Radio Shack 1:8 step up transformer lead guide?

[Marc.yo]

I can't figure out the leads on this thing....which is which?


I'm doing this pedal. I know it's simple but the transformer is tripping me up...there's an extra lead.....I know, but it's my first time working with a transformer.

[soulsonic]

FYI, it's not a step up, it's a step down.
Anyway, wire like this: Green to 9v, Blue to Collector of transistor. Ignore the Black wire, it's a center tap and not used in that circuit.
Red and White got to the speaker - it really doesn't matter which terminals unless phase is a big issue (it's not in this circuit).

I've used that same transformer in a 12K5 low-voltage tube amp recently with good results. It's really dirty sounding in a way that's good with guitar.