[R-390] Speaker

[Jerry K]

At least on board ships, almost never was a speaker driven directly from a
receiver output. All receiver audio was taken from line outputs and wired to
a batch of audio "patch" panels (actually just a bunch of multipole switches
in a x-y matrix). Wired to the same patch panels were "Speaker-Amps" (don't
remember the designation of the amps) strategically placed around the ship,
which in turn were hardwired to an accompanying speaker, usually an LS-166
type. In Radio Central you could simply walk over to the patch panel and
connect any receiver to any speaker-amp (or to any CW operating position's
phone jack) by a simple twist of the correct switch. Similarly, you could
switch any transmitter and it's audio/key/sidetone lines to any place on the
ship you desired, as long as that place was wired with a mic and speaker/amp
or phone jack/CW key position. Fidelity wasn't the issue, communications
readability was, and readability was pretty good when teamed up with the
proper amp. For obvious reasons most CW operation was done from dedicated CW
positions in the radio shack, where a mill, hand key, set of phones, and a
stack of R-390A's (or whatever) was available directly in front of the
operator.

It has always surprised me that those audio switching panels (usually
comprised of a 5x10 matrix of multipole rotary switches) aren't seen on the
surplus market and used by hams. I'd love to have two or three myself. They
were compact, extremely reliable, and simple to wire up and use. Heck, they
were so reliable maybe they are still using the same ones and none have ever
been surplused!

Jerry W5KP


-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]On Behalf Of Paul H. Anderson
Sent: Thursday, September 23, 2004 8:20 AM
To: Bruce Stewart
Cc: r-390 at mailman.qth.net
Subject: Re: [R-390] Speaker



I found that the LS-166 sounds pretty awful (at least mine do).  I
modified a used LS-166 by removing the vehicle/something rotary switch,
putting a switching quarter inch plug in its place.  I wired it so that I
could plug in external 8 ohm speakers (which shuts off the internal
speaker), or remove the plug and use the LS-166 as-is.  Seemed to work
pretty well.

But I prefer the diode load approach most, since I just ran the output
over to a cheap powered speaker from a computer.  A long time ago, someone
posted a simple DC isolation circuit for it that I made.  I don't remember
the values of the resistor and capacitor.

Paul

On Wed, 22 Sep 2004, Bruce Stewart wrote:

> Hi All,
> I have always used a LS-166/U speaker with my R-390's.  You would just
need
> to change the cable or U-77 connector.
> Bruce
>
>
> ----- Original Message -----
> From: "mikea" <mikea at mikea.ath.cx>
> To: "Charles B" <ka4prf at us-it.net>
> Cc: <r-390 at mailman.qth.net>
> Sent: Wednesday, September 22, 2004 4:54 PM
> Subject: Re: [R-390] Speaker
>
>
> > On Wed, Sep 22, 2004 at 08:53:38PM +0100, Charles B wrote:
> > > Hi all,
> > >
> > > where can I find a 600 ohm speaker?
> >
> > They're not very common, but 600-to-8 ohm transformers are; I use
> > 'em on all my military radios with 600-ohm speaker outputs.
> >
> > --
> > Mike Andrews

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