software

Hi everybody,

I have posted a thread before about a set of Alnico 2 Pro humbuckers that were recently installed in my '92 LesPaul Classic reissue.

Here is the problem: The pickups, when selcted individually, hum exactly as if they were single coils. However, when the pickup selector is in the middle position, they stop humming. It's VERY annoying.

If I am going to use Humbuckers, I don't want some humming! That's why they're called Humbuckers!!!

The pickups (4 wire conductor) were installed by a reputable certified technician that installed many pickups.

Here is what I have tried/looked at:

1. I have opened the guitar and the wiring is done exactly as indicated in the documentation that came with the pickups (standard wiring, no coil splitting).

- Red and White wires are twisted and soldered together and taped up.
- Black wire is soldered to the hot output.
- Green cable is quot;strippedquot; and soldered to the pot (I think that is the ground)
- The bare (very thin) cable is also soldered to the pot where the green cable is.2. When both pickups are selected individually with the pickup selector, I quot;tappedquot; on both coils in the pickup and I hear a thumping sound coming out of the amplifier on both coils. So, this tells me that both coils are
working on both pickups.

Is there something that I am missing here?

I will be bringing back the guitar to the tech that installed the pickups to explain my problem to see if he can fix it.

Any suggestions?

If the tech can't fix it, I will be bringing the guitar to the store where I bought the pickups and I will ask their tech to fix it. If he can't fix it, those pickups are coming out!!!

Does make Alcnico 2 Pros with single conductor wires without going the custom shop route?

I just hope that the store where I bought the pickups from or at least will be able to replace the pickups without charging me.

Any help would be greatly appreciated.

Maybe it's not the pups that are humming? Have you tried to shield you control cavities?

wow - this is stumping ... it sure sounds as though you've checked everything ... the only thing that pops out to my eye is when you say that the green wire was 'stripped' .... i always suspect things of shorting out when there is a ground exposed .. i even put heat shrink on my bare wire to reduce the likelihood of this happening once all those wires are crumpled into that tiny cavity ...

are all the pots grounded?

did the old pups hum?

good luck
t4d

Hey guys,

Thanks for the quick replies!

Tone4days,

Before the pickup replacement, I had the stock 496R and 500T Gibson ceramic humbuckers in there and they didn't hum at all. However, they were single conductor wired pickups, not 4 counductor.I'm not sure if all of the pots are grounded. Shouldn't they be by default? I'm not even sure how to check that.

Is the green cable (ground) supposed to be stripped? I can't seem to get a clear yes/no answer on this one.

Also, do you know if the very thin bare wire (the quot;5th wirequot;) is also supposed to be soldered to the pot right where the ground cable is soldered?

I'm such a newbie at this that I feel that I'm getting screwed, just like when I take my car to the mechanic's!

Green and Bare normally get soldered together then the pair to gound. Any excess exposed conductor on the green wire could be causing you some probs. I normaly stip the very least amount of sheilding I can off of the green wire to solder together with the bare.


Originally Posted by NathanCahillGreen and Bare normally get soldered together then the pair to gound. Any excess exposed conductor on the green wire could be causing you some probs. I normaly stip the very least amount of sheilding I can off of the green wire to solder together with the bare.

I checked the green cable and there is only a little part that is stripped at the end...just enough to solder the bare wire with it on the pot.


Originally Posted by Z0S0Hey guys,
I'm not sure if all of the pots are grounded. Shouldn't they be by default? I'm not even sure how to check that.

Is the green cable (ground) supposed to be stripped? I can't seem to get a clear yes/no answer on this one.

Also, do you know if the very thin bare wire (the quot;5th wirequot;) is also supposed to be soldered to the pot right where the ground cable is soldered?

Yes the green and bare wires should be soldered to ground. In the application you are describing I would solder them together and then to whatever common grounding point I am using.

Yes all of the pots should be grounded. This can be done in various ways, either through the metal plate Gibson installs them on or via wires conecting them to ground.

You say the black is soldered to the quot;hot outputquot; Could you clarify that? They should both be going to a lug on the volume pot.

The wiring you describe is true of both neck and bridge pups?

Is the 3rd unused lug on the volume pots soldered to the pot casing?

When these pickups were installed was the metal plate Gibson uses to mount the pots removed? If it was the grounding situation has changed drastically and you may need to do some additional things.

The fact that it goes silent when both pups are on seems puzzling. Have you inspected the wiring to the switch?

Is the Bridge grounded? They typically aren't on LP's and can help but I don't think this is the issue.

This issue seems to be in the controls and not the pickups. I doubt that single conductor wire on the pups will fix the issue.

Hey Architect,

Thanks for the reply. Here are my answers.

