HT/LT Battery Eliminator converts Vintage battery Radio sets to 230V, £29

Fits into the space of a EverReady B126 90V battery

HT and LT Battery Eliminator to convert vintage battery Radio sets to 230V mains. The eliminator, is designed to replace the now long unobtainable HT battery AND the LT batteries that were used in many valve portable sets of the 1950's and early 60s. It will fit into the space for, and indeed the casing of, an EverReady B126 90V battery. The Eliminator provides an HT supply (see table below) and a regulated LT supply for the filaments. You can order the LT voltage from 1 to 8V as required, normally I would build to 1.4V. as this is the specified heater voltage for most single cell battery valves. The HT voltage is unregulated (but smoothed) the actual voltage is not very critical as battery sets were designed to cope with a reducing HT voltage over the life of the battery. The unloaded power consumption is less than 1 Watt.

I can fit a buck converter for the same price, instead of the LM317T linear regulator this will supply up to an Amp of LT in the range 1.4v to 3v (adjustable), the downside of this is, it is a switching part and can introduce some RF noise, but in practice I have never found this to be a problem on older 1,2 or 3 valve 1920s TRF sets with 2V heaters.

HT Volts	LT Volts	Max LT Current	LT ONLY version
140v	1v..12v	160 mA	320 mA
120v	1v..10v	160 mA	320 mA
90v	1v..8v	200 mA	400 mA
68v	1v..6v	315 mA	630 mA
45v	1v..5v	400 mA	800 mA

Email or phone 0788 4425213 your HT/LT voltage combination requirements.
The LT side can supply the maximum current specified above (unless buck converter fitted) which is suitable for most sets that use a dry battery for the valve heaters, sets with a rechargeable lead/acid battery usually take a higher heater current, Pye/Vidor/EverReady etc. sets with a valve line-up of typically DK96,DF96,DAF96,DL96 will work fine with 90V HT 1.4V LT, I can check your set for suitability before ordering I have most schematics in my collection and am happy to send to you. The 230V mains input, HT and LT connection are all made using screw terminals, so no soldering is required. The Eliminator provides full isolation from the mains input, and will allow the set to pass PAT tests. The mains input Live/Neutral can be connected either way round, it does not matter. Be aware that mains voltage is present at a few points on the PCB underside, so care should be taken when mounting, using stand off bushes on the mounting screws or making other provision for the board's underside to be insulated from the set's case or chassis (not usually a problem with a wooden case!). There is no mains voltage accessible from the component side apart from the connector screw terminals. The PCB dimensions are 92mm x 64mm x 37mm high, by comparison, a B126 battery is 2.5 x 4 x 2" (102 x 64 x 51 mm) and a B141 is 198 x 119 x 37mm. The LT and HT supplies are electrically isolated from each other. I usually wire these up with an inline switch (table lamp switch) in the mains cable (not supplied) so no alteration is required to the set for a mains on/off switch, suitable made up cables can be rescued from table lamps as found in charity shops etc. for around £2. The batteries are shown for illustrative purposes only, these are the types or similar that this unit replaces.
I can also build HT only or LT only versions with £10 off the price i.e. £20.
Postage is £3 to the UK, See table above for international rates, although be aware that only 230VAC models are currently available!

92 x 64mm fits into the space of B126 90V battery

Buck Converter version for LT current up to 1 Amp

Fitted to a PYE P144BQ portable battery set

Battery Eliminator on Soak test at maximum current

EverReady B126 90V HT Battery

EverReady AD35 1.5V Filament Battery