UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - When did Valve heaters change from 4v to 6.3v

dragonser · 10th Feb 2018, 4:58 pm

HI,
sorry if this is a stupid question, but does anyone know roughly when valve heaters were changed from 4 volts to 6.3 volts ?
the reason I ask is that I have an old mains transformer with the usual ht windings ( 340- 0- 340 ) , but it has two 2-0-2 heater windings and one 12v winding.
I was thinking of making a HV bench power supply with it, but out of interest I wondered how old it might be ?
I'm assuming the 12volt winding might be for a bias supply ?
I can post a picture if it would help..

10th Feb 2018, 4:58 pm	#1
dragonser Heptode Join Date: Aug 2009 Location: Carshalton, Surrey, UK. Posts: 734	When did Valve heaters change from 4v to 6.3v HI, sorry if this is a stupid question, but does anyone know roughly when valve heaters were changed from 4 volts to 6.3 volts ? the reason I ask is that I have an old mains transformer with the usual ht windings ( 340- 0- 340 ) , but it has two 2-0-2 heater windings and one 12v winding. I was thinking of making a HV bench power supply with it, but out of interest I wondered how old it might be ? I'm assuming the 12volt winding might be for a bias supply ? I can post a picture if it would help.. __________________ Regards Peter B