[Hallicrafters] Ref: SX-28

[Walt Cates]

Carl, Nick, and Bob got it right. The impedance of the primary and secondary( s ) are dependant on the flux density in the core of the transformer. As you lower the voltage below the design center, Z takes a sharp decrease. When Z goes down, current goes up. This can be disastrous for an old "soft" transformer. The SX-28 states that it is to be operated between 110 and 125 volts.

Best Regards, Walt Cates, WD0GOF, http://www.myhamshack.com/WD0GOF/<http://www.myhamshack.com/WD0GOF/>