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David Simpson · 24th Jan 2019, 9:58 pm

Well, 1920's TRF's don't usually draw very much valve Ia, and if an SG valve is used then Is would be negligible. Likewise Ig should be negligible. My two TRF's only require 60V Vs, and the other HT's are near enough 90,120 & 150V. So three wee mains T/F which will handle approx. 10mA Isec. & their associated chokes & capacitors take up a fair portion of space available. For all the use they'll get, the two rechargeable battery packs could soldier on for years, if regularly checked & charged.
2V Filament supply could actually come from an original working glass Exide 2V accumulator. But my digital LV PSU is jolly handy & reliable for all my heater/filament requirements.
Meters - I've plenty just now. So will monitor all the HT currents & voltages. So once the panel layout is decided, and a hinged paxolin or aluminium panel cut, drilled & polished - then I'll get round to calculating multipliers, shunts & so on. Then fit rotary yaxley type selection switches, and other ON/OFF toggle switches etc. Plus Pots to fine adjust HT voltages.
Isn't electronicing fun ?

Regards, David

PS.Have you seen the cost of those modern digital Battery Eliminators from the States - a couple of hundred quid at least. My costs for all the above - NOWT ! Plus hours & hours of work in my wee office/workshop on frosty January & February days - I'll just have to force myself.

24th Jan 2019, 9:58 pm	#4
David Simpson Nonode Join Date: Mar 2008 Location: Aberdeen, UK. Posts: 2,857	Re: Homebrew Battery Eliminator Well, 1920's TRF's don't usually draw very much valve Ia, and if an SG valve is used then Is would be negligible. Likewise Ig should be negligible. My two TRF's only require 60V Vs, and the other HT's are near enough 90,120 & 150V. So three wee mains T/F which will handle approx. 10mA Isec. & their associated chokes & capacitors take up a fair portion of space available. For all the use they'll get, the two rechargeable battery packs could soldier on for years, if regularly checked & charged. 2V Filament supply could actually come from an original working glass Exide 2V accumulator. But my digital LV PSU is jolly handy & reliable for all my heater/filament requirements. Meters - I've plenty just now. So will monitor all the HT currents & voltages. So once the panel layout is decided, and a hinged paxolin or aluminium panel cut, drilled & polished - then I'll get round to calculating multipliers, shunts & so on. Then fit rotary yaxley type selection switches, and other ON/OFF toggle switches etc. Plus Pots to fine adjust HT voltages. Isn't electronicing fun ? Regards, David PS.Have you seen the cost of those modern digital Battery Eliminators from the States - a couple of hundred quid at least. My costs for all the above - NOWT ! Plus hours & hours of work in my wee office/workshop on frosty January & February days - I'll just have to force myself.