01-12-2016, 03:30 PM
The Brimar 1D6 arrived last week and has been fitted in the set, no modifications required. This set is designed to work on 100 to 120 volt AC supplies, that's the way it was in France in the old days, 230V now. The 0.3amp heater chain adds up to 75 volts including the dial lamp so 40 volts has to be got rid of by some means. A capacitive dropper is out of the question because it will have a value of something like 20microfarads if the set is to be used on 115 volts.
However, it's good to hear about other ideas from other radio engineers and Trevor has come up with a good one. Convert the set to 230 volts. The heater dropper will then become the more manageable value of just over 4microfarads. Better still, a separate capacitive dropper for the HT supply, this will determined after the HT current has been measured.
At the present time for the heater chain ballast I've fitted a RadioSpares "polomint" type of resistive dropper, that's definitely not nice because of the heat dissipated from this component.
Check out the dropper resistor in the attachment.
Geordie McBoyne.
However, it's good to hear about other ideas from other radio engineers and Trevor has come up with a good one. Convert the set to 230 volts. The heater dropper will then become the more manageable value of just over 4microfarads. Better still, a separate capacitive dropper for the HT supply, this will determined after the HT current has been measured.
At the present time for the heater chain ballast I've fitted a RadioSpares "polomint" type of resistive dropper, that's definitely not nice because of the heat dissipated from this component.
Check out the dropper resistor in the attachment.
Geordie McBoyne.
