A few months ago I got a 'Vintage' SG Junior with a P100 fitted.
It sounded very soulless, so I tried it with a few alternatives.
To cut a long story short last night I decided to have a go at modding it.
The P100 is formed of two vertically stacked bobbins with two bar magnets in between them. The pole pieces pass through both coils. The coils are wired in parallel to a typical Gibson shielded lead. The bobbins are each wound with an 18k coil.
What I've done is to remove the coil on the lower the lower bobbin from the circuit. I did this by unwrapping the paper tape on the lower bobbin until I reached the black and white wires connecting to the shielded output lead. Then I simply unsoldered the lower coil.
The DC resistance of the resulting pickup is of course 18k.
It definitely sounds a lot better than the noise cancelling version, but I'm still
not sure it is really good. It's definitely amusing though. The pickup is very hot indeed - hotter even than a BKP Warpig for example. The low end is a little muddy and it has a kind of 'scorching' tone to it.
I'll leave it fitted and see if I can find a use for it.
Comments
I have also heard of wiring them with a resistor/cap network in line with the second coil, which retains most of the hum cancellation while improving the sound - http://www.blueguitar.org/new/articles/blue_gtr/gtr/lp_jr_spec_mod.pdf
I haven't tried this personally but I think it should work as described.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Pehaps the P100 design has indeed changed, there is also the Billy Armstrong version of course (which he doesn't actually use) having mismatched coils.
There is an opinion in some quarters that coil proximity can influence string excursion and the overall tone - even if one of the coils involved is not in circuit. This may be the case with the P-100 and Duncan stack designs. I suspect that it may also be true of the Duncan P-Rails model.
The comparison to a BKP Warpig is valid. I suspect that the Gibson coils have been wound on the assumption that they will be run in parallel with a second coil. Some frequency cancellation will have been anticipated.
Perhaps, the best compromise for tone and noise-cancellation would be to run the lower coil of the stack via a mini trim pot. This way, the pickup as a whole can be run with a partial coil split. Hopefully, there is a sweet spot where it sounds acceptable and rejects the worst of the hum and interference?
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
you might need to knock up a simple base plate but it should sound better.
I'm no Seth Lover, but in my experience a baseplate makes less of a difference the hotter you wind them.
Still, it'd be a quick and easy change to patch both ends of the lower coil to ground.
Another thought with a baseplate would be to insert one between the magnets and the lower coil - a bit like a DiMarzio HS-3
At the end of the day it comes down to whether having a hum-cancelling option is more or less important to you than having the true single-coil sound.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Speaking of Falbo, it will be interesting to discover the Fishman Fluence take on a P90.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein