What does current rating mean on a PT.

[tribi9]

What does it mean to me if a PT puts put 310-0-310 rated at 70 mA vs a PT that puts 310-0-310 but is rated at 150 mA?

Is the current rating the maximun mA all my tubes combined should be drawing?


Sorry for all the questions but sometimes Google is not your friend.

Cheers and many thanks.

[tubeswell]

What does it mean to me if a PT puts put 310-0-310 rated at 70 mA vs a PT that puts 310-0-310 but is rated at 150 mA?

The current rating on each winding is about how much current is able to be 'safely' drawn through that winding without it overheating/smokin'. Usually thicker copper = higher current rating.

Is the current rating the maximun mA all my tubes combined should be drawing?.

Yes - well at least as far as HT windings are concerned anyway. For heater windings, there isn't really a big variation in current draw, it is is fairly constant

[j-po]

Is it continuous rating is another matter. usually we want a minimum of 150mA for a pair of El34 or 6L6 and 100mA for EL84 or 6V6. Short current peaks will overload the PT temporarily but the thermal capacity of the windings absorb the extra heat.