Inductive vs non-inductive resistors


Hey Wayne,

I noticed you reccomended non-inductive resistors for the crossover. The only ones I can get here are wirewound, and inductive type, I assume these could be used as well? Have done a search on this forum, and gotten a number of varying answers, but it seems to be that theres not much of a difference as the inductance is very small anyway, and close enough to a pure resistance.

I could get non-inductive resistors, but I would have to order them from an interstate location, and I would rather just buy everything from my electronics store, as I can get everything else there.

For the 40W resistors needed in the Pi Crossover, the document states use four 10W resistors in parallel: this would mean though very high resistor impedance values, series would be an easier way to get 40W, and smaller value per resistor. This is fine?

As for available inductors here.... the ones I can get state a 100W power handling at minimum and have an 0.8mm wire diameter, and an air core. For the Pi Crossover, one of the inductors is reccomended 10A rating.... current rating is not available on these inductors though. Would these work fine? (BTW: I would like approx 100W total system power handling for the xover..). (L)DCR is stated, and range from 0.25ohm to 1.4ohm depending on which value inductor you buy.

Capacitors cost so damn much in Australia... :-( Much more than at parts express.

Just getting onto C5, it says use Le/Re^2. For Alpha 6, this would be 0.19/7.2^2 = 0.0037uF.... this is a very very small value, I cant find this in the shops. Is this value actually correct?

Thanks!
Adrian


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