The Last Bass Outpost
Gear Discussion Forums => Bill's Shop: Projects, Mods & Repairs => Topic started by: Pilgrim on August 22, 2010, 10:30:14 AM
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OK, the pickups are in and wires run on the EB-0 - I have an original Gibson humbucker in the neck position and a Model One in the bridge position.
My goal is to connect each pickup to a pot with push/pull switch, and work without a tone control for now. With the sound I'm likely to get out of this combination of pickups, I doubt that I will need to roll off the treble from the signal.
SO - I need to figure out how to wire this. I'm part-way there but am puzzled with how to proceed.
For the Gibson pickup, I really don't need a push-pull, but I have one so I installed it. All I need to do with that pot is leave it in the "push" position and let the signal go through.
For the Model One, I have four wires which don't conform to Dimarzio's normal color scheme: Black / Red / White / Bare. But the pickup is 20+ years old and I assume they've changed it. From testing with an ohm meter, it appears that Black and Red are a pair, and White and Bare are a pair. I want to wire the the connections on the push/pull for the Model One so that UP is one coil of the pickup, DOWN is both coils.
This diagram reflects what I have done so far...but I need help completing it. I'm confused because I can't find any diagrams without tone pots after a pair of humbucker controls.
(http://i83.photobucket.com/albums/j306/apowell1/Electric%20Basses/EB-02small.jpg)
Here's a direct link to the file:
http://i83.photobucket.com/albums/j306/apowell1/Electric%20Basses/EB-02small.jpg
I suspect that I have the Model One wired wrong in any case...but if one of you folks who really understand wiring could help me get these wired as described above and connect to the output jack, I'd br grateful. I have labeled each push/pull contact with letters A-F, and terminals on the pots 1-3.
Ideas?
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You want to coiltap the model one or series-parallel wire it? Remember that in single mode you will have noise.
Also, if you want not to "waste" mudbuckers' push-pull, you could always wire it for out-of-phase with the other pickup.
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I have a diagram in PDF from my Lotto, which seems to be what you want: push/pull (switches) directly after the humbuckers for each of them. Only, I don't know how to share a PDF with you, besides email. Suggestions? :rolleyes:
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Thanks kindly...and email would be dandy! Use the link below my avatar...or... apowell - at - gocougs.wsu.edu
You want to coiltap the model one or series-parallel wire it? Remember that in single mode you will have noise.
Also, if you want not to "waste" mudbuckers' push-pull, you could always wire it for out-of-phase with the other pickup.
Beats me. What does going out of phase get me?
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You've got mail. ;)
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Thanks kindly...and email would be dandy! Use the link below my avatar...or... apowell@gocougs.wsu.edu
Beats me. What does going out of phase get me?
Hey Pilgrim, you might want to edit you email address a bit so as to keep the spambots from picking it up....just saying ;). Do you really want 300 emails about E D or size enhancement ;D
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I already got 'em. I'm SUPER-sized! :P
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Make sure you seek medical attention if after three hours............ ;D :P
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Well, mebbe I should say that my inbox is super-sized. Filters and the delete button are my friends.
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Well, crapola.
I used the info so kindly provided to me here along with some re-interpreting to wire the pair of pots. It's interesting how different diagrams with the same purpose can differ in so many ways.
At any rate, after assembling, not a sound out of it. Clearly, something is not right. I may try to draw up what I've done and post it so someone can point out whatever bonehead mistake I made.
I'm finding it a bit difficult to interpret diagrams that all have tone pots in the circuit...which I don't have. What I've done is to bypass the tone part of the diagram, twist together and connect the positive and negative outputs from both pickups directly to the output jack. If that's an error, I would be glad if someone tells me......
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If you can find them I love the very small alligator clips for something like this - leave your circuit outside of the bass and you can experiment away with little pain, suffereing and soldering. Once you like what you have you can make it permanent.
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I'm still working on it. I decided that since the original mudbucker only has two wires of output, there was no point in using a push-pull on it, so I got a standard 500K pot for that pickup. BUT - I'm still doing something wrong and I'm on about my third attempt.
There is no tone pot....and I'm having two problems:
1) If I turn either pickup down, it turns them both down.
