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Audio and Video Talk
Valves / Vacuum Tubes
How to design a Power Transformer for a Push-pull tube amplifier?
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<blockquote data-quote="Ampdog" data-source="post: 194709" data-attributes="member: 144"><p>If I may ...</p><p></p><p>In Pretoria and certain parts of Jo-burg the mains can go to 245V. In Pretoria it is regularly at around 240V. Thus a 'universal' power transformer for RSA should really cater for a 10 - 0 - 210 - 230V primary, or 10 - 0 - 220 - 240V.</p><p></p><p>BarryD' (sorry for going OT),</p><p></p><p>Ah! Good old 56 valves (going back to 1950 in my life). I am just a little worried of the +160V you operate the heaters at. Perhaps the Googling skills of others are better than my own, but I cannot find the max. cathode-heater voltage for the 56 (or 76 for that matter). Somewhere halfway between 176V and ground would make me feel more comfortable, like replacing the 100K resistor in the voltage divider by a 33K. But perhaps others can correct me on this. The oldest data I have is the H-K voltage of 200V for the 6SN7 and such; so possibly safe. </p></blockquote><p></p>
[QUOTE="Ampdog, post: 194709, member: 144"] If I may ... In Pretoria and certain parts of Jo-burg the mains can go to 245V. In Pretoria it is regularly at around 240V. Thus a 'universal' power transformer for RSA should really cater for a 10 - 0 - 210 - 230V primary, or 10 - 0 - 220 - 240V. BarryD' (sorry for going OT), Ah! Good old 56 valves (going back to 1950 in my life). I am just a little worried of the +160V you operate the heaters at. Perhaps the Googling skills of others are better than my own, but I cannot find the max. cathode-heater voltage for the 56 (or 76 for that matter). Somewhere halfway between 176V and ground would make me feel more comfortable, like replacing the 100K resistor in the voltage divider by a 33K. But perhaps others can correct me on this. The oldest data I have is the H-K voltage of 200V for the 6SN7 and such; so possibly safe. [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
How to design a Power Transformer for a Push-pull tube amplifier?
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