Optimizing the Big Dummies

[fieldwrangler]

Folks -

Seems to me that equal turns/area product low resistance/inductance dummy coils are worth optimizing.

It also seems that the spectrum of noise produced by the hi-z sense coil will differ significantly from that of the Big Dummy.

True?

Addressable?

Bob Palmieri

[Mike Sulzer]

Folks -

Seems to me that equal turns/area product low resistance/inductance dummy coils are worth optimizing.

It also seems that the spectrum of noise produced by the hi-z sense coil will differ significantly from that of the Big Dummy.

True?

Addressable?

Bob Palmieri

With the coils connected in series the two inductors kind of act as a single one. At very high frequencies, the capacitance of the pickup coil has an effect, and the cancelation will not be as good.

[fieldwrangler]

With the coils connected in series the two inductors kind of act as a single one. At very high frequencies, the capacitance of the pickup coil has an effect, and the cancelation will not be as good.

Ah! Do you mean that they combine to form a filter that then affects both of their noise signals?

Also, the high end is indeed where I'm still hearing some noise...

[Mike Sulzer]

Ah! Do you mean that they combine to form a filter that then affects both of their noise signals?

Also, the high end is indeed where I'm still hearing some noise...

Yes.

Edit: And you might be able to get rid of some of that high frequency noise by adding a capacitor across the dummy. It would have a larger value than the pickup coil capacitance.

[jvin248]

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A thread on large dummy coil designs that may help is over here.

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[fieldwrangler]

Yes.

Edit: And you might be able to get rid of some of that high frequency noise by adding a capacitor across the dummy. It would have a larger value than the pickup coil capacitance.

In fact, this is exactly my focus for today!