2 P90's - pick up height and other general questions
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heatmiser
mr. green christmas
Well, that was interesting!
With all of this in mind, I just rocked out a little while raising and lowering both PUs and checking levels and tones in all 3 positions along the way. It does make more of a difference than I thought in both areas.
I think I have it closer to the way it used be set up as the mid position tone is now closer to the way it used to be when I liked it so much.
The problem is, to get that combo tone, I have the bridge PU very high and the neck fairly low, so the volume levels of each setting are kind of screwed up...Bridge position is super loud compared with the others. I think that's why I fiddled with it in the first place? Seems like, as it is with many things, there needs to be a compromise - in this case between consistent levels and the tone I want. Not sure I can have it all...
With all of this in mind, I just rocked out a little while raising and lowering both PUs and checking levels and tones in all 3 positions along the way. It does make more of a difference than I thought in both areas.
I think I have it closer to the way it used be set up as the mid position tone is now closer to the way it used to be when I liked it so much.
The problem is, to get that combo tone, I have the bridge PU very high and the neck fairly low, so the volume levels of each setting are kind of screwed up...Bridge position is super loud compared with the others. I think that's why I fiddled with it in the first place? Seems like, as it is with many things, there needs to be a compromise - in this case between consistent levels and the tone I want. Not sure I can have it all...
ashcat_lt
Well-known member
Most of the 101 on your questions has been covered, with some pretty good follow up.
There is a little more to this question, though:
Combining two pickups in parallel (the way most folks do) raises the cutoff frequency of that filter. If both pickups are exactly the same you'd expect the cutoff to be an octave higher than either separately. In practice they're usually not exactly the same, so it's not quite an octave, but it will always be noticeably brighter.
On top of that, they kind of divide down each other's broadband output, mixing in such a way that they are both contributing less than their "full alone" volume. There is some phase cancellation of various overtones as mentioned above, but also just general attenuation. Overall it usually works out to be about the same as one of the pickups alone, almost like they're averaging out. There shouldn't be a real significant drop in volume in the middle position. If there was, I might start to suspect that the pickups were "out of phase" in the sense of opposite absolute polarity.
The old Teisco, Del Ray, and other Korean built paddles in the 70s, as well as many Danelectros, have the pickups wired in series with one another. This does basically the opposite. The output of the middle postion is both louder (almost twice as loud) and darker (almost an octave lower) than either individual pickup for exactly the same reason that HBs are generally louder and darker than SCs. There are still the overtone cancellations there, but it still adds up to more, darker output. The N*B series connection is really pretty mean and crunchy, and I strongly suggest trying it if you get the chance.
There is a little more to this question, though:
The pickups are not exactly just perfect generators. They are also highly resistive, heavily inductive, and slightly capacitive and they are connected to several loads both resistive and capacitive before we ever hear them. Basically that means that the pickups, controls, cable and [amp or pedal or whatever] input act to create one big complex low pass filter.
Combining two pickups in parallel (the way most folks do) raises the cutoff frequency of that filter. If both pickups are exactly the same you'd expect the cutoff to be an octave higher than either separately. In practice they're usually not exactly the same, so it's not quite an octave, but it will always be noticeably brighter.
On top of that, they kind of divide down each other's broadband output, mixing in such a way that they are both contributing less than their "full alone" volume. There is some phase cancellation of various overtones as mentioned above, but also just general attenuation. Overall it usually works out to be about the same as one of the pickups alone, almost like they're averaging out. There shouldn't be a real significant drop in volume in the middle position. If there was, I might start to suspect that the pickups were "out of phase" in the sense of opposite absolute polarity.
The old Teisco, Del Ray, and other Korean built paddles in the 70s, as well as many Danelectros, have the pickups wired in series with one another. This does basically the opposite. The output of the middle postion is both louder (almost twice as loud) and darker (almost an octave lower) than either individual pickup for exactly the same reason that HBs are generally louder and darker than SCs. There are still the overtone cancellations there, but it still adds up to more, darker output. The N*B series connection is really pretty mean and crunchy, and I strongly suggest trying it if you get the chance.
The SG's are are a very playable instrument. When you first pick one up, the lack of weight is really striking, and you can have your doubts about the quality as they appear fairly rudimentary.
But after playing one for a while, I have a lot of respect for them and really admire the tone. The middle pickup selector for Jazz is extremely smooth and rich.
As your your questions:
1. The magnetic field strength drops off as the inverse of the distance cubed.
That shows pretty much what you have. Your strings alter the magnetic field at the end, and that induces a current in the coil which is then amplified.
So things stay pretty loud the closer you are to the coil, but unlike a normal potential system like gravity or electric fields, the distance has a much more pronounced effect on field strength.
