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Post by JohnH on Jun 18, 2010 22:30:40 GMT -5
Raz - your readings are clear enough, but also puzzling.
The neck readings are consistent, so lets just consider the bridge. he 'all knobs down' reading at 7.00k is fine, corresponding to normal humbucker. But when you pull S3 and S4, you also get 7.00k, indicating that both coils are still involved. The diagram wiring cannot do this, with S3 and S4 pulled, the bridge white wire is not connected to anything.
So all I can suggest right now is have really really careful look at S3 and S4 wiring, and see if you spot any difference, and look for any solder blobs or hairs of wire that may be shorting something, or loose joints.
One more thought - do you know what your pickup type is? It would be good to know what the dc resistance of the pickups is supposed to be. I am assuming that you have a medium sort of humbucker at the bridge, in which the two coils in series gived you the 7k reading (including pot). Is there any possibility however that that is just one coil and that a full humbucker resistance for that pup should be twice that? ie a very hot 14k? If that was the case, maybe look for a wisp of wire or other shorted connection between the short black wire across the lower (in the diagram) lugs of S4, and the ground tab on that switch - just a possibility I dont know.
and another idea... select bridge only, S1 down, and plug in. turn up amp until some buzz hum happens. Now step through the 4 combinations of S3 and S4 up and down and rate the volume level of hum from lowest to highest. Do you think you are getting humcancelling in all knobs down? or parallel mode? (with s4 up)
John
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Post by JohnH on Jun 19, 2010 8:57:54 GMT -5
Raz - further investigation based on your observations of point 8 in your post above: The following diagram moves one wire at s3 (see thick blue wire - replacing a thin black wire that was going to ground). This is indeed an error that I will humbly own up to, although it wont fix the other issues. What was happening though was that the S3 switch was taking the central connection of the neck humbucker (green/black) al the way to true ground, which is OK execpt when it is supposed to be in series with the bridge humbucker (S1 pulled), in which case it was not only bypassing one neck coil, but also the whole of the bridge pickup. The clue was in the exact resistance reading of 4.25k, which was the same as the neck coil alone and showed that the bridge was being bypassed. Well, things like that happen with a new design. But please consider the other points in my posts above and lets see what else can be sorted out. cheers John
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Post by Raz59 on Jun 19, 2010 18:00:28 GMT -5
Knowing the DC resistances of my pickups would be very useful...because 7,00 KΩ for an Epiphone bridge humbucker is...nothing short of suspicious. I don't know of a way to confirm the resistances of my pickups without having to de-solder them from the guitar and reading each coil individually...
The controls are all tightly soldered and protected, so I can't get enough space to correctly read them.
As for hums and buzzes. My guitar right now is like an antenna for radio signals. I have to turn off my TV in order to play without additional noise. And my house doesn't have any central ground connection, so take that into account.
I recently acquired a 30-watt soldering iron, so I will correct the wiring as per your new revision of the diagram. I will try to report back soon.
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Post by JohnH on Jun 19, 2010 18:06:07 GMT -5
raz - to check your coil resistances, you can just unsolder one end of one coil, and measure from there to the wire corresponding to the other end of that coil - see the diagram.
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Post by Raz59 on Jun 19, 2010 20:29:41 GMT -5
The wiring is now corrected, as per the diagram you posted. I was afraid that I might have done a cold solder joint with the little soldering experience I have...let's hope that new wire will hold on! And I do get another resistance value when S1, S2 and S3 are pulled. Much, much higher than 4,25 KΩ, it is now 11,25 KΩ, which supposedly means that the bridge humbucker is no longer being bypassed completely. Again, I am very thankful for your help in this little project of mine. Now, about reading the pup's resistances: I'm not at all comfortable with the idea of unsoldering more wires as it is very troublesome to poke around the cavity with a hot iron and trying to avoid burning all that PVC. And keep in mind that I get a lot of hum and noise from this setup. And John, I suspect that the bridge humbucker is indeed 14K...if you analyze my situation mathematically, two coils rated at 7K, when connected in parallel put out a resistance of exactly 3,5K and that is mysteriously the case when S1 is pulled...
