C5s

[big_teee]

Does anyone know what the gauss readings are for C5 Bar Magnets.
I suppose they would be similar to A5 Bar magnet readings?
I show that A5s are around the 680 range, and C8 in the 1400 range.
If C5 was in the 650-800 range that could be very useful!
It looks like there would be more applications for the C5s than the C8s.
T

[marku52]

here is some stuff to watch out for: AFAIK, the conductivity of C material is very low compared to A, so A has some eddy current losses that C won't have. This may be why C mag'd pups are often described as "bright" or harsh.

This was brought home to me when I had a coil that I could insert a bar magnet into. There was a noticeable drop in Q, and increase in L when I put the A bar magnet into the coil. And the results were different for A2,3 and 5 because their alloys are all different.

I don't know what the magnetic permeability of C is, for A it is slightly greater than 1, so that the L of the coil goes up when you put the magnet into the circuit. You might not get that with C, but an Extech meter shows the effect readily with A.

Since C won't have the eddy losses that an Alnico magnet pup has, you might benefit from putting the pup in a brass can (the extech also shows the Q of the coil dropping significantly when I set the coil on a sheet of brass)

[big_teee]

So say if the Ceramic magnet bottom is a thin metal baseplate, like the De Armond.
I Would think there would be some eddy current effect then.
I would think the bright and harshness would more pronounced with the C8 compared to C5.
I did some sound testing with a humbucker, with a A8, & C8 Magnets at different gauss strengths.
The A8 Was stronger than the C8 at full strength, but the C8 always sounded brighter.
I would still like to know the Gauss readings of the C5 if anyone has any info on that.
Thanks,
Terry

[marku52]

"the C8 always sounded brighter." My guess would be that is the helpful effect of the eddy current losses in the Alnico. The Extech meter (recommended on this forum) makes measuring effects like these so easy, it is a wonderful tool. Tho I do doubt its capacitance numbers. Instead I get those from a pulse resonance measurement with a scope.

unfortunately, I don't have any numbers on gauss for a C5 bar.

[Joe Gwinn]

The Extech meter (recommended on this forum) makes measuring effects like these so easy, it is a wonderful tool. Tho I do doubt its capacitance numbers. Instead I get those from a pulse resonance measurement with a scope.

You are right to doubt the Extech capacitance numbers while measuring a pickup, and the resonance method is correct.


The Extech measures the complex impedance of whatever it is connected to, and computes parameter values according to which model circuit is implied by the user's choice of L, C, or R, and SER or PAR.

[big_teee]

Where do you buy these extech meters, and what all can you do with them?
And what model of the extech is the most bang for the buck?
Terry

[kevinT]

did some measurements a while back. see thread.


http://music-electronics-forum.com/t4515/

[rdrr]

I have some C5 3.25 x .375 X .25 bar magnets. All of them register around 1000 with my ghetto gauss metter made with a hall effect sensor and a digital multi meter.

[big_teee]

did some measurements a while back. see thread.


http://music-electronics-forum.com/t4515/

Kevin:
Very interesting gauss results.
I was expecting a very large difference in C5, & C8 Gauss readings.
They were nearly identical.
So my next generic question, without getting into anyones trade secrets is.
What would be the difference in sound generally. I know C8 is used the most.
I have access to buying both, and was really looking for a little weaker version of ceramic.
So anything you can add on tone differences would be greatly appreciated!
Thanks,
Terry

[marku52]

there was a thread on this a while ago, it was by the recommendation of the forum that I bought this one. Not just any LCR meter is able to accurately measure a very lossy inductance (which is what pups are). the Extech does this very well. the model number is 380193, I don't know if other Extechs do as well. I found the best price on Amazon for it, about $210.

Amazon.com: Extech 380193 Passive Component LCR Meter: Home Improvement

[marku52]

Yes, but this is what it does when it measures L and Q as well. It does that fine, it is just the C measurement that doesn't correlate with other ways of measuring (like coil resonance method). My guess is that for the L portion, modeling as a series R + L works pretty well, while for a *distributed* capacitance, neither series nor parallel works very well.

I tried modeling pickups in spice for a while, even modeling the coil as a multi-element array of 10 L-C-R elements (to simulate the distributed nature of it) or so wouldn't correspond to what I'd see with an o'scope.

[big_teee]

I have some C5 3.25 x .375 X .25 bar magnets. All of them register around 1000 with my ghetto gauss metter made with a hall effect sensor and a digital multi meter.

Very good rdrr.
Would you care to tell us more about your Ghetto gauss meter.
I would like to do the same. I have a high quality Fluke 89 meter.
I presume your sensor converts to mv. You take the mv and call it gauss?
Please share!
Thanks in advance,
Terry

[Mike Sulzer]

Yes, but this is what it does when it measures L and Q as well. It does that fine, it is just the C measurement that doesn't correlate with other ways of measuring (like coil resonance method). My guess is that for the L portion, modeling as a series R + L works pretty well, while for a *distributed* capacitance, neither series nor parallel works very well.

I tried modeling pickups in spice for a while, even modeling the coil as a multi-element array of 10 L-C-R elements (to simulate the distributed nature of it) or so wouldn't correspond to what I'd see with an o'scope.

I think the reason the Extech does not measure the C is the low Q (about 10 K of resistance across the C), not the distributed nature of the C.

Note on the Extech: As Joe said, it supports a series and parallel model. A humbucker has both series resistance and parallel loss due to eddy currents. Neither model applies, and you can expect errors in both the L and effective R.

[big_teee]

Anyone ever compare tonally the difference between C5 & C8 Magnets?
Terry

[rdrr]

Very good rdrr.
Would you care to tell us more about your Ghetto gauss meter.
I would like to do the same. I have a high quality Fluke 89 meter.
I presume your sensor converts to mv. You take the mv and call it gauss?
Please share!
Thanks in advance,
Terry

Yep, thats about it. I followed this instructions on this page Build your own Gaussmeter
Was pretty simple and cost less than 3 bucks, including shipping. I'm just starting out winding and didn't want to spend to much. I'll eventually move on to something a bit more robust after I get the hang of things but this works for me for now.

Rob