[egerton]

Having got my Bestone TRF working quite nicely, I'd like to dispense with the lamp limiter and find an integrated solution to power. It's a midget set so no room for a transformer so I am turning my attention to a capacitor dropper and wondered if a full wave bridge to supply DC to the set is better than a cap. drop alone. I'm considering the 2 comments I received in another thread about this subject. I am concerned by the statement in Chris's reply ..the whole set will be up at half mains or so. Is this more risky than a cap. dropper alone? The set has a 'live' (connected to neutral) chassis anyway.

As always any comments welcomed. Paul

Provided that the heater load is >>HT load it will work, but if the heater rms volts are correct, the HT dc will be a bit off, which may or may not matter. You could feed the whole set with positive dc by using a bridge rectifier with a series capacitor on the ac input, but then the whole set will be up at half mains or so.
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Capacitive droppers really need a symmetrical load, otherwise you will get a badly distorted waveform.

Probably the best way to get a transformerless radio to work with a capacitive dropper is just to wire a bridge rectifier around the set; so its rectifier, as well as the valve heaters, will be passing current on both half-cycles.
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Julie {formerly known AJS_Derby}