30-07-2011, 06:29 PM
Well done on winning that Joe.
An interesting set, which came out immediately after WW2, launched in 1946, using low consumption valves. The HT consumption is only 9mA, and the LT 250mA. Expensive when first launched - £14.14s.0d plus 33% Purchase Tax, but reduced in price in April 1949 to £13.11s.4d, including batteries, (PT extra).
From serial No 13/15001 there were several modifications, which included altering the battery wiring so that separate LT and HT batteries could be use - apparently due to difficulties in obtaining combined batteries. (Unlike Ever Ready, Vidor etc, who had a vested interest as battery manufacturers, and sold radios as an aid to that, Bush on the other hand, will have had a vested interest in trying to ensure economical battery consumption).
I think that combined batteries were a similar con trick to the present day situation with some printer ink cartriges which are often combined in one unit, so if magenta runs out but you've got plenty of cyan and yellow left, tough - the whole cartidge has to be replaced, and often, you can't print black either till a new colour cartidge is installed. Same I guess must have applied to combined batteries, if the LT ran down and there was some life left in the HT. Valves are quite happy to work on much lower HT voltages that a fresh battery - say down from 90V to 60V, but soon fade when the LT voltage drops.
You're right about the very large 2uF smoothing cap. Unlike in a mains set, where it might need a high ripple rating to smooth the AC, that doesn't apply in a battery set, and that is recognised by the low value of 2uF. A modern replacement will be puny by comparison, so no doubt you'll need to stuff the old one, with oodles of space to spare!
Enjoy the set Joe- it's polished up very nicely!
David
An interesting set, which came out immediately after WW2, launched in 1946, using low consumption valves. The HT consumption is only 9mA, and the LT 250mA. Expensive when first launched - £14.14s.0d plus 33% Purchase Tax, but reduced in price in April 1949 to £13.11s.4d, including batteries, (PT extra).
From serial No 13/15001 there were several modifications, which included altering the battery wiring so that separate LT and HT batteries could be use - apparently due to difficulties in obtaining combined batteries. (Unlike Ever Ready, Vidor etc, who had a vested interest as battery manufacturers, and sold radios as an aid to that, Bush on the other hand, will have had a vested interest in trying to ensure economical battery consumption).
I think that combined batteries were a similar con trick to the present day situation with some printer ink cartriges which are often combined in one unit, so if magenta runs out but you've got plenty of cyan and yellow left, tough - the whole cartidge has to be replaced, and often, you can't print black either till a new colour cartidge is installed. Same I guess must have applied to combined batteries, if the LT ran down and there was some life left in the HT. Valves are quite happy to work on much lower HT voltages that a fresh battery - say down from 90V to 60V, but soon fade when the LT voltage drops.
You're right about the very large 2uF smoothing cap. Unlike in a mains set, where it might need a high ripple rating to smooth the AC, that doesn't apply in a battery set, and that is recognised by the low value of 2uF. A modern replacement will be puny by comparison, so no doubt you'll need to stuff the old one, with oodles of space to spare!
Enjoy the set Joe- it's polished up very nicely!
David
