UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - 3-valve reflex 1925 kit?

PJL · 1st Jun 2021, 2:20 pm

These early Ormond variable condensors are not logarithmic and of pretty low capacitance, about 120pF fully meshed. I am looking at a scrap IF transformer as a possible for the RF transformer. That just leaves the plug-in coils but I think I have some but doubt they will be the correct values.

Other than regeneration the only method of controlling the gain would be by using the filament rheostats. These are very small and I suspect they may simply be a carbon block with a screw down terminal. Have to see if that works with PM series valves and varying V1 filament is also going to reduce the audio output power.

1st Jun 2021, 2:20 pm	#5
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: 3-valve reflex 1925 kit? These early Ormond variable condensors are not logarithmic and of pretty low capacitance, about 120pF fully meshed. I am looking at a scrap IF transformer as a possible for the RF transformer. That just leaves the plug-in coils but I think I have some but doubt they will be the correct values. Other than regeneration the only method of controlling the gain would be by using the filament rheostats. These are very small and I suspect they may simply be a carbon block with a screw down terminal. Have to see if that works with PM series valves and varying V1 filament is also going to reduce the audio output power.