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Weak neck pickup
Posted: Sun Jul 05, 2015 12:30 am
by farace
So I picked up this '83 4003 this morning that I described in another thread, and I've spent the day trying to sort out some minor issues (sorting out the action (which included the bridge being turned around 180 degrees), and having one of the Grovers explode on me (I staked them all so it's no longer an issue). What's vexing me now is that the neck pickup is significantly lower in output than the bridge pickup. I followed the schematic and can't find any obvious wiring issues, and both pickups are 4-5mm beneath the strings--as high as the neck pickup will go.
Clearly the neck should be booming louder than the bridge (especially with the .0047 mfd cap still in place on the bridge PU). Any suggestions for a possible cause, or should I resign myself to replacing it?
Thanks,
--Bob
Re: Weak neck pickup
Posted: Sun Jul 05, 2015 4:56 am
by ilan
Here's a quick $6 fix that I learned from Ted Staberow:
Order this neodymium magnet from K&J and just put it under the neck pickup. Should boost the output significantly.
Re: Weak neck pickup
Posted: Sun Jul 05, 2015 8:53 am
by farace
Ooh, that looks like fun. Quick question on this, do I just put it underneath in whatever orientation it naturally wants to place itself, or does it need to be forced (e.g., glued) in a way it doesn't want to go? The reason I ask is because I don't know which way the stock magnet is polarized--end to end or top to bottom for instance--and I'm wondering if, say, it is end to end, the North Pole of the accessory magnet will want to be oriented to the South Pole of the stock magnet, and if this would be a problem.
It does seem like a six-dollar solution to a hundred-dollar problem though. Thanks!
--Bob
Re: Weak neck pickup
Posted: Sun Jul 05, 2015 11:38 am
by songdog
Do you have an ohmmeter? Have you checked the resistance of the two pickups and the associated volume pots? You don't even have to unsolder anything, just check with the volume full up for the pickup resistance, and all the way down for the pot resistance.
Also, did you clean the contacts in the selector switch and the switch in the mono jack? A little corrosion here could make a big difference.
Are you testing using the mono jack? Try a stereo cable in the Ric-o-sound jack, or just a mono cable inserted there to the first click to get the neck pickup, all the way for the bridge pickup.
Someone here can probably tell you exactly what the pickup resistance should be; but the pickups should be within about 20% of 10K, and the volume pots around 250K (I think the change to 330K was in the 90s, but again the experts will remember the details).
By the way, that is a stunning looking bass!
Re: Weak neck pickup
Posted: Sun Jul 05, 2015 11:57 am
by farace
Thanks! I've done some of those things. I'll run through it all again later; we're headed out to a party (though to be honest I'd rather stay home and fiddle with the bass).
--Bob
Re: Weak neck pickup
Posted: Sun Jul 05, 2015 1:05 pm
by rictified
farace wrote:Ooh, that looks like fun. Quick question on this, do I just put it underneath in whatever orientation it naturally wants to place itself, or does it need to be forced (e.g., glued) in a way it doesn't want to go? The reason I ask is because I don't know which way the stock magnet is polarized--end to end or top to bottom for instance--and I'm wondering if, say, it is end to end, the North Pole of the accessory magnet will want to be oriented to the South Pole of the stock magnet, and if this would be a problem.
It does seem like a six-dollar solution to a hundred-dollar problem though. Thanks!
--Bob
Re: Weak neck pickup
Posted: Sun Jul 05, 2015 1:12 pm
by Ontario_RIC_fan
Bob - I am not sure about basses. But in the late 70s early 80s - RIC deliberately but a weak / strong pick up configuration in guitars with Rick-o-sound to provide maximum contrast when using the blend knob.
So it may have left the factory that way.
Perhaps some one with more bass knowledge then I - may chime in with more info.
Re: Weak neck pickup
Posted: Tue Jul 07, 2015 10:58 am
by farace
I've been busy, so it took me a couple of days, but I just checked the volume pots, and the one for the neck pickup shows no change in resistance as I turn it. It's basically turned down permanently. I'll have to look more closely at it when I get home from work tonight and see if it's a fix or a replace, but I figure for the short term I can bypass it until I get a new pot. Thanks for suggesting checking the pots; I've never had one go bad in a way that the resistance doesn't change. Dirty, scratchy, intermittent yes, but never as if the wiper is stuck in one place.
--Bob
Re: Weak neck pickup
Posted: Tue Jul 07, 2015 8:19 pm
by farace
Okay, this is infuriating, made worse by my VOM seeming not to be working correctly.
Upon opening the control compartment (I have to say I've learned to love the two-piece pickguard for this), the neck volume control seems to be working correctly, even though if I test the end of a guitar cable while the neck pickup only is switched on, the resistance doesn't change. (The resistance changes as expected for the bridge pickup.) If I test the resistance directly at the legs of the pot, it changes when turned.