As for rating the volume of the hum: by selecting the bridge and with S1 down, I get roughly the same amount of 50Hz ground hum with all the four possible combinations of S3 an S4.
So where are we right now? I've got a neck pickup whose coils are out-of-phase with each other; I've got a bridge pickup whose slug coil is always off; the S2 (phase switch) is redundant, I always get an out-of-phase tone whether it's pushed or pulled. Quite a predicament!
One question though. If I manage to correct the phase of just the neck humbucker, will that correct the functionality of S2?
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Post by JohnH on Jun 19, 2010 20:47:34 GMT -5
The overall series/parallel is now working it seems, we are getting the 4.25 from the neck plus 7 from the bridge =11.25
Things to do:
Take that extra look at the S3 and S4 wiring, particularly see if there are any short circuits, to ground
get inside, and without unsoldering, get your meter measuring resistance on the bridge pickup wires directly Do green and red, red and white, white and black, red and white. Do all those for all knobs in, s4 only pulled, s3 only pulled and both pulled. For these tests, s1 is down, main toggle to neck. That's 16 readings - we should be able to work out something from that. Particularly, white and black with s3 and s4 pulled should be one bridge coil, and not influenced by anything else.
On the neck pup, swapping wires should fix most of its issues, but Id rather know more first.
John
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Post by Raz59 on Jun 19, 2010 22:04:38 GMT -5
Before I go into the tricky job of reading resistances between the 4 wires of the bridge wires, here's one thing I spotted: see how the S4 switch is wired? I think that black wire is soldered to the top pin and then to the ground. And here's what I think is going on: Concentrate on the blue wire. Is this a problem?
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Post by JohnH on Jun 19, 2010 22:22:59 GMT -5
Mate! that is not only A problem, it could be THE problem or at least one of them....
It is shunting your slug coil to ground, when in series mode. Beter fix and repeat a few of the basic resistance tests with the bridge pickup
john
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Post by Raz59 on Jun 19, 2010 22:42:20 GMT -5
How the hell did the luthier manage to solder this simple wire into that pin?? It boggles my mind...ah well, I will deal with it soon enough. So, to treat this problem, I have to unsolder the piece of bare wire that meets the "series link" of the bridge pickup located in S4. I'll also have to cut a bit of PVC to cover it from the other metallic parts, seeing as it is veeeeeeeery close to them. Luckily that will be the fault that's causing the permanent bridge single coil.
I won't deal with problem until 8 hours from now (sleep time).
And I'll ask this question again because it seems it went under the radar: John, if I manage to correct the phase of the neck humbucker by switching some wires around, will that correct the overall phase and return functionality to S2? Because right now, S2 is redundant and I'm picking up a lot of noise and ground hum in all positions!
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Post by JohnH on Jun 19, 2010 22:56:29 GMT -5
Good, and yes, I think judicous wire swapping of the neck will correct it. Except I am still concerned by an earlier commnent that the body of the neck pup may be actually connected to one of the coil leads. I will work out what to swap.
Advice - as you start to fix things - work carefully, and do one thing at a time and check it. Also, you dont really need to use insulation - air is a good insulator, if you carefully bend the wires so you can see a gap between them as separate.
Also, if you are not that experienced with soldering, practice first. Heat each part separately in order to tin with melted solder, which should flow like water to make intimate contact, not stand like a bead. The soldering iron tip shuld have a little melted solder on it, heat the work, then apply solder to the hot wire that you are joining (not just to the iron). Bring the two tinned parts together and heat so that th solder flows wetly, adding a bit more solder if needed. The joint should be stringer than the wires
john
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Post by JohnH on Jun 19, 2010 23:23:12 GMT -5
When you have done that fix to S4, please redo all the phase and resistance tests that you did before , then we can confirm wire swaps at the neck to match the bridge phase.
