I need technical help please!

[Mike M]

Hello,

I just finished a guitar project last night and after installing the electronic I noticed that there are issues with my neck pickup. I am unsure if it is a bad pot or pickup. The pickup is a 59 Neck pickup. The bridge is a CS model of some sort. The bridge only position sounds fine and the neck only position sounds fine. But when in the middle position the tone is very nasaly and lower output than one pickup alone. Also, when in the middle position when you turn the neck pickup volume pot to fully on to 10 the volume cuts out a little and that is when the nasal tone starts to occur. If you roll the pot back a nothch or two, the volume increases and the nasal tone goes away. The neck pickup has been spliced somewhere through the years and I tried reversing the connections, but that resulted in no output form the pickup. ANy ideas for me to try? What should I do?

Thanks

 

[jeremy]

Re: I need technical help please!

it sounds like things are out of phase.

what wires are coming out of both pups?

 

[ParameterMan]

Re: I need technical help please!

You've accidently installed the Peter Green mod. Congratulations! The pickups are out of phase in the middle postion, resulting in frequency cancellation when the pickups are both at the same volume level. Some people do this on purpose, and like that sound.

It *should* be correctable by reversing the hot and cold wires from either of the pickups, or by flipping one of the magnets. Telling Jeremy what wires are going where is your best bet.

 

[Mike M]

Re: I need technical help please!

On the bridge pickup, it is standard two conductor vintage wiring soldered in the standard fashion. The neck pickup which is spliced, is wired with the inner wire soldered to the nceck pot lug and the other wire is soldered to the mesh outer wire and then soldered to the top of a pot which is grounded.

Any ideas? Why does the pickup go no output when tose wire are reversed.

Any clues why the pots changes tone as the volume is increased to the max setting?

Thanks

 

[octavedoctor]

Re: I need technical help please!

On the bridge pickup, it is standard two conductor vintage wiring soldered in the standard fashion. The neck pickup which is spliced, is wired with the inner wire soldered to the nceck pot lug and the other wire is soldered to the mesh outer wire and then soldered to the top of a pot which is grounded.

Any ideas? Why does the pickup go no output when tose wire are reversed.

Any clues why the pots changes tone as the volume is increased to the max setting?

Thanks

Probably because reversing the wires shorts the signal wire to earth.

Your best way out of this is to open the pickup and splice new cable on to it after mapping the polarity. There is a post from me detailing this process from a few weeks back.

Allparts can provide you with shielded vintage cloth bound wire.

http://www.allparts.com/categories.php?cat_id=552&cat_name=WIRE

BTW, my friend used to share a flat with Gary Moore and has played the Peter Green Les Paul. As i understand it the pickups are not reversed polarity, but the magnet is flipped in one so that instead of being north-south-north-south the magnetic polarity is flipped so that they are aligned south-north-north-south.

Or something like that...

 

[ParameterMan]

Re: I need technical help please!

BTW, my friend used to share a flat with Gary Moore and has played the Peter Green Les Paul. As i understand it the pickups are not reversed polarity, but the magnet is flipped in one so that instead of being north-south-north-south the magnetic polarity is flipped so that they are aligned south-north-north-south.

Or something like that...

One way, with the magnetically reversed pickup, current flows in opposite directions through the pickups and they're both connected normally. The other way, current flows the same way in both pickups, but one is connected in reverse. The end result is a 180 degree out-of-phase signal coming from one pickup. Hence, the frequencies that are the same amplitude get cancelled out. That's why the effect is the most noticable with both pickups full-on.

In this case, though, it IS the Peter Green mod. Both 2 conductor pickups are wired correctly, but the result is out of phase. I would be willing to bet that the CS bridge pickup has the magnet in "backwards".

The solution is to untape one pickup and:
1) Reverse the little wires going into the pickup lead from the coils.(if it's the neck, you could just remove the old lead and start over like octavedoctor suggested.) Leave the two little wires between the coils that are connected together alone.
2) Loosen the little screws on the bottom of the pickup that hold the coils in place, and use a screwdriver to push the bar magnet out. Flip it over, and stick it back in.

If I missed something, someone will straighten me out here.

 

[Mike M]

Re: I need technical help please!

Thanks for the info. So you think I should just cut the pickup wire very close the the actual pickup and solder new wires from that point. can I just use two seperate wires from that point or do I have to get the vintage wire? I should at that point be able to swap the wires to get it back to in pahse?

Thanks

 

[octavedoctor]

Re: I need technical help please!

One way, with the magnetically reversed pickup, current flows in opposite directions through the pickups and they're both connected normally. The other way, current flows the same way in both pickups, but one is connected in reverse. The end result is a 180 degree out-of-phase signal coming from one pickup. Hence, the frequencies that are the same amplitude get cancelled out. That's why the effect is the most noticable with both pickups full-on.

In this case, though, it IS the Peter Green mod. Both 2 conductor pickups are wired correctly, but the result is out of phase. I would be willing to bet that the CS bridge pickup has the magnet in "backwards".

The solution is to untape one pickup and:
1) Reverse the little wires going into the pickup lead from the coils.(if it's the neck, you could just remove the old lead and start over like octavedoctor suggested.) Leave the two little wires between the coils that are connected together alone.
2) Loosen the little screws on the bottom of the pickup that hold the coils in place, and use a screwdriver to push the bar magnet out. Flip it over, and stick it back in.

If I missed something, someone will straighten me out here.

That'd be the way to go.

the loss of siganl when the wires are reversed though points to the signal wire being connectd to something which is shorting to earth so i think it's important to establish the electrical and magnetic polarities before connecting the output cable.

I think you need to go into the pickup and establish which way the meter kicks when you tap the pickup with something iron-bearing. Whichever way the CS kicks the meter when the pickup is tapped with an allen wrench or similar is the way the other should deflect when it is tapped.

This procedure allows you to establish which of the wires from the coil bobbin goes to the baseplate of the pickup and which goes to the signal wire of the output cable. The braid of the output cable goes to the baseplate as well. This is why you can't just swap the wires at the splice. The one which you are trying to make the signal wire may be going to the base plate and this will be linked to the braid of the output cable resulting in a short to earth. If you follow this procedure the magnetic orientation of the pickups doesn't matter that much, because as long as the pickups have the same pulse polarity they will sound ok together, although there will be a subtle difference if the relative orientation is reversed.

 

[ParameterMan]

Re: I need technical help please!

I think the negative wire from the pickup is connected to the ground inside the pickup where it ties into to the 2-conductor lead. So, you'll need to open it up. If it's not a covered pickup, it's easy to unwrap the black tape that goes around the pickup. Once it's off you should be able to see the two bobbins, also with tape around them.

Stop here and look for the two wires that tie into the lead that comes out of one corner of the baseplate. You may have to remove electrical tape or shrinkwrap from the junction. The braided shield will be soldered to one wire, and also the baseplate. That's your new hot. The other wire is your new ground. You can now de-solder the lead and either replace it with a new one, or just use two wires. If you don't use a shielded lead, you may notice a bit more hum in that position.

If you do, solder it back in, connecting the braid up to the baseplate like the old one, but tying it into the internal pickup wire that used to be soldered to the inner conductor. Then tie the new inner conductor to the internal wire that used to be attached to the braid.

*EDIT* octavedoctor is right. It may be internally reversed already. It wouldn't hurt to replace the cable normally and test it before swapping things.

octavedoctor's post. I don't think you'll need it, but it's good stuff anyway. https://forum.seymourduncan.com/showpost.php?p=738613&postcount=17