[R-390] Query re. 70v line xformer

Tue, 15 Jul 2003 22:07:20 -0400

Dave and all...
You use the 10 watt tap.  This by way of R=E^2/W.  Do the math and you'll
see that 10 watts yields an impedance of about 500 ohms.  Close enough....
I found several of these xformers in Greensboro for $2.49!!  Hooked one up
to my R-390A.  Hooked another xformer up to my ARC-5 rcvr and used the 3920
ohm tap (uuhhh, that is the 1.25 watt tap).  Both worked great.    What a
deal...
73's,
-tom

----- Original Message -----
From: Dave Kamp, KW0D <[email protected]>
To: <[email protected]>
Sent: Tuesday, July 15, 2003 9:52 PM
Subject: [R-390] Query re. 70v line xformer


> Hey All!
>
> Got one of these on-sale-specials from RadioShack... the 70v line
> transformer... got the 4-ohm secondary connected to an appropriate
speaker.
>  Which tap do I use for the primary?  They're not marked in impedance...
> they're marked at 0.62w, 1.25w, 2.5w, 5w, and 10w...
>
> For 600-ohms (er, 500ish) Do I use 0.62w?
>
> Cheers/73!
> DK  :-)
> ---------------------------------------------------------
> 73's from KW0D Dave in LeClaire, Iowa
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