Also, measure resistance from the neck cover to ground, in all positions of S2 and S3 - it should always be grounded - ie low resistance.
Aren't multimeters great?
J
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Post by Raz59 on Jun 20, 2010 5:25:37 GMT -5
After a surgical procedure involving a blob of solder, a switch terminal and a wire...success! But with a twist! (and my, oh my, what a twist...) I managed to fix the short circuit by removing some solder and ensuring the wire doesn't come in contact with the terminal. After that, I went to do some resistance checking, really quick stuff. John, you were right in suspecting that my bridge pickup was a really hot 14,00 KΩ pup...because it is. The multimeter rates it at 13,92 KΩ when all switches are down!! And finally, S3 and S4 interact like they should, the resistances come up right in regards to single coil and parallel humbucker mode. There's only one thing that bothers me, the little twist I alluded to in the first paragraph...you see, the resistances measured are proof that the guitar is doing what it should... Yet, why does the "bridge humbucker" sound like the "bridge screw coil"?! By this, I mean the following: if I compare both of these sounds, for some reason, the bridge humbucker has LESS volume, MORE noise to sound ratio, MORE brightness - all the traits you'd expect from coil splitting a humbucker! Yet the resistances claim that this is 2 coils connected in series with a whopping DC resistance of 14 KΩ. I bet the guitar is having a good laugh at my expense, take a listen for yourselves: www.soundclick.com/bands/page_songInfo.cfm?bandID=1058374&songID=9300058 (In case this links to my account, the sample I posted is called "Resistive Paradox"). I play a simple chord progression with S3 and S4 down (humbucker), with S4 pulled (parallel coils) and with S3 and S4 pulled (screw coil only). I guarantee you that's the loudest most ballsy screw coil you'll ever hear.
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Post by JohnH on Jun 20, 2010 6:15:35 GMT -5
Definately making progress now. and thanks for the sound clips. Seems to me the two bridge coils are out of phase with each other, so instead of adding up to a more ballsy sound, they are cancelling out the main frequecises, leaving just the high harmonics. And there hums, instead of cabcelling are adding.The single coil sounds great though!
So we can fix this, but you need to repeat the full package of tap tests and pull off tests - the neck seems to have a similar problem, so we will move some wires around, and it should all come to life.
We need to know what the relative phase is of each coil by noting those ups and downs as you did before, and also check which coil is active in single coil modes.
We also need to know what the neck pup cover is connected to - by measuring its resistance to ground as you move S2 and S3.
When you have all that data ready, then I can advise what wires to swap.
but good progress so far!
john
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Post by Raz59 on Jun 20, 2010 7:01:44 GMT -5
Right then, onto the screwdriver pull off A.K.A. phase test:
1. (neck selected, all pp's down) a. neck slug coil - up b. neck screw coil - down
2. (S3 pulled) a. neck slug coil - up b. neck screw coil - up
3. (bridge selected, all pp's down) a. bridge slug - up b. bridge screw - down
4. (S4 pulled) a. bridge slug - up b. bridge screw - down
5. (S3 and S4 pulled, bridge is still selected) a. bridge slug - down b. bridge screw - down
I'm sorry, but I can still make out some sense of the faintest of jumps...I don't exactly know if this is helpful to identifying which coil is active or not. So I took the initiative and I tapped each coil several times with the back of my screwdriver (this one is all metallic), and compared the height of the "jumps". With S3 and S4 pulled, it seems that in the bridge pickup, the screw coil has the higher jumps. As for the neck pickup...with S3 and S4 pulled, the slug coil seems to jump higher (what a predicament I'm in...)
As for the "cover to ground" reading, I will do as follows: I will put one tip of the multimeter on the cover and the other one will be touching the ground wire - and I'm sorry to say, but there is no continuity from the cover to the ground wire connected to the pp's backs...the multimeter doesn't even flinch (speaking of multimeters, we should have a Multimeter Appreciation thread, these things are very handy!)
