speaker connected to No 19 set

Robert Bergeron · #1 14-02-21, 02:47

Gents , is there a way to connect a speaker to the WS no 19 set in place of headsets ? The idea is to show visitors real radio traffic without having to hand over a set of headsets and microphone .

Bruce MacMillan · #2 14-02-21, 19:30

quite a few people have used a speaker either connected directly to pin 4 of PL2A or through a control box. The thing is the audio output impedance of the 19 set is 100 ohms. Most speakers are around 3-8 ohms. This mismatch will result in low audio. You can use an audio matching transformer to match your speaker impedance. Connecting it to a 19 set snatch plug means you don't have to modify the set. It looks like you have a #3 control box so should have a spare drop. Canada actually had a need for a speaker and had a quote from Pye but never followed through.

Robert Bergeron · #3 14-02-21, 20:51

Thanks Bruce . 100 Ohms . That’s all my radio / tv tech will need to know to make my snatch plug . Very useful info .

Bruce MacMillan · #4 24-02-21, 08:00

researching for another user on another website I came up with a Hammond 144B transformer. This is 200 ohm center tapped to 3.2 ohm. Using 1/2 of the primary you'll have a perfect match. You can try Electrosonic or Mouser, etc to source the part.

CWO (ret) Gilles Aubé · #5 25-02-21, 16:34

Mon col, in my time with the 19th set we used a speaker from the Tanoids
set from the gun and it worked perfectelly.
BON tir.
Gilles

Robert Bergeron · #6 27-02-21, 13:59

Thank you Chief Aubé .

Chris Suslowicz · #7 27-02-21, 21:35

I think the Tannoy 'gun control loudspeaker' is probably a good solution, and if you need a volume control look at the Control Unit 190 as used on the Sexton for how that was set up. (I think I've got this right.)

Chris.

Robert Bergeron · #8 06-05-21, 03:04

OK friends , i have this now . How do i connect it to the No 19 set as a speaker ? The simpler the solution the better . Notice the lower buttons ( phone wire connection ? ) are identified as connecting to the No 19 . The upper ones are identified as «*line*» . How about if i connected it to a remote then connect the remote to the set with the snatch plug ? Will that work ? Thanks .

Robert Bergeron · #9 08-05-21, 03:03

How about i connected the speaker to a remote hence the remote to the snatch plug on the control box of the wireless set ?

Robert Bergeron · #10 14-05-21, 04:29

Interesting second paragraph . What does it mean ?

Chris Suslowicz · #11 14-05-21, 12:15

Quote:

Originally Posted by Robert Bergeron

Interesting second paragraph . What does it mean ?

It means they used the intercom amplifier to drive the loudspeaker once they were set-up in position. (More power available than from the 'A' set audio output stage.)

You should be able to drive that at a reasonable level from the 'A' set, just use about a 70 ohm resistor in series with one of the loudspeaker terminals and connect it to the 'phones' output in a droplead or the terminal block in the control unit. Add more series resistance if too loud, reduce if not loud enough, but 70 should be enough to keep the 'A' set safe from overload.

I'll give it some more thought later. (There may be diagrams!)

Chris.

Bruce MacMillan · #12 14-05-21, 15:41

apparently it was something that was done but not an official mod.

Chris Suslowicz · #13 14-05-21, 16:46

That may well be the origin of Control Unit 190.

UK War Office saying "Nothing official exists, local bodges only." and Canada thinking "OK, there's a need for this, let's do it properly".

Chris.