2) The simple pot works OK, but the push-pull reaches maximum volume with the pot set in the center of its travel, not at the far clockwise setting. If I turn the pot left or right from that center position, the volume is reduced.
I also have some hum in the system that comes and goes with touching and releasing the pots, but it may be a result of whatever error(s) I've made....that's not a real concern yet.
Here is a drawing of exactly what I have at present. Note that I have numbered the tabs on the switch section of the push-pull pot (1-2-3 on the left side, 4-5-6 on the right side) for reference.
Your suggestions on how to solve this are needed and very much appreciated! It really is a poser to me that turning EITHER pot down kills both of them.
(http://i83.photobucket.com/albums/j306/apowell1/Electric%20Basses/NewEB-0wiring.jpg)
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I think you must switch the 3 and 4 lugs of the push pull, you must make the 3 hot and the 4 ground.
As for the volume pots problem, are you sure you have wire them as in the diagram? Because if you put the pickup input on the 2nd lug of the pot instead on the first, you've got this "problem". Gibson calls it "the modern wiring"...
Also, check out all of your grounds and the siognal path, maybe you've got shorts or something.
If you solve those problems, we can talk about out of phase thingies, if you still have the courage ofcourse! ;)
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I'll make the 3-4 swap and see what happens...thanks!
I thought I was putting the pot's OUTput on the middle lug - but sometimes I forget that electricity travels both ways. I'll leave them as is for the time being unless someone can help me with an alternative.
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Hmmmmph. Swapped the pickup leads on 3 & 4 and no joy - same problem. I also added a ground jumper wire between the two pots in an effort to kill the hum, but that didn't work either - it still comes and goes with handling the pots.
I'm about ready to put in two conventional pots with no tone pot - wire the Dimarzio with both coils together - and call it good. I've had this thing on the bench for three weeks since I got the second pickup and I'm ready to stop messing with it and play it.
I don't know whether I'm missing something or the problem is not having the second pot as a buffer of some kind, but the complication of the push-pull is becoming more trouble than it's worth.
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Damn, I was hoping I found the mistake. I'm out of ideas Al, maybe this model one is cursed to work only full-bore. Who knows?
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Well, don't feel bad. I'm still making some kind of mistake even though I've removed the push-pull pots from the circuit. here's what I have now...and it STILL turns the volume off when I turn down EITHER pot...and what's more, when I touch the cover for the mudbucker, I get static. Seems like there's another ground wire needed.
Stepping back, since whenever I turn either pickup down it turns down the volume of both pickups, it seems like they're wired in series...so that either pot can kill the circuit. I really thought this was wiring in parallel so the volume pots can work independently.
Does anyone see what basic mistake I'm making? This seems SO SIMPLE......but right now it sounds like crap and I can't balance the pickups wth the volume controls. Frustration is setting in.
(http://i83.photobucket.com/albums/j306/apowell1/Electric%20Basses/EB-0twobasicpots.jpg)
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No, the diagram is ok, maybe one of the pickups (or both) has some grounding problems?
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i am not an expert on wiring but it occurred to me that those pickups might be loading each other in your present parallel configuration. if it were me, i would 1) mock up a wiring loom on some plywood (so i couild switch configurations easily while on a bench) and 2) go for a wired together Dimarzio with a three position pickup switch and about a 47k resistor between each volume pot and the switch to keep them from loading one another. this value should not let you lose any appreciable volume but it should be enough to keep the pups from loading one another. a 100k of resistance shouldn't be any bother to a high impedence amp.
AND i would ask PBG.
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i am not an expert on wiring but it occurred to me that those pickups might be loading each other in your present parallel configuration. if it were me, i would 1) mock up a wiring loom on some plywood (so i couild switch configurations easily while on a bench) and 2) go for a wired together Dimarzio with a three position pickup switch and about a 47k resistor between each volume pot and the switch to keep them from loading one another. this value should not let you lose any appreciable volume but it should be enough to keep the pups from loading one another. a 100k of resistance shouldn't be any bother to a high impedence amp.
AND i would ask PBG.
Hmmm...I wonder if I could just insert a 47K resistor in the output wire of each pickup between it and the jack...? I'm reluctant to pull the pickups, as that would be required to breadboard the setup. A good idea, but I'm reluctant to take that step since the wires are hard to pull through the channels.
