Three Questions

[Jim Simmons]

Alan,

To answer #2, without access to an impedance meter, the simplest way is to
measure the DC resistance of the voice coil.  If it's less than 4 Ohms but
greater than 2 Ohms, then it's a 4 Ohm speaker.  It it's less than 8 Ohms
but greater than 4 Ohms, then it's an 8 Ohm speaker. If it's less than 16
Ohms but greater than 8 Ohms, then it's a 16 Ohm Speaker.  The reason for
this is because impedance is a combination of both AC and DC resistance.
More specifically, Z= square root of (XL squared + R squared)...The
Pythagorean theory.  For the nominal speaker impedance to be equal to, say 8
Ohms, then the DC resistance must be less than 8 Ohms.  The XL value will
depend upon frequency, but if I remember correctly the impedance of speakers
was determined by impedance measurement at either 400Hz or 1000Hz.  Either
one of these will be close to ballpark and therefore "nominal".

Wow, my students always told me if they asked me for the time I would tell
them how to build a clock.  .... ..   Hope this helps.

Jim
N5MSJ

-----Original Message-----
From: Boat Anchor Owners and Collectors List
[mailto:BOATANCHORS at LISTSERV.TEMPE.GOV] On Behalf Of Alan W. Fremmer
Sent: Friday, February 10, 2006 11:42 AM
To: BOATANCHORS at LISTSERV.TEMPE.GOV
Subject: Three Questions

Fellow Collectors/Restorers,
 
I'm confident that you guys and gals out there will have the answers  and so

allow me to thank you all in advance.
 
#!1.  Until I can find a Globe modulator for my Globe Chief Deluxe,  would 
like to use an EICO 730.  The Globe manual shows pin outs for the  accessory

socket but doesn't mention what the impedance match should be.   The Globe
Chief 
has two 807's in the final.
 
#2.  On the subject of impendence, is there as easy way to determine  if a 
loud speaker is 4, 8 ,16, etc. ohms.  There is no label on the one I'm  
concerned about
 
#3  In the October 2005 "Electric Radio" magazine, there's an article  about

modifications to the DX-60 which includes protecting the function  switch.  
The author uses insulated posts screwed onto the power transformer  as tie 
points.  Any idea where I might find those? 
 
Thanks again for your suggestions.
 
73, Alan - KB2HEI

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