[MRCA] Loudspeaker, Crystal LS-685/U

[B Smith]

 SJ 18/2 "cord" ( type black, stranded wire size 18, two conductor,) 
available from your local electrical supply house makes an excellent 
speaker cord and has a rubber insulation.  SJ cord with larger wire 
sizes make excellent power cords. The white "cord stamped labels  with 
wire size etc is easily removed.
I usually put a 1 inch section of yellow heat shrink 3 inches from the 
end to make it look official.
Z

--------------------------------------------------
From: "Al Klase" <ark at ar88.net>
Sent: Thursday, May 10, 2012 2:57 PM
To: "Military Radio Collectors Association" <mrca at mailman.qth.net>
Subject: [MRCA] Loudspeaker, Crystal LS-685/U

Gang,

Most back-pack radios were not designed for loudspeaker operation, but
there are a lot of situations where a speaker is a handy addition.
Something like an LS-166 will plug right in, but there generally isn't
enough audio do make it as loud as you'd like.  Plus, the damn thing
weighs 3 1/2 pounds.  (Just the thing for hand-to-hand combat.)

Alex, K2AJR showed up with an LS-685 at the recent MTA meet in 
northern
NJ.  He later emailed regarding an E-bay seller who had the 
two-for-$20,
shipped.  I ordered a pair immediately.  They arrive the other day.

This speaker was designed to be used with some component of the 
Singars
family.  It's plastic and weighs 1 pound.  The connector is wired
strangely, and was designed to NOT mate with the standard U-228 we all
know and love.

Disassemble the connector, and move the wire on PIN-E to PIN-B.  While
the connector is apart, grind away the extra locking lug adjacent to
PIN-E.  This make it a U-229 equivalent.  The cord on the first 
speaker
I worked on was defective.,  There had to be some reason the Army 
threw
it away.

Connected to a PRC-77, the LS-685's acoustic output measured within a 
dB
or so of my LS-166.  However, when connected to my PRC-104 the LS-685
was 10dB louder, a welcome improvement.  A quick measurement of the
speakers impedance showed 200-300 ohms, versus 600 for the 166.  So if
the radio has a lower output Z, this speaker will be louder.

6 ounces of the weight of the stock speaker is the heavy shielded coil
cord.  I went with a lighter cord and cut the total weight to 11 
ounces.

The speaker has a built-in belt clip on the back, which in turn has a
key-hole punch out that can be hooked over a handy screw.  I think I
like it!

Al

-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

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