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i would try it. i was not telling you to pull the pups but i was thinking of extending some wires and ground wires on a temp basis. good point, too much work about feeding wires through a small opening. if you would pull the pups then you would not be able to test it live.
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Cool. Might do that!
I will also PM PGB and see if he has any ideas.
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if it works and you still have a hummm, then i would ask PBG about how to determine if that Dimarzio is in phase and i would also check the Bucker to see if it has ever been "spliced". also ask him about the value of the resistors. i would try it your way first to save yourself any extra work.
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I didn't follow what you were trying to do with the push-pull pot, but the way you have it now, don't you need to wire it like a standard J with the hot going to the center lug? This should make each volume control independent again.
See http://www.axesrus.com/images/BASS1.jpg and omit the tone control.
Also see http://www.stewmac.com/freeinfo/Electronics/Misc/i-4000/i-4000_4.html : "Reversed (Jazz Bass) wiring for independent control of volume."
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Dave, I think your last link explains it well. I haven't seen that option for wiring before - but it will be easy to try. Looks like a winner.
I'll give that configuration a try tomorrow evening. Getting late tonight....
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Original stack pot Jazz wiring. Note resistors to eliminate 'crosstalk' and other voodoo. Would something like this be helpful? Works great on my stack pots to make volumes and tones completely independent.
(http://i976.photobucket.com/albums/ae241/cata1d0/2010%20Fenderbird/4A_12_SB.jpg)
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Sounds like the combination of wiring change and resistors if needed will get it done!
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I like stack pots in a 2 pup configuration to get the max sound possibilities in a compact layout.
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I like stack pots in a 2 pup configuration to get the max sound possibilities in a compact layout.
I like 'em too and may end up going that way eventually. For the moment I'm trying to stay with the two Gibby high-hat knobs. If I can't get what I want out of this setup without the tone controls, going stack-knob makes sense.
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I like 'em too and may end up going that way eventually. For the moment I'm trying to stay with the two Gibby high-hat knobs. If I can't get what I want out of this setup without the tone controls, going stack-knob makes sense.
Here's hoping you'll get what you want out of the 2 vol setup. I have 1 vol, 1 tone and a 3 way switch on my converted EBO and usually keep the tone maxed and both pups on.
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Crikey - sounds like your haveing a real nightmare there... I still haven't figured out where mine's gone screwy... don't envy you one little bit...
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Some good news - the wiring change Dave suggested (swapping the input and output leads) fixed the volume control problem! Now each pickup operates independently.
Dang, that mudbucker is HOT!!!!
Two things left to fix:
1) The pickups must be out of phase with each other; when I raise both volumes up full, the output gain is reduced and the sound is much less deep.
2) whenever the mudbucker is turned up and I don't touch the strings, I have slight hum. When I touch the strings it dies out, but when I touch the metal mudbucker cover, I get a LOT of hum. I conclude I need another ground wire from the 'bucker to the ground system.
Any comments on how to change the phase of one pickup? I can easily reverse the input and output connections on one of the two (back to its original setting), if that will do it.
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Yup, that would do the trick, just swap the hot and ground on one of the pickups. As for the grounding problem of the mudbucker, check with a multimeter if its ground is soldered ok on the chassis of the pickup or it has corroded or something.
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1) The pickups must be out of phase with each other; when I raise both volumes up full, the output gain is reduced and the sound is much less deep.
Try swapping the polarity first, but don't be surprised to find out that what you're hearing is phase cancellation from the distance the pickups are apart. I have a couple of Jazz basses that get quieter with both pickups on, and they're wired correctly. That is still phase cancellation, but it is due to the difference in phase caused by the difference in string motion and not electronic polarity.
2) whenever the mudbucker is turned up and I don't touch the strings, I have slight hum. When I touch the strings it dies out, but when I touch the metal mudbucker cover, I get a LOT of hum. I conclude I need another ground wire from the 'bucker to the ground system.
Are you using shielded wire or two separate leads? If you're using separates, I recommend changing out the mudbucker to shielded wire and tying the shield to its cover.
Any comments on how to change the phase of one pickup? I can easily reverse the input and output connections on one of the two (back to its original setting), if that will do it.
Reversing the connections will change the polarity of the pickup, which will change the phase of its output AC, but be aware that polarity and phase are not the same things, though the terms are often used interchangably.
