Think about tackling the problem in a slightly different manner. Use 1 secondary of an AnTek AS-1206 for tube heating and 1/2 wave parallel multiply the 2nd secondary to derive the bias rail.
1/2 A. rated Schottky diodes will be "perfect" in the multiplier, given their low forward drop and "noise free" operation.
BTW, the multiplier schematic is for a positive rail. So, reverse the shown diode polarity.
1/2 A. rated Schottky diodes will be "perfect" in the multiplier, given their low forward drop and "noise free" operation.
BTW, the multiplier schematic is for a positive rail. So, reverse the shown diode polarity.
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Thanks guys. I am aware of those solutions. I prefer the solution in my OP.
Question: Some toroidal power transformers come with a warning that all windings must be used, either in series or parallel. Why is that?
Specifically, If I have a 120/6V toroidal, can I derate the secondary to half current and use one of the 120V primaries as a secondary? That would get me both 6.3V heater and bias voltage in one transformer.
Question: Some toroidal power transformers come with a warning that all windings must be used, either in series or parallel. Why is that?
Specifically, If I have a 120/6V toroidal, can I derate the secondary to half current and use one of the 120V primaries as a secondary? That would get me both 6.3V heater and bias voltage in one transformer.
Dual-winding toroids are bifilar would. You do NOT want to use one of the 120V windings as a primary and another as a secondary. It *could* short between turns and you’d get sixty-hertzed.
All secondaries must be used to get full power rating. You can get away with using them independently, as long as the voltage differential between them isn’t any more than it would be if you just put them in series.
I would just get a 6 or 12 volt toroid for the heaters, and add another secondary for the bias. Or buy something oversized VA wise for the bias voltage, and add heater windings. That may be easier since you can just use bell wire with that few turns and not worry about taping the trafo.
All secondaries must be used to get full power rating. You can get away with using them independently, as long as the voltage differential between them isn’t any more than it would be if you just put them in series.
I would just get a 6 or 12 volt toroid for the heaters, and add another secondary for the bias. Or buy something oversized VA wise for the bias voltage, and add heater windings. That may be easier since you can just use bell wire with that few turns and not worry about taping the trafo.
But wouldn't that short also be a problem if they are in series for 240V mains? Each twin turn of the 2 windings is/are 120V apart. In fact, when using one as an isolated secondary, a short wouldn't draw any current, it would just maybe zap someone
Yes, if I mess with it it's easier to add a 6V secondary. Few turns and heavier wire.
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