power transformer suppliers

[JBaker]

Greetings!

i'm wanting to build a power supply for my synth project...the circuit
calls for a transformer: 110-120vac primary, 36vac 4amp secondary...i
have looked and looked, but can't seem to find a source for this
item...is this type of thing generally hard to find? expensive?  am i
looking in the wrong place (Radio Shack, Mauser, Digikey, Halted, misc.
online surplus suppliers)??

Thanks,
Jeff