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Post by JohnH on Jun 20, 2010 7:22:09 GMT -5
OK, the phase tests are cool - i think we have this just about beat. In each of the neck and bridge, the 'all knobs down' settings in which we now believe we have both coils connected, are showing an up and a down in the pull off tests. That shows that both pups have the problem where one coil is out of phase wwith the other. We fix that by swapping leads on one coil.
When you only have one coil wired in, tapping the inactive coil gives a small pulse in the active coil, just due to the magnetic coupling.
When you select a single coil from each pup, we want them in phase, provided S2 is down.
We want the basic in-phase single coils to be the screw coils in each pup
It seems that it is the screw coil that is selected in the bridge pickup, which is correct, but it is out of phase with the slug coil. The neck is slecting the slug coil however.
To correct the Bridge pickup: Reverse the leads on the bridge slug coil by swapping white with black
To correct the Neck pickup: We need to reverse the slug coil wires, and also swap the position of screw and slug coils:
put white where red was put red where green was put green where white was black stays where it was
this should end up with black and red joined together
Thats what I reckon - see if you agree?
John
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Post by Raz59 on Jun 20, 2010 14:42:50 GMT -5
Thanks for the easy to follow instructions John. I did manage to screw up, however. I did what I was supposed to do to the bridge pickup on the NECK pickup. So I swapped the neck's white with the black...on a side note, the neck was sounding in-phase! But I suppose that when I split it, I'm actually using the slug coil because of my mistake...
It did return functionality to S2 (phase inverter), so it's a good sign that this will turn out fine. Time to heat the iron again!
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Post by JohnH on Jun 20, 2010 15:47:52 GMT -5
good, i think what you did confirms we are on the right lines, but if you redo the neck you should be able to get the screw coil when in phase - and it should be humcancelling when you also get the bridge screw coil by pulling S3 and S4.
When you pull S2, 3 and 4, you should get neck slug coil reversed, bridge screw coil so out of phase, but also humcancelling!
John
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Post by Raz59 on Jun 20, 2010 18:47:57 GMT -5
There, all wires swapped...I had to "cheat" sometimes though...the wires were too short, so I had to create extensions and solder them in the respective short wires...Jesus H. Christ, what a hassle. Still, I must have missed something yet again.
Humbuckers sound like humbuckers, and a quick multimeter test considers them like so. The same goes for both single coils and the parallel humbucker. But the parallel humbucker seems to have lost some high frequencies, and it sounds like the single coil. Perhaps it's just me that was used to the humbucker having coils with opposite phases.
The wiring does seem quieter overall. Even though I extended the bare wire of the neck pickup and soldered it to the back of a pot, touching the cover still generates some noise.
And one thing to note: S2, the phase inverter, seems like it's working backwards now...it's already out-of-phase in the down position. So this calls for the phase test.
1. (neck selected, all pp's down) a. neck slug coil - up b. neck screw coil - up
2. (S3 pulled) a. neck slug coil - up b. neck screw coil - too small, can't tell
3. (bridge selected, all pp's down) a. bridge slug - down b. bridge screw - down
4. (S4 pulled) a. bridge slug - down b. bridge screw - down
5. (S3 and S4 pulled, bridge is still selected) a. bridge slug - down b. bridge screw - down
Ah...I think I'm gonna have a chat with the luthier, this is definitely not what I paid for...
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Post by JohnH on Jun 21, 2010 2:32:37 GMT -5
Raz - in phase parallel sounds should sound like a cross between series humbucker and single coil, not quite as bright as single coil and should be humcancelling. If you want to chase the ultra bright sounds, try single coils from each pickup out of phase.
Your current situation, what is the status of eh neck pup now. yesterday you did the intended bridge wire swap on the neck instead. Is that how it still is (thats what it seems like from what you report), or did you undo that and rewire per my notes. Rrelated to this, which two neck wires are now joined togather at the switch?
And are you saying that the neck cover is not connected at all, ie, infinite resistance to ground in all cases? - try fixing (or even just touching) a grounded wire to it - just temporariliy to start with. then there should be no extar noise when you touch it.