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Try swapping the polarity first, but don't be surprised to find out that what you're hearing is phase cancellation from the distance the pickups are apart. I have a couple of Jazz basses that get quieter with both pickups on, and they're wired correctly. That is still phase cancellation, but it is due to the difference in phase caused by the difference in string motion and not electronic polarity.
Are you using shielded wire or two separate leads? If you're using separates, I recommend changing out the mudbucker to shielded wire and tying the shield to its cover.
Reversing the connections will change the polarity of the pickup, which will change the phase of its output AC, but be aware that polarity and phase are not the same things, though the terms are often used interchangably.
I tried swapping polarity on the mudbucker but that just killed its gain - no sound. I returned the leads to their functional settings.
The mudbucker's shield covers part of the wire length but doesn't run to the pot. I soldered an extra ground wire onto the shield that did still exist and connected it to the cover - the pickup was well grounded to the same shield. No joy, no change in hum.
You may very well be right that the pickups are canceling each other out of differences in string motion. Something is certainly canceling out, and it's reducing both gain and bass sound. When I have both pickups turned up, the sound is thin but if I turn the Model One down about 20% the gain jumps up and the sound gets fatter.
For the moment it's playable if I only use one pickup at a time. The hum from the mudbucker isn't audible if I don't touch the cover by bracing my thumb against it. I'm at least be able to practice with it. I'm not sure what the next step is, but if I can kill the hum from contacting the mudbucker, I'll be able to use one pickup at a time.
I'll say this - that Gibson pickup is HOT and LOUD. It's amazingly powerful and wooly sounding!
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The mudbucker's shield covers part of the wire length but doesn't run to the pot. I soldered an extra ground wire onto the shield that did still exist and connected it to the cover - the pickup was well grounded to the same shield. No joy, no change in hum.
I suggest trying it straight to the jack to make sure it's not the pot.
You may very well be right that the pickups are canceling each other out of differences in string motion. Something is certainly canceling out, and it's reducing both gain and bass sound. When I have both pickups turned up, the sound is thin but if I turn the Model One down about 20% the gain jumps up and the sound gets fatter.
That sounds like the type of phase cancellation Psycho Bass Guy described (difference in string motion, not polarity). It's just the way these two pickups interact at those positions and distances apart.
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I suggest trying it straight to the jack to make sure it's not the pot.
Yeah. On a two-lead humbucker, there should be no difference in soloed output by changing polarity. The hum may be coming from the pot.
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You can try something else for the pickup cancellation, that trick some old Ricks have, solder a small capacitor (ricks have a 0.0047uF I think) in bridge pickup hot wire. That will choke bridge pickup's bass frequencies and they will not cancel the bass frequencies of the mudbucker when used together.
The disadvantage is that bridge pickup soloed would sound kinda tinny. You can read about that here:
http://www.joeysbassnotes.com/Rick%20maint.htm#cmod
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Hey Dave and PBG, sounds like a good idea to try going direct to the jack. At least with the push-pull switches out of that bass, it's a LOT easier to mod the wiring. The pots are CTS (supposed to be good ones), but that doesn't mean I haven't done something creative to induce hum.
ExA, I'll hold your idea as backup.
The whole string-cancellation thing is kind of a surprise to me, considering how many different wacky multi-pickup installs I've seen, none of which mentioned encountering that problem. If it keeps up, I may find that it's a reason to yank that Model One and come up with a black PG square to cover the hole. OTOH, there is a difference in the sound of the two pickups, so even if I can't use both at once, having the option of using one or the other does slightly increase the versatility of the bass.
So far, I'd say the differences in the pickups are:
1) The Gibson mudbucker is hotter, puts out more gain, and also is a wooly mammoth. Definitely a vintage EB-0 wool/mud sound. I dig it a lot. Using this pickup, I don't think I'd need my overdrive pedal - it sounds overdriven in its natural state.
2) The Dimarzio is less hot and puts out 80-90% as much gain, and if the Gibby pickup is a wooly mammoth, the Dimarzio is a wooly buffalo. It's not quite as rough and is slightly more clear, but definitely nothing like a modern-sounding pickup for clean sound.
