The difference between RWRP and non RWRP

[ScottA]

I just posted this over at TheGearPage. I thought you guys might find it interesting.

There is a slight, but measurable, difference between RWRP and non RWRP.

Here's how I determined it.

I mounted a set of pickups in a pickguard, the middle pickup being RWRP. To convert the middle pickup to non RWRP, I removed it from the pickguard and flipped it over, effectively flipping both the polarity and winding direction relative to the other two pickups with everything else held exactly constant. I did not hard mount the middle pickup so I could flip it quickly, but took care to ensure that it was at the right height relative to the other two (although slight differences in height don't affect the measurement anyway). I also maintained the integrity of the pole piece location (i.e. the low E magnet stayed in the low E slot).

I measured the inductance of the bridge/middle pair wired in parallel at 1 kHz with a Extech model 380193 LCR meter. I took ten measurements in a row at each orientation in the space of about 5 minutes, changing the RWRP orientation between each measurement. With each measurement, I toggled the measurement frequency between 120 Hz and 1 kHz to reset the meter.

The RWRP inductance is 1591.97 +/- 0.63 mH
The non RWRP inductance is 1579.13 +/- 0.60 mH

This is only a difference of about 0.8% but it is statistically significant (by a pretty wide margin).

[David Schwab]

Nothing has changed on the pickup. So the difference in readings is either an error, or some other factor, such as interaction with neighboring pickups.

If turning a pickup over affects the inductance, than try it sitting on your kitchen table away from the guitar, and turn it over. Also pickups are measured in H, not mH, so the difference you see is actually very small. Either way with rounding it's 1.5H.

[ScottA]

1 mH = 0.001 H

I did a control experiment.

I measured the middle pickup alone in the assembly with the two other pickups installed.

RWRP 2711.4 +/- 0.52 mH
non RWRP 2721.3 +/- 0.48 mH

This is only about a 0.4% difference, but again statistically significant by a wide margin.

I then removed the other two pickups and measured the middle pickup in place:

RWRP orientation 2716 +/- ~0.5 mH*
non RWRP orientation 2716.7 +/- 0.48 mH

*all ten measurments on the RWRP were 2176 - 0.5 appears to be the measurement error in this inductance range using my test protocol. Also note that the meter return 4 significant digits above 2 H (in H) and 5 significant digits (in mH) below 2 H.

Note that when the other two pickups are not installed the difference between the measurements is very slight and likely attributable to the meter, and that the average of the RWRP and non RWRP measurements is the same as the measurement when the other two pickups are absent (i.e. the average of 2711 and 2721 is 2716). Also note that when measuring both pickups together, the magnitude of the affect is doubled, since the two pickups are interacting with each other and you're measuring changes to both pickups.

[ScottA]

Nothing has changed on the pickup. So the difference in readings is either an error, or some other factor, such as interaction with neighboring pickups.

If turning a pickup over affects the inductance, than try it sitting on your kitchen table away from the guitar, and turn it over. Also pickups are measured in H, not mH, so the difference you see is actually very small. Either way with rounding it's 1.5H.

That's exactly the point. The interaction with the magnetic fields of the adjacent pickups induces a measurable effect. I can rationalize that a good ear can hear a 0.8% difference in inductance.

It is also interesting to note that most people respond that they don't hear a difference on positions 1,3 & 5 where the effect is roughly halved (and probably even less than that for positions 1 and 5) vs. positions 2 and 4.

I like data. Data do not lie.

[ScottA]

Also, don't get distracted by the fact that I'm flipping the pickups over. I'm not trying to say that, by itself, inverting a pickup makes a difference.

Flipping the pickup over is simply a nice way to get the response in both RWRP and non RWRP mode with exactly the same windings and the same magnets at exactly the same strength. This yields a clean look at the effect of RWRP on the electrical response without introducing any other variables.

[copperheadroads]

did you just measured the inductance or did you do some playing ,& was there a noticeable difference in sound /tone

[ScottA]

No I didn't play it, it was upside down! A major thing that could affect the response in actual playing would be the lack of stagger on the bottom side of the pickup. I thought about pushing the magnets around when I was flipping, but I didn't want to trash the pickup. Who knows, maybe the stagger difference is that other 0.7 mH that I measured when I was flipping it without the other two pickups.

