Epiphone P90
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Noodling Guitars
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Henries is the measurement for inductance. In short, it let's you know how powerful the pickup is in terms of output.
Usually manufacturers just show resistance, but the problem with that is once you throw in the variable of different gauge wire, that all goes out the window (because two equal coils can have equal resistance but differing length of wire due to different gauge). Inductance takes into account the magnet and the coil to show you the strength of the coil/magnet system to induce a current. But still, inductance itself doesn't really give you any indication of "tone" (just output). Usually the tonal characteristics in forum discussions are simply characterized based on pickups built with similar materials. You'd need to know the frequency response to know what the tone is.
Nahhh ... it's the lenght of sustain. You pluck a note and count aloud, 1 Henry, 2 Henry, 3 Henry, etc
What, 'til ya get to OH Henry. You sustain so long!!!
Noodling Guitars
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and then you feel the hunger....What, 'til ya get to OH Henry. You sustain so long!!!
... and go in OD mode (overdose)
Darkness
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And then we make a sandwich to eat while the note rings out.
After an especially long and vigorous sustain I generally like to have a smoke. 
LP_SPC_1_P90
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The only concern I have with mine being mismatched for neck & bridge P90's is that the volume knob is shared, so is the tone knob (My GC LP Special I P90 is a 2 knob shared configuration). The Neck switch position by itself is a full 1K of DCR short of what the Bridge by itself. Same holds for the middle throw position. If there is a significant enough Henries difference, the Bridge is the more dominant pickup of the 2. With the Gibson P90's, those look to be 8K P90's as a standard for both Neck & Bridge. The LP having dedicated 4 knob configurations allows one to vary the volume & tone for each. Mine is going to be whatever the pickup is blending for volume & tone sweep for less control over that.
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LP_SPC_1_P90
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The Seymour Duncans approximate more inline with the 1946 Vintage Gibson specs. DCR is 21,25 % more wire in the Bridge. They don't indicate Henries beyond a graphical lower to higher output., the Bridge is the more powerful output of the Neck & Bridge. Now I can see why Gibson has 4 knobs rather than 2 like my Epiphone has for unbalanced P90's. Epiphone IBG's have the 4 knobs like the Gibson's they are inspired by. But what is strange, the Gobson P90's are balanced for DCR at 8K.
Neck = 8.0K
Bridge = 9.7K
www.seymourduncan.com
Neck = 8.0K
Bridge = 9.7K
Vintage P90 Pickup | Seymour Duncan
Our vintage correct recreation of the 1946 Gibson single-coil with all of the midrange grittiness, sparkle, and growl that make vintage P90 pickups so special.
www.seymourduncan.com
ThreeChordWonder
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When you get to my age you skip the foreplay and just go straight to the cigarette after.After an especially long and vigorous sustain I generally like to have a smoke.
ThreeChordWonder
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The reason why neck pickups often have a lower impedance, and thus on a broadbrush, like for like, approach less output, is because the string vibration amplitudes are larger further away from the anchors (the bridge itself and your fingers or the nut). The larger amplitudes of the vibrations increase the signal output, like for like, so using a lower output neck pickup attempts to push the output back down to be closer to that of the bridge pickup.
That is where pickup heights take their full meaning.
BlueSquirrel
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I see what you mean. You can slightly adjust the difference in volume and tone either by raising or by lowering one of your pickup, but be very careful as the long screws that hold these P90 pickups are flimsy so make sure you press on the pickups' covers when you lower them.
LP_SPC_1_P90
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I was wondering if that was a possible reason, that the location of the pickup relative to the bend over points of nut or frets, & saddles produced stronger or weaker outputs ? Thus a neck pickup having a relatively larger area for the string to move might be slightly weaker. Always noticed that the method to adjust pickup height at the neck heel & pickup, that the string as fretted at the last fret and the string drops more than it does at the bridge & closer to the saddles for proximity to the pole pieces. Lower DCR might make sense ? Then again there are Strats with uniform single coils for DCR just as there are lowest, next lowest & highest DCR pickup sets for N/M/B for a Strat. May look into modding the wiring to include dedicated 4 knob configuration to have a little more control over volume & tone for each pick as individual or blended toggle positions. I can see why one would say a Gibson > Epiphone for that additional feature of controlling volume & tone, in addition to any other differences in each's LP models.
LP_SPC_1_P90
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This is more of what I was alluding & referring to, using an example. Let's say that I have a neck P90 that measures DCR 8K & Henries 3.25. The Bridge P90 is DCR 9.4K & 4.0 Henries. I may want separate & dedicated 4 knob controls to customize the output of the difference in Henries output, whether I've toggled the switch for neck only, both or even the Bridge only positions. Customizing the volume level and even tone for the respective pickup. I could set the neck pickup to full volume with max treble of clarity with the option of adjusting the volume & tone output of the Bridge to be a warmer tone and less presence for volume for being blended with the neck pickup. I mean, for Classical Strat wiring the Bridge pickup has no tone control, unless the 5 way switch is jumpered with a tone tab on the switch, under the pickguard. The Gibson/Epiphone LP isn't even like the Telecaster for the 2 vs 3 vs 4 knob wiring diagrams.
