[R-390] 600 to 8 ohm speaker converter

[Thomas Chirhart]

We used the LS-474 with the R-300’s, R-1051’s etc onboard ship in the Navy. I have a bunch of them getting packed up for a hamfest next month along with other R-390 parts. Not sure if posting FS listing is authorized here or not. 73
Tom K4NCG- VA

Sent from my iPhone

> On Feb 14, 2022, at 2:26 PM, Steve Toth via R-390 <r-390 at mailman.qth.net> wrote:
> 
> AND IIRC there is the junk box solution: if you really need a quick working low-buck fix and can't find the correct parts, you can use a 115v to 12.6v filament transformer to connect the 600ohm output impedance to the 8ohm speaker.
> - Steve  W7SJT
> "Always look for a positive solution then Improvise, Adapt, and Overcome"
> 
> - adaptation of the U.S. Marine Corps motto
> 
> "Every day is an opportunity to challenge the achievement of your dreams"
> 
> 
> "Success is not final, failure is not fatal.  It is the courage to continue that counts."
> 
> 
> - Winston Churchill
> 
> 
> 
> 
> On Monday, February 14, 2022, 12:17:07 PM MST, Barry <n4buq at knology.net> wrote:
> 
> If I remember correctly, a 70 volt line speaker transformer can be used and I think that's what you're showing on the left.  An 8-ohm speaker goes to the 8-ohm output lines and the line output goes to one of the wattage taps.  I can't see the labeling on the back side of the transformer in you picture so not sure which wires those are but typically there would be one common input with multiple taps for various wattage (or volts).  As I recall, there is a recommended tap to use but I think I tried a few of them to see which one gave the best output.
> 
> HTH,
> 
> Thanks,
> Barry - N4BUQ
> 
> ----- Original Message -----
>> From: "K PERALES" <kenperales at comcast.net>
>> To: "R-390 Mailing List" <R-390 at mailman.qth.net>
>> Sent: Monday, February 14, 2022 12:49:17 PM
>> Subject: [R-390] 600 to 8 ohm speaker converter
> 
>> When I got my R-390 it has what I assume to be some kind of transformers to
>> allow a modern 8ohm speaker to be hooked up.  I did not think to diagram how
>> the wires were hooked up.  Is there any manual that tells a non-electrician how
>> to connect these transformers to the R-390A to let me listen without
>> headphones.
>> 
>> Ken
>> 
>> 
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