You say the black is soldered to the quot;hot outputquot; Could you clarify that? They should both be going to a lug on the volume pot. [/QUOTE]

Yes, the black wire is soldered to the lug on the volume pot, same as the black cable in my old pickups were soldered on to.Originally Posted by TheArchitectThe wiring you describe is true of both neck and bridge pups?

Yes.Originally Posted by TheArchitectIs the 3rd unused lug on the volume pots soldered to the pot casing?

I will have to check.
Originally Posted by TheArchitectWhen these pickups were installed was the metal plate Gibson uses to mount the pots removed? If it was the grounding situation has changed drastically and you may need to do some additional things.

No, only the old pikcups were removed.Originally Posted by TheArchitectThe fact that it goes silent when both pups are on seems puzzling. Have you inspected the wiring to the switch?

No, but the tech didn't mention doing some work on the switch. It looks the same as it was before.

If you didn't install them, and paid a tech to do it, take it back to the tech and tell him that you're getting hum. The pickups should not do that. Either you got a bad set of pickups, or the tech messed up and should redo his job. I can't believe a tech would install a set of pickups and give them back to you with a hum like that. If you installed them, desolder and resolder all the grounds.

check the red/white wires
MAKE SURE they have been twisted together then soldered
if they do not have a good connection they will not cancel hum

yeah, take it back and make him fix it ... going from the stock pups to 4-wire is NOT the cause if they were installed properly - ESPECIALLY because you are not doing any splitting ... i think he just left some pots ungrounded or somesuch and they hum cancel in the middle switch position because they are phase-cancelling .. just a coincidence

it'll be fixable, dont get too worked up about it

we're here to help
cheers
t4d


Originally Posted by WICKED LESTERcheck the red/white wires
MAKE SURE they have been twisted together then soldered
if they do not have a good connection they will not cancel hum

i thought of this too, but the tap test and the fact that he is getting signal through them at all seems to point to the red/white being ok

t4d


Originally Posted by tone4daysyeah, take it back and make him fix it ... going from the stock pups to 4-wire is NOT the cause if they were installed properly - ESPECIALLY because you are not doing any splitting ... i think he just left some pots ungrounded or somesuch and they hum cancel in the middle switch position because they are phase-cancelling .. just a coincidence

it'll be fixable, dont get too worked up about it

we're here to help
cheers
t4d

well IF i am right he can do this himself and it will not cost a penny
i really suggest to check the techs work on the red/white wires
these are what makes the coils work in series and cancel hum
when he puts on both pups there is no hum making me think this maybe the prob?
when two coil tapped buckers are on together they cancel hum like two singles do


Originally Posted by WICKED LESTERwell IF i am right he can do this himself and it will not cost a penny
i really suggest to check the techs work on the red/white wires
these are what makes the coils work in series and cancel hum
when he puts on both pups there is no hum making me think this maybe the prob?
when two coil tapped buckers are on together they cancel hum like two singles do What t4d was saying is if the connection was that bad it would most likley not activate both coils. Most likely not the problem but still easily checked.

You guys are awesome!!

I truely apreciate all your replies. I will take a look at the red and white wires tonight. I have a feeling he might have just twisted both wires together and taped them, instead of soldering them together.

Thanks for the help, this forum rocks!!!


Originally Posted by Z0S0You guys are awesome!!

I truely apreciate all your replies. I will take a look at the red and white wires tonight. I have a feeling he might have just twisted both wires together and taped them, instead of soldering them together.

Thanks for the help, this forum rocks!!!

Hey bro anytime we are all a brotherhood here
many times the guys here have helped me and i love them for that!
only more than happy to return the favor!

You might just want to try this to see if it helps.

get 4 small 1-1.5quot;, or 1 6-7 inch wire

Use the wire to connect the bases of the pots

Then solder the 4th wire to the body ground, or the metal plate.

If you use one long wire make small stripped places in the plastic to solder the wire to the bases and do the same thing.

This should create another common ground/grounding loop.

Hope that's good for something!

Luke

Most humbuckers have to be placed to a specific distance from the strings so that they can cancel hum correctly. Maybe they are placed in wrong height.


Originally Posted by SozosMost humbuckers have to be placed to a specific distance from the strings so that they can cancel hum correctly. Maybe they are placed in wrong height.

hmmm, i have never read this assertion anywhere else ... and in my experiences varying pickups over the entire useful range of heights, i have never witnessed the phenomenon ... electromagnetically, i can't see why it would be true ... can you back this claim up ?

cheers
t4d


Originally Posted by SozosMost humbuckers have to be placed to a specific distance from the strings so that they can cancel hum correctly. Maybe they are placed in wrong height.