Hang in there - getting close now!
John
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Post by Raz59 on Jun 21, 2010 3:15:57 GMT -5
Mental note: I like the sound of an out of phase parallel humbucker. Closest thing to a usable Telecaster tone you will have (it's the second setting in my clip, very "jangly" highs heard there), in my honest opinion. At least this whole mess is educational, I have heard very interesting pickup settings!
I followed your instructions ad verbatim. Yes, I did mention my screw up at first, but I corrected it. The two neck wires that are joined at the switch are the Red and Black ones. And this job of switching wires within the cavity was a very tedious one, so I might have done some mistakes out of distraction, even though it sounds correct right now.
Here are the resistance readings, they seem like the real deal:
1. (neck selected, all pp's down) 8,45KΩ
2. (neck selected, S3 pulled) 4,25 KΩ
3. (bridge selected, all pp's down) 13,90 KΩ
4. (bridge selected, S4 pulled) 3,55 KΩ
5. (S3 and S4 pulled, bridge is still selected) 7,00 KΩ
6. (Both pups selected, all pp's down) 5,25KΩ
7. (S1 pulled, other pp's down) 22,3KΩ (I had to turn the multimeters dial to get this reading!)
8. (S1, S3 and S4 pulled) 11,30KΩ
Yes, the neck cover is not connected, it seems. Like I said, I even had the trouble of building an extension for the bare wire and soldering it to the common ground. But still, the multimeter doesn't give out a reading. (If I put the two probes touching the cover, I do get a reading. Not relevant to the point, but just to show that it is functioning correctly!).
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Post by JohnH on Jun 21, 2010 4:51:25 GMT -5
OK, maybe the last lap....
On the neck humbucker, based on how you have it wired right now, swap green with white. That swaps the phase of the pickup, so your all down settings should be in phase with bridge, and it should cut to a screw coil, as we intend.
J
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Post by Raz59 on Jun 22, 2010 6:31:26 GMT -5
Well, I did the green-white wire swap. But it didn't solve S2's problem, I still hear an out-of-phase tone when S2 is down and the switch is in the middle...And testing the Resistances and the Phases, it is the same as I posted before.
(And I just noticed that the white wire came off, it wasn't properly soldered, the little bugger. I'll deal with this later)
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Post by JohnH on Jun 22, 2010 7:08:37 GMT -5
hmmm...there is something wrong over the last couple of posts. I thought we had it almost cleared up.
If on the neck pickup, if you now have red and black joined at S3, then green and white are now on the two middle lugs of S2?
If so, then swapping green and white does exactly the same as pulling s2, and should have changed the phase of the neck pickup, and also changed which coil is cut with S3. Now if you are saying that swapping green and white changed nothing at all, then that is just not possible. So please have a review of this. In one position of S2, you should get bridge and neck combinations in phase. is that true? is it S2 up or down?
John
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Post by Raz59 on Jun 22, 2010 7:27:21 GMT -5
Yes, red and black are joined at S3 and green and white are on the middle lugs of S2. I believe you when you say it is not possible, but S2 still had the same function. The in phase combination was in the up position, the same as earlier.
And I switched the green and white wires to reverse this, as per your instructions. To my amazement, it was still sounding out-of-phase with S2 down, and the phase of the neck coils were still up-up (in contrast to the bridge coil's down-down).
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Post by JohnH on Jun 22, 2010 15:45:40 GMT -5
so if,l S2 down gives you neck out of phase with bridge, and s3 gives you the neck slug coil, if you pull S2, do you then get neck and bridge in phase and does S3 then give to the screw coil?
Short of having any further brainwaves, how about, run another series of phase and resistance tests, with neck selected, four of each, with S2 and S3 down/down, up/down, down/up and up/up. S1 and S4 down in each case.
