ampage
Tube Amps / Music Electronics		 For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

 

Re: Pickup polarities...


 :
5/27/1999 7:19 AM
Liam
 Re: Pickup polarities...
To check magnet polarity with a compass just remember that opposite poles attract. Contrary to the opinions in the thread on magnet polarity making a difference, it does. It's exactly the same effect as reversing the polarity of the coil. (It's a consequence of Faraday's law in electromagnetic induction, and the geometry of the law). I believe the way the humbucking effect for SC pick-ups normally works is to use out of phase coils and out of phase magnets. Thus the signal is in phase but the coils are out of phase. As GFR says, if you're careful you should therefore be able to choose humbucking combinations in coil cut.  
 
GFR  
 
>Peter Green used a bridge pickup on the neck.  
 
That's unlikely.  
 
Early PAF's are all the same. The bridge and neck pick-ups were identical(8K coils). The out of phase and pick-up the wrong way round were the result of a mistake when the guitar was being repaired. (you can put the pickup's in either way round in a Les Paul. I actually got that "from the horses mouth", as I met Peter Green and just had to ask.  
 
Funnily enough he also said that he hated the Les Paul, and only got one because Eric Clapton had one, and he was replacing him in the Bluesbreakers. He didn't like the Strat too much either, and said his favorite current guitar was his Gibson semi (Howard Roberts fusion?), and his favorite of all time was a Harmony Meteor. Honest to God, that's what he said. (I'm not sure he's the full quid anymore, God bless him. He's an all time hero.)  
 
Liam
  
5/27/1999 10:20 AM
GFR
quote:
"Early PAF's are all the same. The bridge and neck pick-ups were identical(8K coils). "
 
 
I read that in GP magazine, I guess your source is better :)  
 
Well I can't speak for early PAFs, but here's what goes on on my guitar:  
 
The Bridge pickup from the Les Paul copy that I put on the neck position of my guitar has the adjustable poles near the bridge. The shielded cable leaves the pickup from a hole in the base plate locate near the bridge, near the tone controls.  
 
 

 
              ---------
 
              ~p~ *     ~p~
 
              ~p~ *     ~p~
 
              ~p~ *     ~p~
 
              ~p~ *     ~p~
 
              ~p~ *     ~p~
 
              ~p~ *     ~p~
 
              ---------
 
               ~p~
 
             cable
 

 
 
 
If I just took it and put it into the neck position, both pickups in the guitar would have the adjustable poles nearer to the bridge. I wanted the adjustable poles on the neck pickup to be nearer to the neck (like in a "normal" two humbucker guitar). So I rotated it.  
 
 
          --------cable
 
          ~p~          ~p~
 
          ~p~   ---------
 
          ~p~   ~p~     * ~p~
 
          ~p~   ~p~     * ~p~
 
          ~p~   ~p~     * ~p~
 
          ~p~   ~p~     * ~p~
 
          ~p~   ~p~     * ~p~
 
          ~p~   ~p~     * ~p~
 
          ~p~   ---------
 
          ~p~
 
  ---------
 
 
 
The cable had to cross the whole pickup cavity in its way to the tone controls.  
 
I don't know if this is something "wrong", but it looks good and sounds good. And blends nicely with the bridge pickup that was already hot.  
 
GFR
  
5/27/1999 10:38 PM
Steve A.
GFR:  
 
    Flipping the magnet and reversing the leads was a trick that didn't work with a humbucker at all (although I'd used it with P90's (one of them) to make them humcancelling).  
 
    So what do you think of the magnetic effect on the strings, with the magnetic polarity of the pickups staggered vs. not-staggered? For a vintage strat, the middle pickup was not RWRP so that all 3 pickups had the same magnetic polarity facing the strings. I believe that as you put a steel string in the path of a south-up magnet, the string itself picks up a "southerly" polarity. By having all 3 magnets south-up, I believe that it may have a dampening effect on the strings so that they may not resonate quite as long. If this theory is correct (not a given!) then having the middle pickup be RWRP would lessen the magnetic dampening of the strings. Or is that bass-ackwards???  
 
    So how would that apply to a LP with humbuckers? If having the polarities staggered on a strat would lessen the magnetic dampening then it seems like it would be a good idea to flip the magnet and reverse the leads for one of your humbuckers. Or maybe that is not as relevant on a LP because the two inside coils are about 3" apart.  
 
    In any case, with magnetic dampening being a factor, it is a good idea to resist the temptation to raise your pickups up until they just barely miss the strings. Back in the days of stock BF amps, you'd do that to produce the strongest signal possible to help overdrive the amp, but with high gain (or higher gain) amps you may not need that extra oomph! from the pickups.  
 
    With my set of Lindy Fralins on one of my strats I found that they really sounded a lot better when I lowered them closer to the pickguard. The high E on the neck pickup is about 3/16" from the pole piece while it is about 1/8" away from the pole piece of the bridge pickup. BTW I replaced the bridge pickup with a second middle pickup so that the bridge/neck linkages can be hum-cancelling (along with the bridge/middle linkages). So the top polarity of my pups are as follows: neck:N middle:S bridge:S. The guitar sounds great and has good sustain.  
 
Steve Ahola  
 
P.S. I tried a quasi-PRS arrangement on the coil cut switch on my 25-50 LP, and decided that having an ungrounded coil does add significant hum in a noisy environment so I'm going to rewire it with a 3PDT switch to reduce the noise since all hots will terminate in a ground through the coils.
  
5/28/1999 5:12 AM
Liam
GFR:  
 
Your pickup placing is just like a 50's Les Paul!  
 
Steve:  
 
I'd never though about the magnetic effects on string resonance (hum-cancelling vs. not), but they're likely to be pretty strong. I'd guess that hum cancelling modes are more restrictive on string movement than non hum cancelling. I've got a couple of Strats, one of which I like more than the other. I'd better go and check if one or both of them are hum-cancelling at the moment.  
 
I reckon you're on the money with the LP pickups being so far apart, and so not affecting each other too much. I always find I have to wind them down low to improve the bass response. I suppose that must be the magnetic effects damping the low frequencies.  
 
I think I'll try flipping the magnet in one pickup anyway. I'll let you know what happens!  
 
Liam
  
6/1/1999 11:24 AM
gfr
quote:
"Funnily enough he also said that he hated the Les Paul, and only got one because Eric Clapton had one, and he was replacing him in the Bluesbreakers. He didn't like the Strat too much either, and said his favorite current guitar was his Gibson semi (Howard Roberts fusion?), and his favorite of all time was a Harmony Meteor. Honest to God, that's what he said. (I'm not sure he's the full quid anymore, God bless him. He's an all time hero.)"
 
 
I've read an interview in GP magazine where he says he traded his '59 LP with Gary Moore. He said the LP was "hard to play the blues on" and the he didn't think it "was supposed to be a blues guitar". The interview featured a photo of him with a Howard Roberts Fusion and he said he used a Twin. This was in July '96.
  
6/1/1999 3:00 PM
Liam
That's around when I met him (I think it was nearer the end of '96). I got a friend to take a photo of me and Peter Green, messing with guitars! Imagine that, man. A real moment in my life!  
 
Liam
  
6/1/1999 3:19 PM
Mark Hammer
Cool when that happens, eh mate?  
 
I've had my share of such meetings (I'll forego the list), and the thrill never really goes away. Congrats.
  

<<First Page<PrevPage 2 of 2