ThreeChordWonder
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As standard, current 4 knob Gibsons and Epis come with DE-pendent volumes. But you know what happens when you use the middle position of the 3-way switch: The pickups are wired together in parallel, so when both pickups are engaged, rolling down the volume of one even slightly while leaving the other fully open makes the latter much louder than its mate. Even worse, backing down just one of the volumes to zero shuts off the entire guitar.That's handy, I suppose, in a live setting, but not, perhaps for the finesse you might want in a studio.
You can change this to INDE-pendent volumes by simply swapping the pot connections. You swap the wires from the pickup with the wires to the toggle switch on their respectibmve volume pots. You have to do both pickups / pots, not just one. You have to move the tone cap connections also, otherwise the tone pots remain DE-pendent. BTDT.
Some dispute over this last point, but make sure there isn't a ground wire between the two volume pots. Wire each volume pot ground to its tone pot ground, then ground the two tone pots to each other in a sort of "C" configuration. If you wire them in a loop or "O" shape you could have problems. At best you're just wasting wire and solder. In the middle, you create a nice loop antenna for hum. And at worst you may find the controls don't work at all.
More at:
www.premierguitar.com
You can change this to INDE-pendent volumes by simply swapping the pot connections. You swap the wires from the pickup with the wires to the toggle switch on their respectibmve volume pots. You have to do both pickups / pots, not just one. You have to move the tone cap connections also, otherwise the tone pots remain DE-pendent. BTDT.
Some dispute over this last point, but make sure there isn't a ground wire between the two volume pots. Wire each volume pot ground to its tone pot ground, then ground the two tone pots to each other in a sort of "C" configuration. If you wire them in a loop or "O" shape you could have problems. At best you're just wasting wire and solder. In the middle, you create a nice loop antenna for hum. And at worst you may find the controls don't work at all.
More at:
Mod Garage: Decouple Your Les Paul’s Volume Controls
Ever been frustrated by how the two volume controls interact on a dual-humbucker axe? Here’s how to make them work independently.
www.premierguitar.com
Noodling Guitars
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Just in case there's any misunderstanding, Henries is not a direct measurement of output - and most certainly not something you can change with potentiometers. Henries is a measurement of inductance, which is dependent on the physical parameters of the coil itself (i.e. how much wire, thickness of the wire etc..), and of course the magnet (since it's making the core of the inductor - the pole pieces in this case - magnetic). Inductance has a direct correlation to output voltage (i.e. V = L*di/ dt), but what the pots/wiring do in a guitar circuit does not play into the inductor part of the circuit. Rather, what the circuit does is alter the properties after the voltage is induced from the pickup (i.e. essentially filters).
Yes, because when a string is plucked, think of it as a sine wave with uniform peaks and troughs. The general waveform is by necessity uniform for any given note (i.e. for example, the note "A" in standard tuning for western music is a wave that travels at a frequency of 440hz). What changes is the harmonics (i.e. the secondary waves) and of course how hard/soft you pluck will affect how much energy goes into that string to let the wave continue.
Now if you think of the peaks / troughs being uniform, then that means along a given string from nut to bridge of say (in the case of a Gibson scale guitar) 24.75", you can imagine that the wave will be equal repeating sections. In short, the "strongest" part will be the antinodes, and the weakest will be the nodes (since that's the 0 point). If the pickups are positioned closer to antinodes, the change in magnetic field will be larger and therefore the induced current will be stronger. Now think of the harmonics (i.e. the secondary waves) being half of this, and each order of harmonics halving that further. At some point, the neck pickup will pickup more/less of certain order of harmonics and vice versa for the bridge. I couldn't find a good visual representation of this for a Gibson scale guitar, but found one for a strat (sorry too lazy to draw):
This is also why design-wise, SGs and LPs sound different - the neck pickup placement is different. Hope this clarifies.
Equalphone
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@LP_SPC_1_P90 : Adjust the neck down to about 1/8" above the pickguard. Then adjust the bridge to match volume. That will be around 3/8" or less on the bridge. That's the best cure for a two control guitar.
Even better: Buy two concentric pots. Wire them as a volume/tone pair, one for each pickup. You still want to have the pickups balanced, but then you have a whole new raft of tones that you can blend up for the pickup pair.
Additional: Don't miss the adjustable pole pieces once the pickups are balanced. You can adjust strings for even volume too.
Even better: Buy two concentric pots. Wire them as a volume/tone pair, one for each pickup. You still want to have the pickups balanced, but then you have a whole new raft of tones that you can blend up for the pickup pair.
Additional: Don't miss the adjustable pole pieces once the pickups are balanced. You can adjust strings for even volume too.
