This is certainly an artefact from WWI


But what is it?

My guess is that it was either used in conjunction with a trench set spark receiver or to aid listening-in to enemy telephone communications.

Two pairs of input terminals are provided, being marked "HF" and "LF", with two sets of terminals for headphones

The volume (or gain) was changed by varying the filament voltage and the tapping on the input coils.

Was it used to amplify British transmissions or those of the Germans? Click to see some details of this?

The panel, alas is now just as you see it. Probably sold as war-surplus around 1920, it has been stripped of its tuning coils, LT and HT switches, and wiring (and of course the valve). Why the double military arrowheads? Ian Gallimore in Toronto tells me that the double arrowhead indicates the panel was sold as off as surplus.

Alister Mitchell up in GM'land kindly provided the following....

"It is one of a batch of 1250 listed as Amplifier C Mark IV and IV* made by Newton and Wright between August 1918 and March 1920 at a cost of £14.25 (£14 5/-) each, or about £260 in today's money.
I attach a
description dated 1921 and a circuit - sorry the quality is a bit poor but the paper has oxidised considerably, despite being kept in the National Archive! Below are better pictures converted from the above.

It was supplied as part of the following stations:
W.T. Set, Light Motor Mk I, I*, Spark, 1.5KW
120W CW Set in Crossley Car
500W CW Set in Motor Car
60W CW Set
CW Receiver Mark IV

From what I can make out, it's purpose was either as an AF Amp feeding headphones (switch in LF position) or as a detector and AF Amp (switch in HF position). When detecting, the first valve (they were all type R) seems to have been fed from a mixture of signal and BFO. At least, that's how I would translate the description!"

I've put it down as "perhaps restorable", given a wooden case, some valves, a couple of switches and a few coils?

 First, below is a modern drawing, then second some drawings from the period




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