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Vintage threads from the first ten years

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7/3/2004 5:49 PM
Sheldon Dingwall
How useful is testing inductance?  
Is testing output via a driver coil, frequency sweep and plotting a graph more useful?
7/4/2004 12:01 AM
IMO inductance is a significant factor, probably the "most significant" in the "tone" of a pickup and it's "character" ("character" as determined by the coil only)
7/4/2004 8:19 PM
Sheldon Dingwall

What frequency do you measure at?  
Are the little Fluke style digital meters any good?
7/4/2004 11:55 PM
Dave Stephens
I've found that inductance is fairly reliable, but once you get into humbuckers it doesn't mean the same reading as you get on single coils, and this has thrown me for a loop trying to figure out what humbuckers are actually doing tone wise with winds and wire. 5 henries on a bucker and 5 henries on a strat coil sound very different to me.  
Wavetek Meterman has a good meter that measures inductance for about $100, plus it has a nice blue backlight in the readout. Search around on the web for the best price......Dave
7/6/2004 12:44 AM
Lately, I've been experimenting with measuring inductance, not just for pickups but for output transformers and such. I've been doing it by putting a resistor in series with the pickup, applying a test frequency, then using the ratio of applied voltage to resistor voltage to calculate the inductance. I'm using a test frequency of 1000Hz and the method is giving me good results. The test frequency shouldn't be any higher than 1000Hz because the stray capacitance of the pickup starts to become important and it will throw off the calculated inductance value. By the way, a similar method can be used to measure the pickup's resonant frequency and then use the frequency to calculate Q and the pickup's stray capacitance.  
I can give the equations needed to make the calculations, but only if someone's interested. Years ago, I used to post equations here on Ampage but I found that nobody found them particularly useful.
7/6/2004 1:57 AM
Fred Hammon

Sounds interesting but perhaps tedious to some of us "Ludites". If you could present the equations in such a way that a mathmaticaly challenged pickup maker could plug it in, I'd like to give it a go.  
I suppose now is the time to learn.  
How is this different from Dave's inductance meter?
7/7/2004 2:38 AM
Dave Stephens
I'd be interested in the formula.....Dave

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