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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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9th Oct 2018, 10:56 pm | #41 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
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Re: Pilot Little Maestro Pilot Lamp Conversion
The problem with using X capacitors as voltage droppers is the self-healing and consequent loss of capacitance. Every switch-on surge (a cold valve heater, or a discharged capacitor, is almost a dead short circuit) tends to weaken the capacitor a bit until eventually there is insufficient power available and the circuit begins to misbehave, requiring replacement of the capacitor.
The company I used to work for did some tests and found it was better just to use a standard 400 or 630V capacitor, with a fusible resistor to limit the switch-on surge.
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10th Oct 2018, 10:43 pm | #42 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,567
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Re: Pilot Little Maestro Pilot Lamp Conversion
What's happened to Kings? We still don't know for sure what the correct valve line-up is.
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11th Oct 2018, 3:25 am | #43 | |
Heptode
Join Date: Mar 2017
Location: Cedar Grove, Wisconsin, USA.
Posts: 823
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Re: Pilot Little Maestro Pilot Lamp Conversion
Quote:
I'm surprised that the # 21 post was so incorrect! I'm rather familiar with this valve line-up. It seems that Brimar was the main supplier of the US type valves used in the British built radios. This really was an informative and interesting thread! |
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