Snelgrove Co. Toronto Canada
Marked SO-17-4 12V. 75’C
Height 57mm. Diameter 41mm.
Solid construction copper outer shell secured by 3 slotted screws, connection via the 11 pin valve style base plug (with orientation notch)
Removing the copper coloured cover reveals an inner chromed cylinder which itself has a lid, removing that reveals four pairs of pin sockets to accommodate 4 separate HC49 type crystals. The chromed cylinder is heated by a wound copper element, presumably to 75’C as is marked on the outside.
We obtained these as part of a lot of surplus stock, they were originally supplied by the Snelgrove Co. of Canada to one of the old Decca sites in London.
Unfortunately we don’t have any other information on them other than the basic specifications given above.