More telling, though, was that I unsoldered both the wire from the selector switch and the wire to the output jack from the volume pot and soldered them directly together, and got no increase in output.
This is making my head hurt.
Re: Weak neck pickup
Posted: Tue Jul 07, 2015 10:24 pm
by cassius987
I wouldn't recommend increasing the magnetic strength of the neck pickup. In my experience that only makes things sound worse because of how flexible the strings are at that segment. (Too much magnetic pull messes up their normal vibration; I have had "setup problems" on the fingerboard caused by a neck pickup in the past, which were fixed by backing it off.)
If I understand your last post, it sounds as if your neck volume pot was not really working properly at least by the time you opened the cavity up. It may have worked before but it is common for opening the cavity and pulling the wires about to mess up a connection now and then.
I would also caution that in many cases the neck pickup only really comes alive through good house speakers as most bass rigs I have played through just don't capture its thump as well. The exception would be enhanced low range cabs like fEARful designs and the Barefaced Big Baby model range. When I record with a Ric, the thump that gets recorded direct from the neck pickup is usually a lot deeper sounding than what a normal cab reproduces.
Re: Weak neck pickup
Posted: Tue Jul 07, 2015 11:35 pm
by farace
Thank you. No, it seems I'm getting weak output. There's quite a pronounced difference from what I experience with my 2015 4003, and also what I remember from years ago when I had a'78 4001. If you heard the difference between the bridge and neck pickups, you'd say, "oh, it's that bad."
As for the volume pot, I may have not been very clear. When I tested it without opening it up, by plugging a guitar cable into the mono output, putting my ohmmeter at the other end of the cable, and switching to just the neck pickup, it appeared the pot was not working. However, upon opening up the control cavity and putting my ohmmeter directly on the pot, I can see that the resistance varies just like the bridge volume pot. Plus, when I bypassed the volume pot, I got no increase in volume. It's seeming as if something is awry with the pickup.
Any other suggestions as to what to test are welcome. Otherwise I get the feeling I'm on the search for a pickup. (Both RIC and Pick of the Rics websites say they're out of stock.)
--Bob
Re: Weak neck pickup
Posted: Wed Jul 08, 2015 12:15 am
by farace
Also, while I'm thinking about it, and especially since neck pickups seem to be out of stock, I'm starting to think about getting this one rewound. Any recommendations and/or caveats are greatly appreciated.
Re: Weak neck pickup
Posted: Wed Jul 08, 2015 8:46 am
by fran4001
Our own Sergio Silva does great rewinds, and he's done lots of ours here, mine included. He runs the "Winding Up With The Best" forum here in the Tech section. Message him!
Re: Weak neck pickup
Posted: Wed Jul 08, 2015 10:50 am
by iiipopes
The weak/strong pickup combination was used mostly on the guitars of the 70's and early '80's, with an underwound bridge pickup for maximum bright and an overwound neck pickup for maximum mellow. I have two instruments from 1981 that both exhibited that aspect until I reworked the stock high-gain pickups.
In reworking the pickups, one was a little weak, and it turned out a little film of magnet glue had worked itself between the bottom of the pole pieces and the bar magnet. I removed the magnet, scraped the bottoms of the poles clean, made sure everything was level so that all the poles made good contact with the magnet, reinstalled everything, and all the volume and tone came back.
Re: Weak neck pickup
Posted: Wed Jul 08, 2015 11:42 am
by farace
iiipopes wrote:The weak/strong pickup combination was used mostly on the guitars of the 70's and early '80's, with an underwound bridge pickup for maximum bright and an overwound neck pickup for maximum mellow. I have two instruments from 1981 that both exhibited that aspect until I reworked the stock high-gain pickups.
Hmmm. That's backward from what I'm experiencing, with a weak neck pickup. I'd expect more output from the neck even if the windings were equal, simply because the natural vibration of the strings will be wider there.
In reworking the pickups, one was a little weak, and it turned out a little film of magnet glue had worked itself between the bottom of the pole pieces and the bar magnet. I removed the magnet, scraped the bottoms of the poles clean, made sure everything was level so that all the poles made good contact with the magnet, reinstalled everything, and all the volume and tone came back.
Thanks, I'll definitely check into that before sending the pickup off for rewinding. I'll be swinging by my parents' house to borrow my dad's soldering gun to desolder the ground braid from the back of the pot; my little soldering pencils just aren't as well suited to that. Having the pickup out will make it easier to work on. Is the bar magnet glued tightly? In other words, is it a flexible glue that can be carefully pried up?
It probably wouldn't confound me so much if the pickup was outright
dead, but it's weak; it's working to some extent, so it's not a broken winding, leading me to look at resistances and dirt/corrosion and stuff. The contact between polepieces and magnet appeals to my logic at this point.
If it comes down to rewinding, I'll look into Sergio. Last night I also sent email to Tom Brantley.
Thanks again!