I'm not saying I could hear a 0.8% difference, I'm not even saying that I think it is something that should concern even the most die hard tone hound, but I do think it is intriguing that a difference can be measured.

I do think this is real, actually. I measured this earlier in the week, and I saw differences on the same order across the board (R,C, 120 Hz and 1kHz, etc.) but I didn't think I would be able to convince anyone that it wasn't within the measurement error (I highly doubt I still will, LOL!). I figured out a better way to do the experiment today, and that's what I report above.

I should also point out that the difference in the frequency response is negligible. The resonant frequency difference is 0.04% which is well within the measurement error, and the frequency and phase angle plots pretty much overlay. I'll try to get some pdfs of some of the plots and post then up here in the next couple of days.

[big_teee]

So cut to the chase!
Bring on the test.
What is the moral of the story.
Is this proof not to RWRP, or What.
Is this showing the difference, or is there a lesson to be learned here?
Like Copper said about playing it.
Is it going to sound better or worse, that's all a guitar picker really cares about!
Not trying to be sassy here, but tell us what we are supposed to be learning and taking away from all this pickup Flipping???
Peace,
Rock On!
Terry

[ScottA]

The point is that something can be measured to get to the bottom of one of these infernally qualitative questions that are always being bandied about.

For me, the potential of quantifying the difference is at least, if not more, important than the aural interpretation of the difference. If I can establish the quantitative difference, I can more accurately predict what the sonic difference will be.

If I was to play them and then post about one sounding "more organic" or "twangier" or "more transparent" or having more "quack" what would that prove? It isn't better or worse, its just a little different. People ask, "does RWRP make a difference in tone?" A partial answer is: it makes a difference in inductance. The implication is that, yes, theres is a quantitative basis to say it will make a difference in tone.

The moral of the story is that perhaps situations corresponding to subtle tonal variations can be measured and quantified.

This is just an example.

[copperheadroads]

my first reply to this thread ,i thought you turned around the middle pickup wires facing the neck pickup but you said you turned it upside down so the coil is not protruding through the pick guard & instead down under the the guard & with a flat pole that cannot be adjusted close enough to the strings pickup . of coarse it will sound different . but your findings are certainly interesting & something to think about & test .some night when i want to do some research ....thanks

[ScottA]

I actually did it with a pickguard removed from the guitar, and made the measurements at my desk.

In the RWRP mode the pickup was situated normally. In the non RWRP mode the pickup was basically rotated 180 degrees such that the bottom flatwork was then above the pickguard, with the lead wire connections pointing towards where the neck would be and the staggered magnets pointing down into where the pickup cavity would be. The pickup was centered with respect to the height of the other two pickups in both positions.

[copperheadroads]

interesting

[big_teee]

I actually did it with a pickguard removed from the guitar, and made the measurements at my desk.

In the RWRP mode the pickup was situated normally. In the non RWRP mode the pickup was basically rotated 180 degrees such that the bottom flatwork was then above the pickguard, with the lead wire connections pointing towards where the neck would be and the staggered magnets pointing down into where the pickup cavity would be. The pickup was centered with respect to the height of the other two pickups in both positions.

So I guess, the hypothysis is?
That's where I keep falling in the hole!
What do I take from this test?
I would think Unless you have it upright in a RWRP playable mode with the stagger on top.
With it upside down, I don't think your readings would mean much!
What do the rest of you think?
Like ^
Interesting!
Later,
Terry

[ScottA]

So I guess, the hypothysis is?
That's where I keep falling in the hole!
What do I take from this test?

The question is: is there a difference in the response of a pickup in an RWRP environment vs a non RWRP environment?

The answer is: yes.

The implication is that there is quantitative support for the observation of tonal differences between RWRP and non RWRP.

[ScottA]

I would think Unless you have it upright in a RWRP playable mode with the stagger on top.
With it upside down, I don't think your readings would mean much!

I'm measuring the test response of a component in an electro-magnetic circuit.

If you mounted an inductor on the bottom of a circuit board instead of the top and measured it, would that make the results any less valid? You might measure a difference as a function of the local environment of the top vs. the bottom, but you could still take a valid measurement.