power transformer specs

[dscottguitars]

Hello,

I noticed that some tube amps, Fender Champ, have power transformers with ~660v @~100mA and others, Bassman, 700v @ ~400mA.

My question is this:

Can any transformer that satisfies a voltage requirement on the plate work? Like a smaller, 440v transformer with higher current. I am confused why the voltages would be stepped up so high to use only 305V on the plate for a Fender Champ.

Thanks Gurus...

 

[Richard Ellis]

There is an upper limit of course that a tube can run on the plate....You can run tubes on a considerably lower value of plate voltages, it all depends on plate "curves". This is how you design a tube amplifier.....by selecting bias points with tube "curves". One selects a point along these curves which is most 'linear'....it's a designers call.


_______________________________________________________Rick.........

 

[DF96]

In some cases the transformer secondary will be centre-tapped, so 660V is actually 330V.