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OK - with the pot for the Model One disconnected from the jack, the Gibson humbucker still hums like a wild beast. Even with the pickup cover grounded to the pickup, I get hum when I touch the metal cover.
I guess the next step is to replace the pot with a different new 500K ohm pot that I have...and see what happens.
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The fact that you got no sound when you switched leads makes me think the problem isn't with the pickup. Can't say for sure, though. IIRC Bill had that mudbucker in a bass but after he sold it to me, I never did get around to my project.
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How good is your ground connection to the bridge?
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How good is your ground connection to the bridge?
Good question. WHERE does the ground wire run in these darn EB-0 models? I can't see anything running directly to the bridge. There's a "mystery wire" coming out of the body next to the jack, but I haven't figured out where it goes.
When I got the bass there was a bit of what looked like solder-wick wire folded up at the bottom of the bridge post hole nearest to the pots, but it wasn't attached to anything. I removed it so the post would screw in fully.
Maybe I'll just clip a jumper cable onto the shield side of the jack and run it to the bridge. Hadn't thought of that before, but it would ground the bridge and strings for sure.
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You must change the title of the topic to something like "The quest for the holy ground"! :D
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Usually, the mystery wire exits out of the top of the control cavity. The other end is supposed to be wedged between the lower bridge insert and the body. If it isn't making good contact, that might be your problem. Run a temporary jumper from the jack to the bridge to see if that helps.
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Usually, the mystery wire exits out of the top of the control cavity. The other end is supposed to be wedged between the lower bridge insert and the body. If it isn't making good contact, that might be your problem. Run a temporary jumper from the jack to the bridge to see if that helps.
<Mr. Burns mode: ON>
Excellent! (Rubs hands)
<MB mode: off>
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SORRY to drag this out, but........................................
I have done more testing and simplified things.
Let's consider my EB-0 to have only one pickup, the Gibson mudbucker in the neck position (the other pickup is completely disconnected.) Perhaps that will help me figure out what's going on.
Here's the situation.....
- The mudbucker pickup is wired to 500K ohm pot.
- Grounds run to the jack shield connection,
- The live wire runs to the jack tip connection.
- The ground/shield wire from the mudbucker is also wired to the metal pickup cover to assure that it's grounded.
When I connect the bass to an amp, I get little or no hum when I touch the strings...but when I prop my thumb on the pickup cover to pluck, I get loud hum.
I tried connecting a ground wire from the bass's internal bridge ground wire and the ground side of the jack around to the bridge.
- This results in hum all the time.
- When I touch the strings, the hum is silenced.
- When I prop my thumb on the pickup cover with my fingers on the strings, the hum gets louder but not too bad.
- If I touch the pickup cover without putting my fingers on the strings, the hum is quite loud.
Could it be a problem with the way the pickup is wired? It has the original leads including shield for about 2 inches, then the leads were cut. I've had to graft extension wires on at that point.
There is clearly something going on with the grounding, but logic fails me in my attempt to understand what. Can someone help me reason this out?
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Try this: connect the mudbucker directly to the jack (no pot) and also connect a ground wire from the pickup to the strings (with an alligator clip) and check again. If the problem dissapears, then its the bass' ground that has some problem. If the problem persists, your mudbucker is sick.
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Definitely worth a try!
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Latest report with pickup wired direct to output jack, no pot in between:
- No finger contact with strings: slight hum.
- No finger contact with strings AND touch the metal pickup cover: loud hum.
- Touch strings with finger: no hum.
- Touch strings with finger AND touch metal pickup cover: moderate hum.
- Adding a ground wire between the ground side of the output jack and the bridge has no effect - does not reduce hum.
Any ideas on what to try now?
I think that to make the bass functional for the time being, I'll connect the Dimarzio Model one and just leave the mudbucker out of the circuit entirely.
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That don't sound healthy...
Do you have a multimeter...?
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Try taking off the metal cover completely and see what happens. And after that, try wiring the metal cover to the ground side of the output jack instead of wiring to the shield/ground of the pickup.
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Try taking off the metal cover completely and see what happens. And after that, try wiring the metal cover to the ground side of the output jack instead of wiring to the shield/ground of the pickup.
+1
The cover is contacting something it shouldn't.
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On my old EB-0, I had run a ground from the mudbucker's metal frame/enclosure to one of the mounting screws on the cover. Prior to doing that, it hummed more than Jenna Jameson when I touched the cover as you describe.
