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| Replacements for old Valve Radio Power Supplies |
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| Connecteur:
Power supplies are a notorious point of failure, particularly in the oldest radios. Back in those days, copper wire was often stretched to make it fine enough for transformer windings. Because the quality of the copper varied, the resulting wire would be of varying thickness, sometimes disintigrating from corrosion or breaking from thermal expansion. Salvaged transformers are increasingly hard to find, therefore a manufactured equivalent or solid state power supply might be the best option. It depends on the owner's preference for the level of authenticity they want to preserve. |
| GlennSprigg:
Yep.. that can & does happen. Audio output transformers are notorious for failing! They are/were of such low construction quality, that 80% of the old originals now fail. To a 'restorer' that is not insurmountable. Simply 'ReWind it'... As a Side-Note of interest... many years go I ran a 200-Amp mains 3-phase supply to a remote (1 km away) main switchboard. In the end, it was 15 feet short of the Termination!! We stretched it with a Tractor, reducing it by a 'few' amps hahahaha... Shit happens!! 8) |
| bd139:
You can get a wide variety of HT voltages by using two cheap low voltage transformers back to back and doubler circuits. Much cheaper than buying hammond stuff! Say you need 6.3v heater and 200v HT: Fat 120:6 first transformer. Pull the heater winding off it. Then attach a smaller 6:120 on it, use a half wave doubler and then use a C-R-C circuit with empirically determines value of R based on the load to drop it down to the voltage you need. This is near infinitely flexible and damn cheap! |
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