WWII US SIGNAL CORPS LOUD SPEAKER LS3

Speaker used with military communication equipment. Currently plugged into a HRO receiver in the Museum. However the HRO receivers we have require a 7000 ohm impedance unit.

Your comments:

• The LS-3 loudspeaker is a permanent-magnet type speaker, housed in a steel case, made by various manufacturers.
  It has a built-in transformer designed to adjust the impedance of the speaker voice coil to the output of the radio receiver.
  The cord used to connect the loudspeaker to the radio receiver is the CD-314.
  Has a JK-33 input jack which mates with PL-68 plug.
  The LS-3 Loudspeaker was used during WWII with a variety of US Army Signal Corps receivers, such as the BC-189, BC-312, BC-314, BC-342, BC-652, BC-224 and BC-348, and used on into the 1950's. Much used in ground installations, since its use inside aircraft would have been reduced, where headphones were the preferred method for receiving audio to the crew. LS-3 is used with receivers, sound systems and paging systems designed in the standard designated by US ARMY SIGNAL CORPS.
  
  TECHNICAL CHARACTERISTICS:
  
  Impedance: 8,000 ohms.
  Speaker size: 6 in. (15,24 cm.)
  Transformer: Primary: 8000 ohms
  Secondary: 3.2 ohms 270 – 3000 Hz 1 watt.
  
  WEIGHT AND DIMENSIONS:
  
  Weight: 9 lb. ( 4,08 Kg.)
  Dimensions: 8.1/4 X 8.1/4 X 5.1/4 (in.)
  20,96 X 20,96 X 13,34 (cm.)
  
  Reference: TM11-487I
  
  .......... Alexandre Ricardo Baptista, Sao Paulo - Brazil, 30th of January 2019
  
  

A0529