Transformer amp replacement

Jbailes

Member
2016-01-25 10:35 pm

Hello everybody,
I need some advice. My amp transformer AC/AC is dead (primary short-cut).
1/ it’s a standard laminated steel core transformer, Can I replace it by a toroidal or must I add some filtering component?
2/ the datasheet of my amp specifies -32/0/32V AC, I have the opportunity to buy easily at low price second hand toroidal. I found one -30/0/30Vdc and -35/0/35Vdc. Can I use one of them or theses specifications are too far from the origin? (Amplifier board component are 50V minimum)
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Primaries usually fail open circuit, typically due to a thermal fuse failing. A good primary on a large transformer can read very low resistance on a meter, just a few ohms. Its impedance at AC is much higher of course.

A toroid is fine electrically as long as it can be made to fit although a good E I type can have advantages (mechanically quiet and more compact form)

Given a choice of a 30 or a 35 volt replacement I would go for the lower one. Voltages are always higher at light loading anyway. Make sure you pick a suitable VA rating for any replacement.