[R-390] Speaker 600

[Dave Maples]

All: Cecil's recommendations are all sound.

I have used a standard 70.7 V transformer rated at 10 watts for this.  It
comes out to 500 ohms, which is plenty close enough for this purpose.  If
you can locate an 8-watt 70.7 volt line transformer, that comes out to 625
watts.  I don't think you'll do much better than that.  both the 10-watt and
the 8-watt 70-volt transformers are pretty easily located.  Another
possibility is a 25-volt, 1-watt transformer.  That also comes out to about
635 ohms (again plenty close).

For what it's worth.

Dave Maples

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]On Behalf Of Cecil Acuff
Sent: Wednesday, September 22, 2004 8:47 PM
To: Charles B; R-390 at mailman.qth.net
Subject: Re: [R-390] Speaker 600


Greetings Chuck,

        Well there are a couple of routes.  You can watch the auction site
and find one on there....they are usually fairly easy to find...but you
never know for sure what kind of shape the cone and voice coil are in.

What most folks do is use a high quality 8 ohm to 600 ohm transformer to do
the conversion to a more conventional speaker.  Many of the guys are using a
specific Radio Shack speaker and transformer combination.  I have also heard
you can use a 70 volt line transformer to do the conversion.

One other option is to connect a nice stereo amplifier and speakers to the
diode load terminal on the rear of the R-390X through a coupling capacitor.
If you search the archives you will find a good bit of discussion in years
past on all the above.

Good luck!

Cecil Acuff
----- Original Message -----
From: "Charles B" <ka4prf at us-it.net>
To: <R-390 at mailman.qth.net>
Sent: Wednesday, September 22, 2004 3:39 PM
Subject: [R-390] Speaker 600


> Hi all,
>
> Where can I find a 600 ohm speaker or where can purchase one?
>
> Is it possible to convert an 8 ohm speaker to 600 ohms?
>
> Thanks
>
> Chuck
>
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