@odyopayl,
if you want to build this set amp, just get the circuit from decware, my amp uses ss rectifers in a voltage doubler from a120volts ac@500mA. with choke filters and big caps!
for the output transformer, they are wound from a 7/8in core, sqaure stack. primary has 5400 turns of #35 wire in three sections connected in series, secondary has 216 turns of #30 wire 2 coils wired in parallel! you can ask your favorite winder do this for you. btw, interleaving is like this, primary, secondary, primary, secondary, then finally primary. be dure to provide adequate inseulation between windings!
also, be sure all the E's go together, there should be a 10mill gap between the E and the I, a mylar plastic sheet may be used.
using a bobbin is the only way to wind this output traffo!
hope this helps!