My EB-3 does the exact same thing, and I still need to add a ground there. I like to use the mud's cover as a thumbrest, but as it stands now I avoid it because it starts to become an instrument of its own!
Not sure if this is the same grounding problem you are running into, but its something to check...
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Prior to doing that, it hummed more than Jenna Jameson when I touched the cover as you describe.
[outpost mode=on] Maybe your fingering was too intense? :D [outpost mode=off]
Definately worth a try, if it doesn't work then try to isolate the mud cover from the rest of the pickup, with duct tape or something.
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Try taking off the metal cover completely and see what happens. And after that, try wiring the metal cover to the ground side of the output jack instead of wiring to the shield/ground of the pickup.
Can do!
On my old EB-0, I had run a ground from the mudbucker's metal frame/enclosure to one of the mounting screws on the cover. Prior to doing that, it hummed more than Jenna Jameson when I touched the cover as you describe.
A rather delightful simile! I have a wire from the shield side of the pickup's output to the cover, but it's not doing the job. I'll try the connection suggested at the top of this reply next....or maybe I should just call Jenna. I suppose I can always ask my wife if she has any ideas.
You guys are INCREDIBLY patient! I appreciate your ongoing help. And BTW, yes, I have a number of multimeters, digital and analog.
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Check everything to ground, including covers... ensure that all metalwork not part of the circuit is common with the ground, ie as close to zero ohms as possible...
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All of you have had a piece of it - I got back in there and removed the cover - hum still present.
Then I tried running a ground wire from the body of the pickup to the ground on the output jack - hum still present.
Then I thought it over....and tried reversing the leads from the pickup. Something that someone wrote in the last few posts this thread sparked the idea.
HUM GONE.
Maybe I saw things wrong when installing the pickup - maybe the wiring was somewhat deceptive, as this pickup has been through other sets of hands - but reversing the leads solved the problem. No hum with or without pickup cover present. How can you get more basic than that???
Now I'll try to re-connect both pickups (I have have the wiring totally screwed around by this point) and see what happens. But if nothing else, I now have a functional Gibson pickup, so I can at least play it the way it was designed...with one pickup. Adding the second one will just add options!
EDIT...............................
I now have both pickups working! The Model One is a lot brighter than the Gibson, and in alternating volume, I find it's not nearly as loud..but it's quite usable. Also, if I have both volume puts wide open there is a bit of signal cancellation at the max settings. So far, I like the sound best with either the mudbucker up full and the Dimarzio off, or the Dimarzio down a tad at about 7 of 10. It adds just a hint of brightness at that setting.
Darn thing is finally playable! Hot-ta, hot-ta damn!
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Yup! That is what I was going to suggest next, after testing without the cover. Because it would mean that the cover was acting like the lead and by touching it you would be sending the noise fpicked up from your body to the system.
So, by reversing the leads you mean you connected the shield/ground from the pickup wire to the lead of the jack? Or you had it all wrong from start and now you correctly wired the shield/ground to the ground of the jack? Or is it that the wired from the pickup is not the shielded type?
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Yay!
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So, by reversing the leads you mean you connected the shield/ground from the pickup wire to the lead of the jack? Or you had it all wrong from start and now you correctly wired the shield/ground to the ground of the jack? Or is it that the wired from the pickup is not the shielded type?
I had the pickup wired direct to the output jack - so I just reversed the leads. I originally thought I had the wrap wiring to the jack tip and the shield to the shaft/ground, but evidently not. Reversing them eliminated the hum.
This feels like the Homer Simpson moment: "D'OH!"
Next step was to re-connect the 'bucker pickup wires to the control pot, but reversed from the original (humming) configuration. Then the output of that control pot and the other one were connected to the output jack. No hum!!
Dave, Yay is both highly appropriate and a massive understatement. Thanks to ALL of you for hanging in with me and providing such great suggestions!
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Now you can crank out the mud! :P
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Cranking out the mud could be a dangerous expression in Australia... :o
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I'm thinkin' that EB-0 was made to play Jack the Ripper! it ought to sound nice and nasty.....
I shall try to avoid making listeners crank out the mud. :o
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Aussie expressions are a mystery to me, I admit it.