2. You could use PU heights to merge the sounds of the pickups equally. A difference in volume in the middle position can be due to a number of things, the number of winds around the magnet making one 'hotter' then the other, or the balance between the two has not been thought out (the neck position has a lot more disturbance because the string vibration at that point has a larger amplitude).
But in this case, I suspect your magnets in your pickups maybe starting to fade because it is a vintage guitar.
3. As a guitar gets older, the magnets in the pickups lose their 'mojo'. Literally, the strength of the magnet decreases over time as the magnetic domains within each bar reallocate, particularly guitars from the 1950's and 1960's. This sometimes has a good effect depending on the instrument. Vintage stratocaster's do it as well.
You can re-magnetize pickups, but because of the vintage status of the guitar, do not do that.
You can play with heights, and if that does not work, just grab another P90 'new vintage' pickup of the same type, and keep the original in the case when you go to sell it, and let the next owner know why you changed it.
More information here:
P90 magnet questions
Good luck.
But after playing one for a while, I have a lot of respect for them and really admire the tone. The middle pickup selector for Jazz is extremely smooth and rich.
As your your questions:
1. The magnetic field strength drops off as the inverse of the distance cubed.
That shows pretty much what you have. Your strings alter the magnetic field at the end, and that induces a current in the coil which is then amplified.
So things stay pretty loud the closer you are to the coil, but unlike a normal potential system like gravity or electric fields, the distance has a much more pronounced effect on field strength.
2. You could use PU heights to merge the sounds of the pickups equally. A difference in volume in the middle position can be due to a number of things, the number of winds around the magnet making one 'hotter' then the other, or the balance between the two has not been thought out (the neck position has a lot more disturbance because the string vibration at that point has a larger amplitude).
But in this case, I suspect your magnets in your pickups maybe starting to fade because it is a vintage guitar.
3. As a guitar gets older, the magnets in the pickups lose their 'mojo'. Literally, the strength of the magnet decreases over time as the magnetic domains within each bar reallocate, particularly guitars from the 1950's and 1960's. This sometimes has a good effect depending on the instrument. Vintage stratocaster's do it as well.
You can re-magnetize pickups, but because of the vintage status of the guitar, do not do that.
You can play with heights, and if that does not work, just grab another P90 'new vintage' pickup of the same type, and keep the original in the case when you go to sell it, and let the next owner know why you changed it.
More information here:
P90 magnet questions
Good luck.
heatmiser
mr. green christmas
achcat - Very interesting, thanks! Some of that is over my head, but I get the gist of what you're saying.
The thing is, if I fiddle with the height of the 2 PUs alone, I can solve the volume disparity issue pretty well. If I lower the bridge PU and/or raise the neck PU, I can get the output from all 3 positions to be pretty similar.
In order to get the tone I really like out of the middle position though, I find that I need to raise the bridge PU so high that it's output is noticeably higher than either the neck PU alone, or the two together...make sense? That's where I think I may have to decide to either have 3 separate tones I love, with one being a little too loud, or compromising a little on tone and having the output of each setting more similar.
In no configuration I've tried so far is the middle position substantially lower than both PUs separately, it's either all 3 at similar volume, or the neck and the middle position at similar volume, while the bridge is screaming...
May I ask exactly what this refers to? The N*B series connection is really pretty mean and crunchy, and I strongly suggest trying it if you get the chance.
(Sorry!)
The thing is, if I fiddle with the height of the 2 PUs alone, I can solve the volume disparity issue pretty well. If I lower the bridge PU and/or raise the neck PU, I can get the output from all 3 positions to be pretty similar.
In order to get the tone I really like out of the middle position though, I find that I need to raise the bridge PU so high that it's output is noticeably higher than either the neck PU alone, or the two together...make sense? That's where I think I may have to decide to either have 3 separate tones I love, with one being a little too loud, or compromising a little on tone and having the output of each setting more similar.
In no configuration I've tried so far is the middle position substantially lower than both PUs separately, it's either all 3 at similar volume, or the neck and the middle position at similar volume, while the bridge is screaming...
May I ask exactly what this refers to? The N*B series connection is really pretty mean and crunchy, and I strongly suggest trying it if you get the chance.
(Sorry!)
heatmiser
mr. green christmas
Meclazine - Thanks for all of that.
Yes, I love SGs. Always wanted one as a kid. Aesthetically, they are the best to my eye. I bought this one back in 1990 or so, so I'm pretty familiar with it, but have never needed to understand the inner workings and as such am fairly ignorant.
It may be that the bridge PU is losing magnetic mojo, as that seems to be the one that always needs adjusting and also seems to have the biggest impact on the other two settings. I'm not sure. I hesitate to change anything about the instrument due to it's age and potential value, but I also never plan to sell it, so...I'm going to keep experimenting with PU height for now. Since I don't play live, but only record here at home, having the bridge PU a good deal louder than the other two isn't a huge drawback I guess.
