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Old 27th Dec 2016, 3:04 pm   #94
indigo.girl's Avatar
Join Date: Apr 2016
Location: Loughborough, Leicestershire, UK.
Posts: 754
Default Re: My first valve radio project - Philips 462A

Ah, I see - in all cases 240V is being applied to the transformer each time (being the UK supply from the mains) and the disc position denotes the ideal place for the supply voltage to be added across the transformer depending on the mains supply you have. This should normally be the 245V position for UK. When I move the dial to the 200V setting 240V is still being applied across the transformer windings but across fewer of them, and perhaps bypassing a shorted turn, hence a better output. In the case when I set the dial to 145V this means I am putting the 240V across an even smaller section of the windings and hence over load and vibration.
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