Electrical differences by wire gauge, practical demo.
Apr 30, 2017 1:49:41 GMT -5
diego_cl likes this

### Post by antigua on Apr 30, 2017 1:49:41 GMT -5

I finally got around to making some pickups for testing purposes. I made three singles coils, each are 8,000 turns, and each is wound with a different gauge of wire, 41, 42, and 43 AWG.

The goal is to see how the spec vary for a given wind count and different gauges of wire.

smallest wire to largest:

Using the Mojotone winding machine, I wound the 42 AWG first, and it's very much on the loose side. It took me a little time to get the tension thing down.

I had to apply careful pressure to the 41 AWG to get it to stay on the bobbin. The first time around I wound it too lose, and it just unraveled by itself. It's tricky to both make it tight, and not apply so much tension that the wire snaps.

The 43 AWG pickup came last, and I accidentally broke it with only 1,000 turns to go, so I carefully stripped the wire, twisted and soldered it, and kept going for the final 1,000 winds.

These bobbins and magnets are Chinese Donlis DS53 with AlNiCo 5 pole pieces. I removed the stock coil wire in order to wind my own coils in their place.

Here are the measured specs:

DC Resistance: 5.0k ohms

Inductance: 2.376H

Resonant peak: dV: 16.3dB f: 7.54kHz

Loaded peak: dV: 7.2dB f: 3.94kHz (470pF & 200k)

Calculated Cap: 178pF (188-10)

Coil width: 0.47"

DC Resistance: 6.1k ohms

Inductance: 2.365H

Resonant peak: dV: 16.3dB f: 10.7kHz

Loaded peak: dV: 7.2dB f: 4.17kHz (470pF & 200k)

Calculated Cap: 84pF (94-10)

Coil width: 0.62"

DC Resistance: 7.9k ohms

Inductance: 2.341H

Resonant peak: dV: 18.5dB f: 9.70kHz

Loaded peak: dV: 8.1dB f: 4.17kHz (470pF & 200k)

Calculated Cap: 105pF (115-10)

Coil width: 0.77"

The 42 and 43 AWG showed similar Q factors, but the 41 AWG showed a higher Q factor, which might be a result of the lower DC resistance enabling stronger resonance, but then you'd think the higher resistance 43 AWG would show a lower Q, so I don't know.

The theory says that the thicker 41 AWG should show a higher capacitance, because larger wire = more surface area, and sure enough at 178pF it is quite high. The 43 AWG is conversely low at 105pF. Both of these coils are more tightly wound than the 42 AWG coil. Had the 42 AWG been wound with the same tension, I suspect it would land somewhere in between the two, and I'll explore this more with the next experiment.

The most informative thing about this experiment for me, is satisfying curiosity about how the DC resistance of 42 and 43 AWG compare, so if a Tele neck pickup is wound to 7.5k with 43AWG, that means it's comparable to a Strat pickup with a DC resistant around 5.6k, all other things being equal.

The other informative aspect is show the strong correlation between wind count and inductance, and that the variation in coil size, the fact that the 41 AWG coil is so large and the 43 AWG coil so small, doesn't greatly impact the inductance.

To convert 42 AWG to 43 AWG equivalent, you multiply the resistance by 1.29 ( 2143 / 1659 )

To convert 42 AWG to 44 AWG equivalent, you multiply the resistance by 1.56 ( 2593 / 1659 )

To convert 43 AWG to 42 AWG equivalent, you multiply the resistance by 0.77 ( 1659 / 2143 )

To convert 43 AWG to 44 AWG equivalent, you multiply the resistance by 1.21 ( 2593 / 2143 )

To convert 44 AWG to 42 AWG equivalent, you multiply the resistance by 0.64 ( 1659 / 2593 )

To convert 44 AWG to 43 AWG equivalent, you multiply the resistance by 0.83 ( 2143 / 2593 )

The goal is to see how the spec vary for a given wind count and different gauges of wire.

smallest wire to largest:

Using the Mojotone winding machine, I wound the 42 AWG first, and it's very much on the loose side. It took me a little time to get the tension thing down.

I had to apply careful pressure to the 41 AWG to get it to stay on the bobbin. The first time around I wound it too lose, and it just unraveled by itself. It's tricky to both make it tight, and not apply so much tension that the wire snaps.

The 43 AWG pickup came last, and I accidentally broke it with only 1,000 turns to go, so I carefully stripped the wire, twisted and soldered it, and kept going for the final 1,000 winds.

