bases plates: brass vs. nickel

[ShannonH]

Ok, so i've been busy making pickups and rounding out my product offerings, when came across a weird conundrum. I have been working on a high output pick up with A8 mags, rolled it up to about 14k, and put a brass base plate. Now, the reason for the brass was my understanding that brass would milk some highs and increase the bass a bit. That really wasn't the case. The highs were more pronounced than they ought be in a wind like that. I have dropped an A2 magnet into the mix, and the tone is really PAFish, but still not bassy. I would not even say that the A2 tends toward being tubby in the bass end. I have wound pu's with A5 and nickel plate that have more bass than this.

Any one else have any experience with brass and it's relationship to tone? Thanks in advance.
Shannon

[StarryNight]

Have you tried an A5 with this pup? Any chance there's a short in the wire?

Ok, so i've been busy making pickups and rounding out my product offerings, when came across a weird conundrum. I have been working on a high output pick up with A8 mags, rolled it up to about 14k, and put a brass base plate. Now, the reason for the brass was my understanding that brass would milk some highs and increase the bass a bit. That really wasn't the case. The highs were more pronounced than they ought be in a wind like that. I have dropped an A2 magnet into the mix, and the tone is really PAFish, but still not bassy. I would not even say that the A2 tends toward being tubby in the bass end. I have wound pu's with A5 and nickel plate that have more bass than this.

Any one else have any experience with brass and it's relationship to tone? Thanks in advance.
Shannon

[ShannonH]

A5 is next. The pickup is fine as far as wiring goes. Everything is shielded, wrapped and beautiful. It doesn't sound bad, just not what i expected. If you've heard high output stuff like the Evolution by dimarzio, that is what it sounds like with A8. With A2 it sounds more like a duncan custom custom. Not bad sounds, just not what I expected, especially since I calculated the winds based on known quantities, like nickel baseplates vs. brass. The only other change was the magnet.

What tonal properties does brass add/change? I know we've discussed this before, but my experience doesn't jive with all the lore floating around out there.....

Thanks for the response!

[Possum]

...

Maybe there is a reason DiMarzio uses brass on most of its stuff, hmmmmm.....

[Artur pickupmaker]

This you call nickel baseplate is made of 100% nickel or is it an alloy?
I thought pure nickel was expansive and its magnetic behaviour would limit its use in pickup parts.

[David Schwab]

This you call nickel baseplate is made of 100% nickel or is it an alloy?
I thought pure nickel was expansive and its magnetic behaviour would limit its use in pickup parts.

They mean nickel silver, also known as german silver. The usual formulation is 60%-copper, 20%-nickel, 20%-zinc.

[Artur pickupmaker]

Thanks for the answer, David.

About the main question, is there a tonal difference between brass and german nickel silver covers? I think all my covers are brass and I'm sure it changes the tone, it fade the highs to get that smooth Tele neck single coil timber. Without the brass cover this pickup sounds almost equal to a Strat one.
German nickel silver does suffer magnetic attraction?

[ShannonH]

Thanks for the answer, David.

About the main question, is there a tonal difference between brass and german nickel silver covers?

Yes. Brass kills more highs. You may or may not like that. I don't. If you can get nickel covers, the highs will be smoothed out some but not completely eradicated. Maybe that's hyperbole, but I really hate brass covers.

Peace

[SK66]

I don't find baseplates have the same effects as covers do. Although brass is more conducive to eddy currents, as a baseplate it is exposed to much less of a fluctuating magnetic field thus the difference is much less notable.

Depending on the design, you may want to ground the magnetic poles to the baseplate (mechanical contact) and ground the baseplate if it's not already. If this is a HB bar mag type design, then the poles are probably already contacting the baseplate.

Of course, the stronger A8 is going to be brighter as it's aperture is narrower at a given distance from the strings. This pickup might optimally have to be further from the strings. A8 also has a fairly high permeance... Alnico 4 might be the best choice here... I suspect A5 will probably sound close to A8 in brightness (but not "character").

Also, the wind will have a huge influence. What gauge wire, how many turns, what shape coil, etc etc...

