the paint. Problem solved! Reading the OP's last post regarding the hum comming from the bridge pickup - this is completely normal as the P pickup is humbucker, so hum-canceling, and the J is single coil. That doesn't mean that the J pickup is knackered or there's a fault in the electronics, the J is more prone to show earth/rf problems. I would strat by shielding/grounding the entire bass before taking the soldering iron to the electrics. Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted April 5, 2016 Share Posted April 5, 2016 [quote name='solo4652' timestamp='1459634524' post='3018318'] A multi-meter!? Not sure what one of those is, being honest. [/quote] Quote Link to comment Share on other sites More sharing options...
solo4652 Posted April 6, 2016 Author Share Posted April 6, 2016 Well, yes - I can do a Google image search to see what one looks like. However... Quote Link to comment Share on other sites More sharing options...
Norris Posted April 7, 2016 Share Posted April 7, 2016 A multimeter can measure various things in electrical circuits, one of which being continuity i.e. can electricity flow between the two points where you place the probes Quote Link to comment Share on other sites More sharing options...
Guest MoJo Posted April 7, 2016 Share Posted April 7, 2016 [quote name='solo4652' timestamp='1459597537' post='3017932'] Bit more info: Switched to P pickup = virtually no hum, both pickups = more hum, J pickup = most hum. Hum does not diminish if I touch the bridge. So - shall I just shield around the J pickup? [attachment=216015:100_0872.JPG] [/quote] Exactly the same as my BB414. The bridge pickup is single coil and will pick up interference from dimmer circuits etc. The neck pick-up is humbucking just like a P-bass so doesn't suffer in the same way. Not a lot more you can do about it other than shielding Quote Link to comment Share on other sites More sharing options...
Truckstop Posted April 7, 2016 Share Posted April 7, 2016 My BB424 has a very slight him when J pup is solo'd (as to be expected). Mind you, it is slight and I don't notice it unless I really listen for it. Is it an unbearable noise when you have yours solo'd? Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted April 7, 2016 Share Posted April 7, 2016 [quote name='solo4652' timestamp='1459968891' post='3021416'] Well, yes - I can do a Google image search to see what one looks like. However... [/quote] You just made my point. If you need to google for a image of a multimeter then i strongly advise you to take the bass to a tech. Soldering and taking multimeter readings on a bass wiring isn't something that can be explained in a post. You need to read through a lot of threads to gather as much information as you can and then practice a bit in old knackered PCB's before you risk doing more damage than good to your bass. Now, if you did recognised the multimeter or even had one of those around the house, i could tell you to turn it on in the "ohms" setting and check continuity over your wiring. You would need to be aware of how the pots and cap influence the readings to check if everything is fine. Again, you should really start by shielding the entire bass with copper tape with conductive glue. Then, if the hum continues, look at other options. We're here to help, and even though sometimes i enjoy a good laugh/joke, i posted the pic to help you, not to make fun of you. Quote Link to comment Share on other sites More sharing options...
EvilSmile Posted April 7, 2016 Share Posted April 7, 2016 [quote name='Ghost_Bass' timestamp='1459872944' post='3020470'] Reading the OP's last post regarding the hum comming from the bridge pickup - this is completely normal as the P pickup is humbucker, so hum-canceling, and the J is single coil. [/quote] [quote name='MoJo' timestamp='1460021863' post='3021807'] Exactly the same as my BB414. The bridge pickup is single coil and will pick up interference from dimmer circuits etc. The neck pick-up is humbucking just like a P-bass so doesn't suffer in the same way. Not a lot more you can do about it other than shielding [/quote] [quote name='Truckstop' timestamp='1460022159' post='3021813'] My BB424 has a very slight him when J pup is solo'd (as to be expected). Mind you, it is slight and I don't notice it unless I really listen for it. Is it an unbearable noise when you have yours solo'd? [/quote] I'm just wanting to add that in these basses the J pickup hums. Shielding might help, but from everything OP has said I think the main cause is going to be the j-style pickup having standard single coil hum. I've looked into trying to fix this on my BB425, including pickup replacements and even making a dummy coil to try to make the pickup hum cancelling - none really looked to be a good solution and it's now something i've just (begrudgingly) accepted. Quote Link to comment Share on other sites More sharing options...
solo4652 Posted April 8, 2016 Author Share Posted April 8, 2016 (edited) Thanks folks. Sounds like the hum from my 424 is par for the course, then. It's not a problem at rehearsals or gigs - it just irritates me at home, especially since my other basses (both P-type) are dead quiet. I'll not go poking around any more in the cavities because I'll probably end up doing more harm than good. Having sold my Fender P yesterday to make room for a BB1024, I'd better check; Does the BB1024 suffer from the same humming? Edited April 8, 2016 by solo4652 Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted April 8, 2016 Share Posted April 8, 2016 [quote name='solo4652' timestamp='1460117643' post='3022737'] Thanks folks. Sounds like the hum from my 424 is par for the course, then. It's not a problem at rehearsals or gigs - it just irritates me at home, especially since my other basses (both P-type) are dead quiet. I'll not go poking around any more in the cavities because I'll probably end up doing more harm than good. Having sold my Fender P yesterday to make room for a BB1024, I'd better check; Does the BB1024 suffer from the same humming? [/quote] Had a 1025X and didn't notice any noise. When you're at home try using your gear in different rooms and different wall sokets, also try turning off any lighting that may be on, sometimes they're just picking up interference from other apliances hooked on the same line. Quote Link to comment Share on other sites More sharing options...
bornagainbass65 Posted April 8, 2016 Share Posted April 8, 2016 The bass whisperer mentions single coil hum on his review of the 2024/5, so if it is an issue, it affects all the Yamaha BBs, even top of the range. I recently bought a 1025 and in the process had a chat with the guitar/bass tech guy at the Yamaha centre in London. I specifically asked about single coil hum and, in a nutshell, he said that the hum comes with the territory of having a J pickup. You can shield it, if it bothers you, but you may slightly alter the sound of the pick up in the process. There is a very slight hum on my bass, but only when the J pick up is soloed, and barely noticeable. Part and parcel of having an old school, passive bass. Quote Link to comment Share on other sites More sharing options...
BriNBigD Posted November 19, 2019 Share Posted November 19, 2019 Can you tell me what the wire colors are: hot from neck/bridge and ground from neck/bridge? I need help, please!! Thanks! Brian Quote Link to comment Share on other sites More sharing options...
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