help spec'ing a PT...

[HTH]

ok, I need a new PT for my '76 Marshall Superbass, I know some of the specs but need help on how to spec the HT tap.

If I were to spec 150-0-150, that's a center tapped HT winding - how do I calcualte the DC Voltage after the bridge rectifier converts the voltage?

The other taps would be...

heater winding - 6.3vac @ 7A (four EL34s and three ECC83s)
bias winding - 50vac

Cheers... Ian

[bob p]

Roughly speaking, you need about twice as much voltage. ie: 300-0-300 or thereabouts. Maybe someone else can offer an exact answer.

All things considered, if you're talking about the restoration of a collectable vintage amp, you might just want to go to a place like Mercury Magnetics and buying a proper drop-in replacement instead of trying to spec a generic transformer and then cobble up your chassis to make it fit. It will cost more, but you'll be able to buy exactly what you will need.

OTOH, if you want to go through the paces of specing-out a power supply, you might want to google for Duncan's power supply designer.