I mean, I normally don't switch PUs in the middle of laying down a single guitar track (where the sudden jump or decline in volume would be problematic), although sometimes during a solo, it's nice to flip that selector to change tone slightly at a key moment or whatever...
Yes, I love SGs. Always wanted one as a kid. Aesthetically, they are the best to my eye. I bought this one back in 1990 or so, so I'm pretty familiar with it, but have never needed to understand the inner workings and as such am fairly ignorant.
It may be that the bridge PU is losing magnetic mojo, as that seems to be the one that always needs adjusting and also seems to have the biggest impact on the other two settings. I'm not sure. I hesitate to change anything about the instrument due to it's age and potential value, but I also never plan to sell it, so...I'm going to keep experimenting with PU height for now. Since I don't play live, but only record here at home, having the bridge PU a good deal louder than the other two isn't a huge drawback I guess.
I mean, I normally don't switch PUs in the middle of laying down a single guitar track (where the sudden jump or decline in volume would be problematic), although sometimes during a solo, it's nice to flip that selector to change tone slightly at a key moment or whatever...
ashcat_lt
Well-known member
Yep, it's up to you. It almost makes sense to me that the bridge pickup be louder, since it's maybe a bit more likely to be used for leads.
By that I'm talking about wiring the neck and bridge pups in series with one another like I described in that post. It's common in old cheap guitars, and is also the 4th position on the Tele Baja switch. It's a pretty easy mod to add, and really rocks in certain situations. It's exactly like having a humbucker with the coils spaced very far apart.
heatmiser
mr. green christmas
The volume jump is a little extreme, but you make a good point there.
Ok, I get it - thanks a bunch for taking the time to provide all of that info man!
antichef
pornk rock
Would you recommend adding a DPDT switch like this article appears to be advising in the first diagram that shows series wiring? 3 Mods for 3 Guitars - Premier Guitar
(the beauty of working with a clone is that you don't worry about putting new holes in it
)
ashcat_lt
Well-known member
That will work, but it will leave a dead position on your normal toggle. In series mode it will be series-series-dead. If you have that one pickup selected when you switch to series mode, or flip to that pickup (intentionally or otherwise) while in series mode, you'll get nothing from the pickups and all the noise you'd expect from leaving the cable open.
I'd suggest a "series override" switch like this:
When you flip this one to series mode the 3-way ceases to function at all. The idea being that if you've chosen series mode you must want to hear both pickups, right?
Me, I'd probably put in a 4-way rotary instead because I hate the Gibson style toggles.
I'd suggest a "series override" switch like this:
When you flip this one to series mode the 3-way ceases to function at all. The idea being that if you've chosen series mode you must want to hear both pickups, right?
Me, I'd probably put in a 4-way rotary instead because I hate the Gibson style toggles.
fritsthegirl
Taste of home
Very interesting thread. I think I'd better get my flatmate to hide all the screw drivers in the house. 
Anfontan
Banned by eurt
The P-90 pickups will give a much better tone if you adjust the pole pieces closer to the strings rather than raising or lowering the pickups themselves. I adjusted the polepieces on my Melody Maker with a Gibson P-90 and the results are great!
By the way, the Gibson/Epiphone forum is a good source for these pickup and modding issues-check them out.
Tony
By the way, the Gibson/Epiphone forum is a good source for these pickup and modding issues-check them out.
Tony
Nebakanezer
New member
This has turned out to be very interesting. Heat, I have a TV yellow Les Paul Special double cut away re issue (you can partially see it in the guitar stand of my garage photo). When I bought it, it had a EMG active P90 in the bridge (the 1st owner was into playing heavy drop tuning stuff) and the factory in the neck. Anyway, I found a DiMarzio pickup to temporarily replace it. I feel I'm in the same boat, but I know that tonally it's because of the 2 brands not meshing well, or at least to my liking.I also don't really switch positions in the middle of songs, so I've got it in a good enough for now state. I know you aren't thinking about replacing your pickups, but I plan on getting some Lindy Fralin noise cancelling pickups for mine. With some of the stuff Ashcat suggested, I think you could use a push/pull pot to make those mods work. I have a G&L tele with their version of the P90's and the transitions between all positions has much more cohesiveness, but I'm thinking about the 4 position switch mod for it because a lot of times I can't leave well enough alone.
dervish riff
New member
A couple years ago, I put a 4 way switch into a MIM Tele, the series setting sounded a lot like parallel p90s. Now I have one of the Epi LP Special p90's--the first mod will probably be the push-pull series switch.