J
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Post by Raz59 on Jun 23, 2010 3:22:01 GMT -5
(I soldered the loose white wire to its lug, results are still the same) To put it mathematically plain and simple, my situation is: S2 down = neck out of phase with bridge; S2 up = neck in phase with bridge;
As for the active coil, I'm not entirely sure about the way of checking that. I'll just post the resistance values and phase orientations like you asked.
Neck humbucker selected, coils are in-phase with each other:
1. (all pp's down) DC resistance: 8,45KΩ Phase orientation: up
2. (S2 pulled) DC resistance: 8,45KΩ Phase orientation: down
3. (S3 pulled) DC resistance: 4,28 KΩ Phase orientation: up
4. (S2 and S3 pulled) DC resistance: 4,25 KΩ Phase orientation: down
And John, can you give me a sure fire way of checking which coil is active? Because tapping each coil with a screw driver isn't as conclusive as I would like it to be. When only S3 is pulled, things seem right and I seem to only get output from the screw coil (by tapping it with the screwdriver).
But when I pull S2 and S3, it seems I get equal output from both coils! Resistance-wise, only one coil is in the circuit...I don't know what to make of this. Again, I appreciate your help.
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Post by JohnH on Jun 23, 2010 7:28:09 GMT -5
Too weird! Those results are consistent with it having been OK as I first suggested, before that last green/white swap. Thats all S2 does, as wired now, it swaps green with white. So according to all 19th and 20th centrury theories of electromagnetismm relativity and quantum mechanics, if green and white were swapped back again it would be OK.
Readings 3 and 4, showing slight differneces suggest that it is bringing up the two different coils correctly
Other than tracing the wiring, I dont know a better way to identify active coils than by tapping them, but you do get a signal if you tap the other bypassed coil. Id say that the screw coil would give the clearest difference between whether it is active or not.
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Post by JohnH on Jun 24, 2010 20:41:37 GMT -5
Hi Raz – what to do next? Maybe at least it can be said that the wiring is all working correctly, except that S2 is up for in-phsae and down for oiut of phase?. Apart from that, is it all fine? It would be worh having a careful listen to all settings to see if you can find any other anomalies. How is the hum canceling now? Any pair of single coils should have less hum than one single coil, although they wont be completely hum cnacelling if they come from different pickups.
You can also check further into grounding. We know that the neck cover is not grounded (which it should preferably be) , but how about the strings, and each of the bare wires and braids inside? You can check those quickly by measuring resistance to the barrel of a jack plug on the cord to the amp.
John
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Post by Raz59 on Jun 25, 2010 6:07:40 GMT -5
The guitar is much more quieter in terms of noise to signal ratio than before, I can tell you that. I even fixed my guitar cable in the process, because the lead was oxidized and causing a lot of instability in the sound.
Yes, S2 is still inverted, perhaps I should try and invert white and green wires again? I'm almost sure I made swapped wires correctly, but it won't hurt trying it again, to see if the phase is switched.
As for the other settings: I turned my amp up until I heard the ground hum more pronounced. Humbuckers are quiet enough, compared to the single coils. Although connecting both screw coils together (assuming it's the screw coils) isn't hum cancelling at all, it's the same amount of hum from just one single coil.
I'm not at all satisfied the lack of difference that the single coils have from the humbuckers. To be honest, since my bridge is a very hot pup, I'm considering implementing phase reversal on that pickup alone and lose the single coil sound altogether...there is some significant output loss, but the sounds achieved have a bigger contrast.
I suppose the strings are grounded, because the hum gets quieter when I lay my hands on the,. And I removed the accursed cover of the neck pickup. So now I reduce the chances of ground buzz to whenever I touch the screws or slugs.
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Post by JohnH on Jun 25, 2010 6:58:41 GMT -5
Yes, S2 is still inverted, perhaps I should try and invert white and green wires again? I'm almost sure I made swapped wires correctly, but it won't hurt trying it again, to see if the phase is switched. Yes I think I would do that too if I was you It could be that the two pickups are so different that a coil from one just cant cancel hum from the other. Good luck with whatever you decide! John
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