I am restoring my Raycophone 154PE and it uses a 6A7 instead of a 2A7 in the front end. Someone in the past has gone to the trouble of putting a little step up transformer in the filament circuit to take it from 2.5v to 6.3v. Also one dial light is 2v and the other 6. I wonder if this was standard practice in the old days. Perhaps 2A7’s were in short supply. See photos below...

The use of 2.5 volt valves in Australian radio manufacturing for mains receivers had all but ended by about 1934. Valves like the 2A7 and 2A5 (2.5 volt version of a 42 & 6F6) were only found in radios made during the 1933 & 1934 season. This probably accounts for their scarcity. A lot of the 2.5 volt valves series had 6.3 volt equivalents, the only difference being the heater voltage.

From about 1934 onwards most radio's manufactured were using 6.3 volt valves. The 6.3 volt standard came about due to the emerging popularity of car radios in the 1930's - the auto electrical systems of the day being 6 volts (or 3 X 2.1 volt cells in a car battery). I have seen instances where radio restorers have opted to change the power transformer to suit 6.3 volt valves in place of 2.5 volt types. If I were restoring the Raycophone I'd, for originality, revert back to the 2A7.

I agree that if possible, reverse engineering for originality is the best way to go.

Nice radio too. Raycophone was one of many brands that were uniquely Australian.

OK I'll put it back to original. I have a 2A7 but who sells 2.5v globes?

Altronics, 174 Roe Street, Perth.

http://www.altronics.com.au/p/s4042-2.5v-push-in-globe/.