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Update on 38-5 restoration, Almost ready for cabinet!
#10

(10-29-2016, 08:35 PM)TerryMSU Wrote:  Ron, my personal inclination would have been to stick with a field coil design as you suggested for the exact reasons you suggest.  Terry, the magnetic field is proportional to the product of turn count and .  Double the turn count and you can use half the current.  In any case, I am very appreciative of the input all three of you folks have provided.  While I have the engineering knowledge and experience to know what might be possible, I am lacking in the practical wisdom that you all have provided.  If the cabinet I am considering pans out and my current chassis is functional, I will definitely be looking for more advice.  The idea of other Philco speakers in a similar size had not crossed my mind.

The cabinet (if I take it) will be coming from Alabama to Michigan.  Any recommendations on how to ship it safely and cheaply?

Thanks so much,
TerryMSU

> Double the turn count and you can use half the current.

This is true but you end up with a coil that is physically larger in less you shrink the size of the wire.
In terms of using and resistor I was thinking of cost also  (it's cheap like me). A choke (or field coil) is much more efficient in reducing ac hum in comparison to a resistor. If the resistor was the same size FC I would think that the heat generated would be about to same as weather you are use either, both are dissipating the same amount of energy.
You can use a separate choke mounted on the basket of a pm spkr, mounted like the opt. Something like 5H @ 70ma should do the trick. You could go higher in inductance but size maybe an issue.
If you want to have a set that looks original by all means go with a Philco spkr but I'm thinking it may be a bit harder to find and may need reconing.

Just wanted to throw out the most options.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry


Messages In This Thread
RE: Question on philco 38-5 restoration - by Radioroslyn - 10-29-2016, 10:43 PM



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