What's the difference between period correct trannies & the multi purpose ones?

[Twosteps]

Say I want to build a head from scratch so period correct dimensions are not a problem, if I have a sound of a certain circuit in mind would it still be best that I go for trannies for a specific model as advertised by many companies? Or does the vintage construction matter? I know that of course, theoretically it sure would work if I take the specifications of those trannies and get them custom wound(it's easier and cheaper than to order one from abroad here where I live) but is there some "mojo" lying in there somewhere that you shouldn't go with a multi purpose ones - keep in mind that it's still that vintage-y sound I want to achieve.

[jjasilli]

Vintage trannies and guitar pickups were wound in a more old fashioned way, with proprietary interweaving techniques, or perhaps even random ones.  Interweaving places the wire across the winding so upper layers don't dig in to lower layers; but also affects the magnetic field which may, in turn (no pun intended) affect tone.  Some modern makers have have carefully unwound vintage specimens to see the winding techniques, in order to copy them.  They may also try to use similar enameled wire and core material.  Modern windings tend to be more mechanically precise.

[Twosteps]

Ah, just like pickups, that clarifies it. Thank you very much.

[byoungblood]

Depends on what kind of an amp you’re talking about. I know offhand that McIntosh amps used specially wound transformers, but I would suspect that your typical guitar amp probably used whatever could be found at relatively low cost that met their design specification.