Pickup resistance survey

cooperman · Post by **cooperman** » Fri May 23, 2003 12:19 am

I propose to do a survey of Hi-gain and toaster pickup resistance. I invite people to contribute by measuring the resistance of their pickups and e-mailing me the results directly. I need to know, pickup type, i.e. toaster or high gain, pickup position, i.e. bridge, neck or middle, model, serial number and finally any comments about the way it sounds. The neck pickup resistance can be measured from the output socket by switching to neck pickup only and setting the mix control to full neck. The bridge pickup can be measured setting the mix control the other way unless your guitar has the 4n7 cap that was fitted to vintage guitars. If this is the case the resistance must be measured directly accross the pickup lead. I will publish the results on the forum when complete. Thankyou in advance for any contributions.

johnhall · Post by **johnhall** » Fri May 23, 2003 10:22 am

I'm not really sure how much this is going to tell you. Between some cheap ohm meters and the interaction between the rest of the circuit, this number is probably going to vary at least plus or minus 2K.

admin · Post by **admin** » Fri May 23, 2003 11:05 am

I have wondered about the accuracy of measurements in such an endeavour. I think that some general trends might be identified providing that the manner in which the measurements are taken is consistent.

We ran into this difficulty in a previous poll. My question would be, how should these measurements be taken to insure accuracy and what should the voltmeter standard be?

rick12dr · Post by **rick12dr** » Fri May 23, 2003 1:01 pm

Peter;
Exactly.And as JH, said, interaction w/ rest of circuit.I understand some guys do Not want to go Un soldering Anything if they don't have to, but if you are a chronic tinkerer as I and others here are, you just unsolder the PU leads at the switch and get your readings.Maybe[?] better yet, unsolder the wire At the PU so there is no interaction from the PU lead wire itself. Also, what kind of meter do you guys out there have? Probably many of us have basic functional ones we got at Radio Shack and don't have much invested in.[Are your batteries still good in yours??] Yet another area to cover.....

360dave · Post by **360dave** » Fri May 23, 2003 2:30 pm

Ahhh yesss.....more electrical stuff. I did some tests to settle this question....
I have a vintage 360 that was originally wired like the 4 control, 2 pup, mono schematic on the RIC website. Because my instrument is a 60' vintage it also has the .0047 ceramic cap in series with the bridge pup. I removed this cap for this test. More modern instruments don't have this cap.
Here is how I did it.
I used a Fluke 75 autoranging digital multimeter....oh, I know how to use it too.

There are 2 ways to do this...
1. position volume controls to maximum volume
2. tone control position does not matter
3. plug in your guitar cord...hopefully a good one!
4. select neck pup with switch
5. connect meter across other end of cord
6. read meter
7. select bridge pup with switch
8. repeat 1, 2, 3, 5, 6 above

This is an inaccurate reading of the neck pup winding because the meter is also reading from the wiper of the tone pot back through ground and into the neck pup the 'back' way. This is really a parallel reading.

Here is the second and accurate method of measuring your pups.
1. unsolder the pup wire from the switch
2. leave the ground braid connected
3. connect the meter to pup wire and measure

Based on experiments with my instrument, owners of 2 PICKUP, 4 CONTROL MONO instruments WITHOUT the .0047 tone cap in series with the bridge pup MAY use the first method and ADD 500 ohms to the reading and you will be pretty close to the true resistance of the pup.
In other words, my bridge pup is 7,700 ohms using the first method. The same pup is 8,200 ohms using the second and most accurate method.

I agree with John, Peter and Don that this endeavour is difficult to get accurate readings due to the many different configurations of instrument wiring used over the years and the ability of some folks to do this properly. I realize that not everyone has an interest in the electrical part of these instruments so considering that I decided to put all of you to sleep with this long winded post. Also, I suspect that there may be many more individuals out there who are electrically inclined and are into many different collections of quarks.
There is just something about the person that is into electric guitars, radio controlled airplanes, amateur radio and high speed optical data transmission.
They are probably a retentive weirdo like me.

rick12dr · Post by **rick12dr** » Fri May 23, 2003 3:21 pm

There is just something about the person that is into electric guitars, radio controlled airplanes, amateur radio and high speed optical data transmission.
They are probably a retentive weirdo like me.

I'm decidedly Not an electronics whiz; I know enough to get and keep all my guitars in working order[don't ask me about active electronics!!]
"Retentive weirdo"...hmm, wish I'd had that term to use back in high school 30 some years ago when all this stuff began...

360dave · Post by **360dave** » Fri May 23, 2003 4:14 pm

Hi Don....yeah, that IS a 10 cent term in use these days. Back when I was in High School when I got this guitar, descriptive terms in use tended to be limited to 4 letters....sometimes 10 or 12 except the crowd I ran with couldn't read more than 6 or 7 letters in a row.
Now that I guess I am retired, I have almost nothing to do except take care of the seemingly never-ending projects of all sizes and descriptions.
This was one of them.
Thanks to everyone for reading all that stuff or just deleting it in the first place!!

admin · Post by **admin** » Sat May 24, 2003 2:11 am

Further to matters of pickup resistance, what is the resistance factor that is of greatest importance? Is the rating from the pickup itself, completely isolated from the instrument circuit, that is most important? While this is a pure measure of the pickup, might such a measure be somewhat artificial?

In the end, isn't it the resistance of the pickup as it is installed within the circuit that counts. In this case, doesn't the tonality stem from the overall resistance rating of the circuit and not just the pickup rating alone? Perhaps it is too early in the morning and I need to reflect more on this.

cooperman · Post by **cooperman** » Sat May 24, 2003 2:49 am

Accuracy of readings should be better than 5% when using Fluke electronic multimeter or similar quality instrument. The rest of the circuit should have little effect on the measurement on 5 control models as the only error will be due to each pickups volume pot being in parrallel with the reading. Very small error indeeed as long as the pot is full on of course.
As to how to measure, Thanks to 360dave for his instructions for four control two pickup models.

Why measure? I want to get some idea of which type of sounds characteristics go with particular values of coil resistance. Any way as 360dave says this is only for retentive sorts like us.(we are called trainspotter types in the uk)

admin · Post by **admin** » Sat May 24, 2003 2:56 am

Cooperman: It will be very interesting to see what comes out of this. Beyond the 2 X 2 contingency table that follows from the low versus high ratings X pickup type, it will be interesting to see what else develops.