UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - DC Mains on Pre-War TV's

TonyDuell · 11th Apr 2021, 3:51 pm

I seem to remember that in that ACE radiogram, the radio/amplifier was an AC/DC mains design, heaters in series, rectify the mains to get the HT+. So the converter only supplied the turntable motor. Also there was no rectifier for the anodes of the converter valves, there didn't need to be as the converter was only used on DC mains.

Did any company ever make a turntable where a 50Hz or 60Hz mains synchronous motor was powered from a transistorised converter, allowing it to be used in Europe or America? The reason I ask is that I have a Tektronix PDP11 (by which I mean a Tektronix computer with a DEC PDP11/03 or PDP11/23 CPU board in it) where the 8" floppy drive spindle motors are powered by a transistorised circuit running off the 350V DC in the switch-mode power supply. Thus the drives run at the right speed with no modifications no matter what the mains frequency is.

11th Apr 2021, 3:51 pm	#11
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: DC Mains on Pre-War TV's I seem to remember that in that ACE radiogram, the radio/amplifier was an AC/DC mains design, heaters in series, rectify the mains to get the HT+. So the converter only supplied the turntable motor. Also there was no rectifier for the anodes of the converter valves, there didn't need to be as the converter was only used on DC mains. Did any company ever make a turntable where a 50Hz or 60Hz mains synchronous motor was powered from a transistorised converter, allowing it to be used in Europe or America? The reason I ask is that I have a Tektronix PDP11 (by which I mean a Tektronix computer with a DEC PDP11/03 or PDP11/23 CPU board in it) where the 8" floppy drive spindle motors are powered by a transistorised circuit running off the 350V DC in the switch-mode power supply. Thus the drives run at the right speed with no modifications no matter what the mains frequency is.