[TechAssist] Re: Sears antique radio, transformer problem

Not ohm meter ohms - impedance ohms! Impedance ohms are not easy to measure.
Easiest way is to look it up in the transformer manufacturers catalog. Also
the transformer has to have enough iron to handle the DC current without
saturating. It needs big wire to have low ohm meter ohms in order to be
efficient and send the power to the speaker instead of burning it up in the
transformer.
Jerry Silverman Greentron Inc
Mail to: greentron@xxxxxxx
4 Newland Ave Greenville SC
29609                864 232 3889
----- Original Message -----
From: "KENNETH BARNES" <KENNYB928@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, January 09, 2006 5:22 PM
Subject: [TechAssist] Re: Sears antique radio, transformer problem


>   Russ:  Thanks for your reply.  I hooked another transformer in circuit -
primary reads 175 ohms, secondary .7 ohms.  Speaker doesn't give good sound
as you said.  Bad transf. is about 3 times larger than the one I subbed for
and iron core is much larger in the bad transf.     Any ideas?    Thanks
again.   Kenny
>   ----- Original Message -----
>   From: Hoyt's TV<mailto:hoytstv@xxxxxxxxxxx>
>   To: techassist@xxxxxxxxxxxxx<mailto:techassist@xxxxxxxxxxxxx>
>   Sent: Tuesday, January 03, 2006 2:12 PM
>   Subject: [TechAssist] Re: Sears antique radio, transformer problem
>
>   You can figure it out by the type of output tube they both fit. Look
them up
>   in an RCA tube manual. I believe will tell you the output impedance for
the
>   tubes. Tubes weren't too fussy though, I think you could get by with
most
>   any output transformer for a radio of similar type. Likewise the tube
won't
>   care too much about using a 4 ohm speaker with an 8 ohm transformer.
However
>   your audiophile customer may go ballistic when those 25kc notes that
he's
>   accustomed to hearing crystal clear, become a little distorted.
>
>
>   Russ Hoyt
>   Hoyt's TV
>   Exeter, NH
>
>
>   ----- Original Message -----
>   From: "KENNETH BARNES" <KENNYB928@xxxxxxx<mailto:KENNYB928@xxxxxxx>>
>   To: "techassist"
<techassist@xxxxxxxxxxxxx<mailto:techassist@xxxxxxxxxxxxx>>
>   Sent: Tuesday, January 03, 2006 12:07 PM
>   Subject: [TechAssist] Re: Sears antique radio, transformer problem
>
>
>   > Sears antique radio - Question:  A transformer mounted on the speaker
is
>   > open on the primary.  The secondary winding on the transformer is .5
ohms.
>   > The B+ feeding the transformer primary is 90 volts.  The speaker is
3.6
>   > ohms.  I have a good transf. from another speaker which is 8 ohms, the
>   > secondary winding is .7 ohms, the primary winding is 175 ohms.  Can I
use
>   > this transformer in place of the bad one?     TIA            Kenny
>   > Kenny Barnes TV
>   > 928 S. Marshall St.
>   > Boone IA 50036
>   > 515 432 5250
>   >
KENNYB928@xxxxxxx<mailto:KENNYB928@xxxxxxx<mailto:KENNYB928@xxxxxxx<mailto:K
ENNYB928@xxxxxxx>>
>   >
>


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