Pickup Magnet Question

[JaySwear]

i had decided a long time ago that my telecaster would be a nashville style with 3 pickups. BUT i'm having some trouble picking out the 3rd pickup for it. the pickups i already have are ceramic. i'm looking at two different pickups, but one has alnico V magnets while the other has ceramic. i heard a long time ago that if you can it's a good idea to keep all magnets the same. is there any truth to that at all? i've tried to follow this rule when picking out pickups for other guitars i've built, but never thought to ask about whether there was any truth to this.

also, what differences could i expect between alnico V and ceramic magnets? thanks!

 

[line6man]

As long as the output impedance is the same, you can combine any pickups you want.
That is not to guarantee that they will sound good together, however, it would be in your best interest to just try it.

 

[Jusatele]

Ceramic magnets are usually stronger than Alnico, magnets, and not all alnicos are the same strength according to just the alloy number. It is kind of a crap shoot to buy according to the magnet type. So can be the trying to match according to impedance, The architecture of the windings can make this number hard to interpret, Your best bet is to buy matched sets or to buy pickups from matched sets. Thar can be hard also as just what Is the stock pups? A mis match is really frustrating having to adjust the volume every time you flip to a new setting. Guess what I am trying to say is take some time and research the pickup you want, sound files, and the impedance numbers, try to match magnet type, but also look at the size of the magnet, winding numbers are a big factor as is gauge of wire,and maybe a entire new set may be in the future.

 

[Cagey]

You don't have to keep the magnets the same. In fact, the primary reason to have multiple pickups is to get a wider variety of tonal qualities out of the same instrument, so different performance characteristics of the pickups are a Good Thing.

In my experience, ceramic magnet pickups are more brittle-sounding than Alnicos of any alloy. That may or may not be a Good Thing, depending on what you're listening for. It seems many people prefer Alnicos, but that may be the result of a concerted marketing effort to get mo' money out of players, since they cost a bit more to produce than ceramics do. There's more profit in a 50% markup of a $3 part than there is in a 50% markup of a $1 part.

 

[JaySwear]

the pickups i already know i'm using will be a Rio Grande Dirty Harry telecaster set. the pickups i'm debating between are the SM-1, SM-2, or SM-3 from Seymour Duncan. i'm pretty sure my choice would be the SM-2, but until i've got the funds i figure i should ask my dumb questions and research the crap out of my options. it looks like the SM-2 would match well with the Dirty Harry's according to the DC Resistance specs from warmoth's site.

 

[Cagey]

I don't know why anybody publishes DC resistance values for pickups, other than they're easy to get with a $10 multimeter. They mean almost nothing. It's like the recent fad of publishing the current draw specs on vacuum cleaners. Tells you nothing, other than how much current the motor draws, as if that has any bearing on how much vacuum the thing will pull. Could just be a cheap, inefficient motor or a demanding air pump.

DC resistance, if taken to an accurate enough degree, can tell you roughly how many winds there are on the thing, if you know the exact gauge of the wire. But, even that doesn't mean as much as it sounds like it does. The strength of the magnet, the permeability of the iron/steel in the core(s), the physical design, and other factors all contribute to a pickup's frequency response, range, output level and overall performance.

 

[Jusatele]

Cagey, if you have the same magnets, the same wire gauge, the same strength of magnetism, the winding bobbin is the same width and height, and a few other things , then the impedance number is valid, sort of. but all it gives you is the strength of the field.

 

[line6man]

I don't know why anybody publishes DC resistance values for pickups, other than they're easy to get with a $10 multimeter.

Yes, DC resistance is a meaningless measure. It does not tell you anything useful unless you are comparing identical pickups.

Thinner wire gauges have a higher resistance to direct current than thicker gauges, and of course, series humbuckers simply add the DC resistances of each coil together while parallel humbuckers decrease the value to 1/([1/R1]+[1/R2])

It pisses me off that a lot of people, and even pickup manufacturers and retailers sometimes think of DC resistance as a measure of output. DC resistance has no relation to output, except when you are comparing IDENTICAL pickups, in which case, the pickup with the higher resistance has more turns of wire, and thus, a higher output.

 

[lafromla1]

DC resistance has no relation to output, except when you are comparing IDENTICAL pickups, in which case, the pickup with the higher resistance has more turns of wire, and thus, a higher output.

