[MRCA] VN-era speaker unit question
WA5CAB at cs.com
WA5CAB at cs.com
Wed Aug 21 23:18:28 EDT 2013
LS-7 and LS-11 were originally for use with SCR-284. They were carried
over for use with SCR-694-C and later with AN/GRC-9. LS-11 was also used with
AN/TXC-1. They may have been used with SCR-178 and SCR-179.
Both are WW-II vintage and have stamped steel cases and stamped steel front
covers. All originally had metal nameplates affixed.
LS-7-A, LS-11-A and LS-166/U are Korean War vintage and all have cast
aluminum cases and a cast aluminum front plate. The transformer is mounted to
the case instead of to the loudspeaker. Input impedances are 4000, 250 and
600 respectively. LS-166/U has a switch on the side with positions labeled
Vehicle and Pack.
The first four all have a cord terminated in either PL-55 (WW-II) or
PJ-055B (Korea). LS-166/U's cord is terminated in U-77/U.
The Vietnam vintage LS-454/U is the same as LS-166/U with two exceptions -
connector is U-229/U and no switch.
Another much rarer loud speaker is LS-590/U. A combination of LS-7-A and
LS-11-A, it has a cast aluminum case and cover, a PJ-055B and a tapped
transformer and selector switch to select either 250 or 4000 ohms input impedance.
It was used with AN/GRC-9(*), AN/VRC-34 and AN/TXC-1.
All of the cast aluminum case units have the nomenclature cast or engraved.
Robert D.
In a message dated 08/21/2013 14:30:46 PM Central Daylight Time,
jeepp at comcast.net writes:
> On 8/21/2013 8:23 AM, Rob Flory wrote:
> >Hi,
> >I am preparing a public demonstration of a TBX set where it would be
> >desirable to have audio that people standing around the set could hear.
> >
> >Do I have it right that the iconic VN-era speaker, which has a switch
> >on the side for "Field or Pack Set Use" or "Vehicle Set Use" has an
> >impedance through a transformer of hundreds of ohms in one of those
> >positions?
> >
> >I don't know the nomenclature for the speaker, as the example I have
> >doesn't have a tag. Can someone tell me the nomenclature?
> >
> >Unfortunately I don't have the TBX set to just hook it up and try it.
> >
> >Thanks, Rob
> >
> >
>
> Rob,
>
> The impedance of the LS-166 and LS-454 are both 600 ohms, of course.
> Both these speakers look the same and both have the nomenclature
> engraved on the side. I'm curious as to the one you might have? The
> LS-7 and LS-11 stamped metal speakers (with louvers) usually have
> painted-on nomenclature or a metal tag and are nom. 4000 ohms. They
> were, of course, for the GRC-9, et al. but do not have the selector
> switch. What connector is on the one you have?
>
> Jeep - K3HVG
Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
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