[Milsurplus] LS-3 question

[Robert Downs]

Eugene,

 

There is no smaller diameter 2-circuit plug of the same diameter as the
WW-II or earlier PL-68 or the Korean War or later PJ-068B.  The LS-3 that
you have has the correct 3-circuit jack on it.  If your BC-312 has a
2-circuit 1/4" jack at the Speaker 2nd Audio position, then some numb-nuts
swapped it.  And I hope that he at least had enough sense to either remove
the wire going from the original jack back to +12VDC or at least to insulate
the bare end of it.  The Phones 1st Audio jack, on the other hand, has the
1/4" dia. 2-circuit jack to operate a Headset.  But it wouldn't run the LS-3
anyway.

 

The reason behind all of this is two-fold.  Second, if someone is monitoring
a circuit with Hi-Z headsets and someone else jacks in an LS-3, the
headset(s) go dead or at least much quieter.  But first, the BC-312 was the
first of the four similar sets developed.  When development began, the
standard loudspeaker that it was to use was an electro-dynamic or field-coil
type.  Then someone else invented Alnico and the LS-3 and other speakers
quickly became the standard.  It wasn't until near the end of BC-312/314
production that the 12VDC wire was eliminated.  The BC-342/344, however,
never had the third wire installed as in most cases, 12VDC was not
available.  But they did have the JK-33 for Speaker-2nd Audio.  Just like
the BC-312/314.  And did use a 3-wire cable to connect the LS-3.

 

Robert Downs

 

From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of W2HX
Sent: Thursday, November 11, 2021 09:54
To: milsurplus at mailman
Subject: [Milsurplus] LS-3 question

 

Hi all,

 

I have an LS-3 that I plan to connect to my BC-312. The 312 loudspeaker jack
fits a PJ-055B (1/4"), however the LS-3 has a smaller diameter jack. A
PJ-068 fits fine into the LS-3, however the PJ-068 is a 3 pole connector and
I only need a two pole. What is the right designation for a plug with the
same diameter as the smaller PJ-068 but with only two poles? Or was the LS-3
expected to just use two of the three poles of a PL-068?

 

73 Eugene W2HX

Subscribe to my Youtube Channel:
https://www.youtube.com/c/w2hx-channel/videos

 

 

 

 

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