Well isn't that right there a measure to use?

 

[dNA]

DC resistance has no relation to output, except when you are comparing IDENTICAL pickups, in which case, the pickup with the higher resistance has more turns of wire, and thus, a higher output.

Well isn't that right there a measure to use?

maybe, but not in this case because nobody here is comparing to identical pickups - we're talking about finding a DIFFERENT pickup to match the output of an existing set

 

[pabloman]

Cagey and his crazy conspiracy theories. You and Jesse Ventura crack me up.

 

[line6man]

DC resistance has no relation to output, except when you are comparing IDENTICAL pickups, in which case, the pickup with the higher resistance has more turns of wire, and thus, a higher output.

Well isn't that right there a measure to use?

Yes, but it only applies to identical pickups. The measure is useless for anything else.

You always see people posting the DC resistance of their pickups, but what does it matter?

 

[Alfang]

You guys that spout off about DC resistance reading meaning nothing, whats your point?

Heres My point, alot more people own a multi meter than own inductance meters and powersupplies. A lot more people understand resistance readings vs Inductance.

Most pickups are wound using 42 guage wire, far fewer are wound with 43 guage.  The type of magnet material doesn't influence the power or tone of the pickup. The only part of the magnet that counts is its magnetic power or Gauss.

The Bottom line is this, The resistance readings give you a ballpark idea to pre-evaluate what a pickup MIGHT soundlike.  If your a Grunge Metal player you wouldn't buy a pickup claiming 3Kohms resistance and so on.

It's just a guide and thats all,

 

[line6man]

And also, I forgot to mention that the DC resistance of a coil can change with temperature.

 

[Alfang]

well if the dc resistance changes due to temperature, which i know it does, then the inductance changes too, and therefore to a small degree the sound of the pup.

Resistance is the best means, other than actualy listenening to the pup, that we have.  Theres no other measure we can use.  I suppose listening to what others say works, but thats again someone hearing the pup work.

So anyone saying resistance reading are useless, come up with a better plan, and post it here

And by the way, any further argument about electronics and inductance and all that crap isn't gonna change my OPINION

 

[line6man]

well if the dc resistance changes due to temperature, which i know it does, then the inductance changes too, and therefore to a small degree the sound of the pup.

Resistance is the best means, other than actualy listenening to the pup, that we have.  Theres no other measure we can use.  I suppose listening to what others say works, but thats again someone hearing the pup work.

So anyone saying resistance reading are useless, come up with a better plan, and post it here

And by the way, any further argument about electronics and inductance and all that crap isn't gonna change my OPINION

Don't get me wrong. What I'm saying is people tend to totally misunderstand the concept of DC resistance and make way more of it than it really is.

 

[line6man]

Resistance is the best means, other than actualy listenening to the pup, that we have.  Theres no other measure we can use.

Millivolts...

 

[Jusatele]

Anyone here ever read that book about pickups, I think it is called "pickups windings and ....." Good book, explains why pickups are so complicated for such a simple idea, and why this discussion keeps going on. I will say this, after reading the book you have an entire new appreciation for matched sets of pickups

 

[Cagey]

Cagey, if you have the same magnets, the same wire gauge, the same strength of magnetism, the winding bobbin is the same width and height, and a few other things , then the impedance number is valid, sort of. but all it gives you is the strength of the field.

DC resistance of a coil is not a measurement of impedance. Impedance is frequency-related. And the number of winds can be anywhere from 1 to 78 bajillion, and it won't change the "strength" of the field on a pickup. Only the magnet and the permeability/size/orientation of the cores can change that.

 

[line6man]

DC resistance of a coil is not a measurement of impedance.

Exactly. DC resistance is only the real measure of resistance to a direct current. Impedance is made up of both a real resistance and an imaginary reactance.
If the reactance is 0 ohms, you have a resistive impedance. If the reactance is above zero ohms, inductive or capacitive, you have a reactive impedance, (As is the case with pickups. ) which is frequency dependant, as the reactance varies with frequency.
Inductive reactance (Which is the angular frequency times the inductance.) is proportional to frequency, and capacitive reactance (Which is the inverse of the angular frequency times the capacitance.) is inversely proportional to frequency.