These bobbins and magnets are Chinese Donlis DS53 with AlNiCo 5 pole pieces. I removed the stock coil wire in order to wind my own coils in their place.

Here are the measured specs:

**8000 turns 41 AWG**DC Resistance: 5.0k ohms

Inductance: 2.376H

Resonant peak: dV: 16.3dB f: 7.54kHz

Loaded peak: dV: 7.2dB f: 3.94kHz (470pF & 200k)

Calculated Cap: 178pF (188-10)

Coil width: 0.47"

**8000 turns 42 AWG**DC Resistance: 6.1k ohms

Inductance: 2.365H

Resonant peak: dV: 16.3dB f: 10.7kHz

Loaded peak: dV: 7.2dB f: 4.17kHz (470pF & 200k)

Calculated Cap: 84pF (94-10)

Coil width: 0.62"

**8000 turns 43 AWG**DC Resistance: 7.9k ohms

Inductance: 2.341H

Resonant peak: dV: 18.5dB f: 9.70kHz

Loaded peak: dV: 8.1dB f: 4.17kHz (470pF & 200k)

Calculated Cap: 105pF (115-10)

Coil width: 0.77"

**DC resistance observations:**8,000 turns of 42 AWG ends up at 6.1k, which is an extremely common DC resistance for Strat pickups. Without having applied much tension, the bobbin is just about maxed out at this wind count. 41 AWG resulted in a 1k drop in resistance to 5.0k, while the thinner 43 AWG resulted in nearly a 2k increase in resistance, to 7.9k ohms.The 42 and 43 AWG showed similar Q factors, but the 41 AWG showed a higher Q factor, which might be a result of the lower DC resistance enabling stronger resonance, but then you'd think the higher resistance 43 AWG would show a lower Q, so I don't know.

**Inductance observations:**The inductances are remarkably close, which is a little surprising to me, since the sizes of the coils ended up being rather different. It shows the strong correlation between wind count and inductance. Each shows only a few millihenries difference.**Capacitance observations:**So the 42 AWG has very low capacitance at 85pF, but I'm certain this owes to the rediculous looseness of the coil. When I press it with my fingers, it feels like a pillow. I'm going to wind a couple more 42 AWG coils with a focus on tension and coil thickness in order to see what the boundaries are between capacitance and coil size, for a given wind count. This surely comes close to representing the low end. Most "high quality" hand wound boutiques tent to land around 95pF, give or take 10pF, while machine wound pickups with very tight coils end up around 135pF, give or take 15pF. A note about scatter winding, I made zero effort to scatter the wire. I pretty much held the wire still, moving it around occasionally to balance out the coil.The theory says that the thicker 41 AWG should show a higher capacitance, because larger wire = more surface area, and sure enough at 178pF it is quite high. The 43 AWG is conversely low at 105pF. Both of these coils are more tightly wound than the 42 AWG coil. Had the 42 AWG been wound with the same tension, I suspect it would land somewhere in between the two, and I'll explore this more with the next experiment.

**Resonant peak observations:**The wide variation on capacitance caused the unloaded peaks to vary by over 1kHz, but with a capacitive load, the similar inductance of all three causes the resonant peaks to come rather close together, around 4kHz.The most informative thing about this experiment for me, is satisfying curiosity about how the DC resistance of 42 and 43 AWG compare, so if a Tele neck pickup is wound to 7.5k with 43AWG, that means it's comparable to a Strat pickup with a DC resistant around 5.6k, all other things being equal.

The other informative aspect is show the strong correlation between wind count and inductance, and that the variation in coil size, the fact that the 41 AWG coil is so large and the 43 AWG coil so small, doesn't greatly impact the inductance.

**Reference for DC resistance equivalence:**To convert 42 AWG to 43 AWG equivalent, you multiply the resistance by 1.29 ( 2143 / 1659 )

To convert 42 AWG to 44 AWG equivalent, you multiply the resistance by 1.56 ( 2593 / 1659 )

To convert 43 AWG to 42 AWG equivalent, you multiply the resistance by 0.77 ( 1659 / 2143 )

To convert 43 AWG to 44 AWG equivalent, you multiply the resistance by 1.21 ( 2593 / 2143 )

To convert 44 AWG to 42 AWG equivalent, you multiply the resistance by 0.64 ( 1659 / 2593 )

To convert 44 AWG to 43 AWG equivalent, you multiply the resistance by 0.83 ( 2143 / 2593 )