big lot of questions

[black_labb]

basically i have a fair few questions that ive slowly been turning around in my head and want to confirm my theoretical thoughts that are based on my logic and the little knowledge i have built up from the internet.

id apreciate if i got some responses but understand if you dont want to reply or read this as it is fairly long.

firstly the basics

1. inductance > basically the amount of metal around the magnets. more coils=higher inductance metalic cores/magnets increase inductance. higher inductance will muddy up the pickup but give it higher output. am i right in saying that alnico magnets add to the inductance as they are metalic structures?

2. output> i am curious wether it is infact the higher resistance of the coil or if it is a higher surface area of the magnet wire that increases the output? im not an expert but surface area seems more probable. would a similarly designed pickup, where the only difference is the magnet wire gauge, would there be any difference other than the lower gauge (bigger wire) being warmer due to the larger coil? (thats winding to the same resistance, not coils)

3. how do magnetised poles (steel of some sort) effect the sound as opposed to rods of the magnet itself? (lets say they are both alnico 5 to keep it the same). how do they effect the output aswell as their magnetic effect on the strings?

4. if i were to make a bobbin that had the magnets where they should be, and then put a piece of wood around it, adding a few millimeters to the bobbin, but only in the direction paralell to the guitar strings (ie a 10mm by ~55mm piece of wood drilled for 5mm diameter alnico rods or philister head screws). effectively making the magnet wire almost touching the magnet on the end poles, but not the others. would this effect the sound much? would it give the e strings (standard tuning here) an increased output? or a brigher one? or is it not something i need to worry about?

5. if i made wood covers for my pickups, and then insulated the sides (but not the top) with aluminium foil or another metalic material for shielding would it effect the tone of the guitar? would it be a goodmeasure for single coils that are somewhat a mix between p90's and fender style single coils.


thanks alot for anyone willing to help out

[NightWinder]

1. inductance > basically the amount of metal around the magnets. more coils=higher inductance metalic cores/magnets increase inductance. higher inductance will muddy up the pickup but give it higher output. am i right in saying that alnico magnets add to the inductance as they are metalic structures? Yes, and also remember what ceramics do...
2. output> i am curious wether it is infact the higher resistance of the coil or if it is a higher surface area of the magnet wire that increases the output? im not an expert but surface area seems more probable. would a similarly designed pickup, where the only difference is the magnet wire gauge, would there be any difference other than the lower gauge (bigger wire) being warmer due to the larger coil? (thats winding to the same resistance, not coils) ???? Do you mean using 42 awg for say 8k, and 43 awg wound 8k? Is this correct? Your thinking 2 pickups wound to the same drc (8k example), which would be warmer? 42 will be briter than 43, thicker wire sees more highend. 43 @ 8k (example), will have a very small coil shape with a smaller field to see the strings (surface area), but at the expense of note definition in the low registers.....you can shift your frequncys very easily with a lower wind count/ thinner wire. Then you will have to combat the high end too, as this example .....you wont miss any highs. 42 will fill the bobbin more, but you should have atleast 2mm clearance from the edge of the bobbin, if not 3. You could opt for 43 heavy build, and use up some space, have a fatter coil shape, and.....I'll shut up/ Again, I'm not to sure if I understood the question correctly.
3. how do magnetised poles (steel of some sort) effect the sound as opposed to rods of the magnet itself? (lets say they are both alnico 5 to keep it the same). how do they effect the output aswell as their magnetic effect on the strings?
Steel poles are magnetized under the bobbin, giving a quite large clearence from the strings, and there is some loss of strength when you are actually transfering the magnetizum(Not from the magnet itsself, but through tranfer).
"Magnet Rods" (singles, humbucker rod mags) are a hell of a lot closer putting the magnet directly under a steel alloy string with no transfer material between the 2. You are really magnitizing the strings basically, and will happen with single coils directly. It restricts the way the string moves/ vibrates.
Logically, moving away from the strings clears it up, with less "output", closer more output, less clarity. Why? The pickup does'nt see as much material in its field, backing it off lets the string release more vibration with less power shifting the harmonic structure. Also, rod mags are much longer with a concentrated field. Thickining a bar magnet will push more power.

4. if i were to make a bobbin that had the magnets where they should be, and then put a piece of wood around it, adding a few millimeters to the bobbin, but only in the direction paralell to the guitar strings (ie a 10mm by ~55mm piece of wood drilled for 5mm diameter alnico rods or philister head screws). effectively making the magnet wire almost touching the magnet on the end poles, but not the others. would this effect the sound much? would it give the e strings (standard tuning here) an increased output? or a brigher one? or is it not something i need to worry about?
I believe you should worry more about this....Its very common. Keep the walls uniform. This is also part of some of the inconsistanceys that can give "Spinners" a bad name. Being careless . If your in the biz like me and others here, consistancey is key. No handwinds will sound exactly identical, but you can get pretty damn close between models and this could be the plague....and can shift your coil shape. Shoot for perfection, but remember your human!!!

