How Much Variance in DC Resistance readings is Acceptable?

[MetalManiac]

Hi

I just received a set of older early 2000's well used custom wound pickups. They have a little rust on the magnets.

Well the published winders specs are Bridge- 7.25K, Midddle-6.35K, and neck-6.30K

The seller had the DC readings listed as bridge 7.5K, Middle and neck 6.5K ( EDIT- Neck pickup is 6.05k, NOT 6.5k)

I just now took the dc resistance readings and they are as follows- Bridge- 6.90, Middel 5.92, and neck 6.5K.

They do appear to have been monkeyed wih compared to a different set I have from the same winder.

Thoughts?

 

[JB_From_Hell]

Re: How Much Variance in DC Resistance readings is Acceptable?

Temperature can affect that, but I don't know how much.

 

[MetalManiac]

Re: How Much Variance in DC Resistance readings is Acceptable?

^ yes, there are variables. Not certain exactly what , so hopefully can get some definitive info.

The other set I have does read higher resistance than published. These are likely expected to be different form the tight tolerance 100% CNC major manufacturers stuff.

 

[idsnowdog]

Re: How Much Variance in DC Resistance readings is Acceptable?

^ yes, there are variables. Not certain exactly what , so hopefully can get some definitive info.

The other set I have does read higher resistance than published. These are likely expected to be different form the tight tolerance 100% CNC major manufacturers stuff.

I did an experiment a few years ago with the same pickup at body temperature and outside at 0 degrees for one hour and there was a 2K difference between low and high. So what you're seeing isn't that strange given normal room temperatures.

 

[jeremy]

Re: How Much Variance in DC Resistance readings is Acceptable?

the fact that some are off significantly more than others is odd though. if the neck and middle are both supposed to be 6.5k and one is 5.9 and the other is 6.5 seems weird. not bad at all since the set might sound great but kinda weird

 

[blueman335]

Re: How Much Variance in DC Resistance readings is Acceptable?

Temperature can affect that, but I don't know how much.

What temps are PU readings tested at? Warmer or colder than that will give different results.

 

[Myaccount876]

Re: How Much Variance in DC Resistance readings is Acceptable?

Your neck is +7.4% off, middle is -8.9% off, and your bridge is -8.0% off. I can't remember if SD's tolerance is 5% or 10% (to give insight on what is the standard), but this isn't SD and those numbers are approaching 10% off. You can decide if that is too much for you.

 

[LtKojak]

Re: How Much Variance in DC Resistance readings is Acceptable?

The only definitive info you can gather is the following:

DC readings, without any other context indication, are meaningless.

HTH,

 

[regan]

Re: How Much Variance in DC Resistance readings is Acceptable?

How good is your multi-meter?

How old is it? if it's old has it ever been recalibrated?

What condition are the probes/croc clips in?

 

[crusty philtrum]

Re: How Much Variance in DC Resistance readings is Acceptable?

Are you checking your meter readings by first connecting the probes directly together to see if you get a reading of zero Ohms ? Cheap or ageing probe cables can add some resistance of their own, and not always consistently.

Try running your measurements on different days and/ or in different locations. Write down the results.

Then 'calibrate' the set. I.e. the one that is most consistently the highest reading will be the one to use for the bridge, and you'd probably use the lowest-reading one for the neck.

After that, install into guitar, set up, play and enjoy. After all, you have no idea of how the magnets may have been affected during their life, and you can't measure that, so there's no point being too pedantic about it, and DC resistance measurements are known to be only a rough guide.

Or is that too sensible ?

 

[GuitarDoc]

Re: How Much Variance in DC Resistance readings is Acceptable?

Your neck is +7.4% off, middle is -8.9% off, and your bridge is -8.0% off. I can't remember if SD's tolerance is 5% or 10% (to give insight on what is the standard), but this isn't SD and those numbers are approaching 10% off. You can decide if that is too much for you.

Those are variations from what the seller published. But the differences are smaller compared to the mfr specs:
bridge = -4.8%, middle = -6.8%, neck = +3%.

But what if you (or the seller) got the middle and neck readings mixed up?! Then you would have a variance from mfr specs as follows:
bridge = -4.8%, middle = +2.4%, neck = -6%

But from the seller's readings as follows:
bridge = 8%, middle = 0.0%, neck = -2.2%

I think that actual readings should at least be within 5% of the mfr listed resistances (10% would be too sloppy/inconsistent, as far as I'm concerned). Your actual readings are pretty close to that 5% tolerance level and temperature could certainly be accounting for much of that difference.

 

[Myaccount876]

Re: How Much Variance in DC Resistance readings is Acceptable?

Ah, I didn't check mfr specs - I just assumed the "right" (wrong) specs given by the seller in the OP were right.