[Amps] Berkshire

[Tom W8JI]

> Oh, I almost forgot: Thinner wire is more expensive by 
> weight than
> thicker one, and you need the same weight of wire for both 
> versions of
> the transformer. So there is an additional cost advantage 
> (even if a
> slight one) to partially offset the higher cost in filter 
> caps.
>
> When looking at commercial amps, it seems that they have 
> generally moved
> from doublers to bridges over the last few decades. I 
> would guess that
> this is related to increased automation in transformer 
> manufacture.

It's probably related to customer opinion.

You forgot something else. Because there are half the turns, 
layer to layer insulation can be reduced and this means more 
copper and less paper. The peak voltage at one end of the 
winding is just as high as in a bridge, but the voltage 
across the entire winding, from the side that ties to the 
caps, and from layer to layer is half as much. Less paper 
also allows for better thermal characteristics.

My guess is doublers mostly got a bad reputation because 
people used them to "double power" from small TV 
transformers, running the same current that the transformer 
was supposed to supply in a regular full wave. They really 
aren't bad.

73 Tom