. if i made wood covers for my pickups, and then insulated the sides (but not the top) with aluminium foil or another metalic material for shielding would it effect the tone of the guitar? would it be a goodmeasure for single coils that are somewhat a mix between p90's and fender style single coils.
I avoid any shielding like herpees.....pretty to look at, BUT I would'nt want to play with it. Seroiusly....It effects the eddy currents. Theres a really good thread here on Eddy's. My philosiphys may differ from some here, I just never liked adding any extra that really is'nt needed. Ultimately, I shoot to get the tones from the coils/proper materials, not loading the pickup down. Again, only a viewpoint...

[black_labb]

thanks alot nightwinder, that was alot of help.

you mentioned that ceramic magnets did something in relation to the inductance?

im going to go have a look at that thread about eddy currents now

[David Schwab]

1. inductance > basically the amount of metal around the magnets. more coils=higher inductance metalic cores/magnets increase inductance. higher inductance will muddy up the pickup but give it higher output. am i right in saying that alnico magnets add to the inductance as they are metalic structures?

That's correct. High inductance isn't bad, but you have to design for it. You can use less turns with high inductance designs.

Ferrite cores also affect inductance, but ceramic magnets don't seem to add too much. My first pickups were wound on ceramic magnets, and they didn't have as much output as the same number of turns on steel cores.

2. output> i am curious wether it is infact the higher resistance of the coil or if it is a higher surface area of the magnet wire that increases the output? im not an expert but surface area seems more probable. would a similarly designed pickup, where the only difference is the magnet wire gauge, would there be any difference other than the lower gauge (bigger wire) being warmer due to the larger coil? (thats winding to the same resistance, not coils)

more turns = more output... up to a point. A stronger magnet helps get the high frequencies out, since they need more energy due to impedance.

The size of the part of the magnet that has the pole also effects the strength of the magnet. So it's a bar magnet as used in humbuckers, the thicker the magnet the stronger it is.

Larger gauge wire has less resistance. Larger wire will give you more top end... but keep in mind that you can wind less of it on a given coil form. Thinner wire will have more mids and lows, but once again the smaller size of the coil can make it brighter.

Coil geometry matters. Tall thin coils sound brighter than wide squat coils. Think of Jazz bass vs. P-bass, or Strat vs. Jazzmaster pickups.

3. how do magnetised poles (steel of some sort) effect the sound as opposed to rods of the magnet itself? (lets say they are both alnico 5 to keep it the same). how do they effect the output aswell as their magnetic effect on the strings?

The steel poles will have higher inductance, and are usually powered with a ceramic magnet to make up the top end. I've swapped out the magnets in my pickups for same size alnico 5 bar magnets. The pickups have steel rails. The alnico was warmer with less top end than the ceramics.

The best thing to do is try out all the combinations!

4. if i were to make a bobbin that had the magnets where they should be, and then put a piece of wood around it, adding a few millimeters to the bobbin, but only in the direction paralell to the guitar strings (ie a 10mm by ~55mm piece of wood drilled for 5mm diameter alnico rods or philister head screws). effectively making the magnet wire almost touching the magnet on the end poles, but not the others. would this effect the sound much? would it give the e strings (standard tuning here) an increased output? or a brigher one? or is it not something i need to worry about?

It would probably change the tone somewhat... DiMarzio has some patents on similar designs that use a small spacer between the bar magnet and the poles. It softens the tone.

5. if i made wood covers for my pickups, and then insulated the sides (but not the top) with aluminium foil or another metalic material for shielding would it effect the tone of the guitar? would it be a goodmeasure for single coils that are somewhat a mix between p90's and fender style single coils.

I use both plastic and wood covers. If you use shielding on the sides, which you should, don't have the ends touch... that produces a closed loop, and can shunt some top end. I use foil, either copper or aluminum, and I also shield the top. Run the ground from the shield as a separate wire from the pickup common. I have all the metal parts grounded by this wire. The bare "bleed" wire in multi conductor cable is perfect for this.

thanks alot for anyone willing to help out

Hope I gave useful info! That's why we're here!

[David Schwab]

I avoid any shielding like herpees.....pretty to look at, BUT I would'nt want to play with it. Seroiusly....It effects the eddy currents. Theres a really good thread here on Eddy's. My philosiphys may differ from some here, I just never liked adding any extra that really is'nt needed.

That's a good point to bring up. Foil is too thin to cause any major eddy currents, but as I said, don't run a piece of foil around the coil and have the ends touch! A lot of people have done this over the years, including SRV in his guitars. You just need either a gap between the ends, or some insulation.

Another way to combat eddy currents is to break up the total surface area of the shield. If you are shielding the top face of a cover, try adding slits to the shield, or make it in two or three parts. Keep a thin gap between the parts. You can use adhesive copper foil and just cut slits in it. This keeps the eddys small.

An example of this is the aluminum shield behind strat pickguards. I mean the full size one. If the aluminum is too thick you can loose high end. You can fix this by cutting slits from the pickup openings to the edge.

Keep it thin and keep the surface area down.

[black_labb]

thanks for the help dave, i think ill start planning the pups, ive got most of the ideas but might draw some things out.