[LtKojak]

Ok, so i've been busy making pickups and rounding out my product offerings, when came across a weird conundrum. I have been working on a high output pick up with A8 mags, rolled it up to about 14k, and put a brass base plate. Now, the reason for the brass was my understanding that brass would milk some highs and increase the bass a bit. That really wasn't the case. The highs were more pronounced than they ought be in a wind like that. I have dropped an A2 magnet into the mix, and the tone is really PAFish, but still not bassy. I would not even say that the A2 tends toward being tubby in the bass end. I have wound pu's with A5 and nickel plate that have more bass than this.

Any one else have any experience with brass and it's relationship to tone? Thanks in advance.
Shannon

There are five AlNiCo8 grades, LNGT40, LNGT44, LNGT48A, LNGT48B and LNGT60.

Which one did you use?

[Possum]

....

Really the thing to do here is stop changing everything, test it as it is then substitute the nickel silver baseplate and listen to see what changes. I've never tried brass baseplates, so I don't know what they actually do. I'm sure DiMarzio uses them for a real reason and not because its cheaper....

[SJE]

There are five AlNiCo8 grades, LNGT40, LNGT44, LNGT48A, LNGT48B and LNGT60.

Which one did you use?

Well my fellow grade liker just a quick correction there the 8s are LNGT32, 34, 38, 40, 44 and a 8HC is LNGT36 and an isotropic 8 is LNGT18. LNGT60 is Alnico9.

[LtKojak]

Well my fellow grade liker just a quick correction there the 8s are LNGT32, 34, 38, 40, 44 and a 8HC is LNGT36 and an isotropic 8 is LNGT18. LNGT60 is Alnico9.

I've found those values in the Sensmag site. SHOOT ME!

[Mike Sulzer]

Measuring the differences between "nickel silver" and brass base plates

Current flows in the baseplate when current flows in the coil. The current in the baseplate affects the impedance of the coil. There are two different kinds of affects. There is a resistive effect because power is dissipated in the plate. There is an inductive effect because the voltage induced around a loop depends on the rate of change of the current in the coil. We want to make an impedance model to compare with measurements. This model consists of a complex impedance that goes in parallel with the coil. (Think of the load on a transformer.) The model consists of a resistor and an inductor in series: as the resistivity of the plate goes to infinity, no current flows.

The model implies that we should measure resistive effects at low frequencies and inductive effects at high frequencies, and a combination in between. The frequency of the transition depends on the resistivity of the plate, that is, the resistance in the model, and the inductance, which depends on the geometry (size and location of the plate, details of the coil), and the magnetic material in the coil.

The measurements are made with the I-V setup described in the discussion "A new model for…". A sequence of capacitors are placed in parallel with the coil, and the resonant frequency and the width of the resonance are measured, with and without the plates. The frequency is measured by finding the zero point of the phase. The width is measured by finding the lower and upper half power points.

Two plots are shown here: http://www.naic.edu/~sulzer/basePlatePlots.png. The lower one shows, for a given value of parallel capacitor, how much the resonant frequency changes when a baseplate is used. (The coil is one, that with slugs, from a Japanese-made PAF type pickup.) The horizontal scale is the resonant frequency with no plate, which is a function of the capacitor placed in parallel with the coil. The shift in frequency is due to inductive effects. As the frequency is increased, the inductance in the model dominates, and this inductor appears in parallel with the inductance of the coil. The resulting parallel inductance is lower than that of the coil alone. Thus the resonant frequency rises.

Notice that the frequency change with the nickel silver plate hardly changes up to five KHz. (This is approximately the useful frequency range of a guitar pickup when used with a normal cable and guitar speaker.) On the other hand, the frequency with the higher conductivity brass plate starts changing below 2 KHz.

The upper plot shows the Q of the resonant circuit. The Q is the frequency width of the resonance divided into the resonant frequency. The nickel silver plate lowers the Q significantly. The brass plate has a larger effect at low frequencies, but less effect at higher frequencies.

[Artur pickupmaker]

A thinner baseplate or cover would effect less the tone than the usual ones?