Can someone help me understand this transformer?

[blearyeyes]

Can someone help me understand this transformer? 
It has 5 input wires marked 0v~115v~SCN And 0v~115v

Why 3 wires for the 18v and 2 wires for the 9v secondaries?
The difference between 18v~0v~18v and 0v~9v has me confused.

It's an R type transformer:

Input Voltage:
International universal voltage  0～115V,  0～115V , Shielded wire (5 lines)

output voltage:
AC 18V～0V～18V (0.5A 3 lines)
0～9V (0.3A),   0～9V (0.3A),  0～9V (0.3A), 3 groups (6 lines) 

Output Power:30W

Size:79×68×40（mm）

[alanp]

Another way of thinking of the 18V-0V-18V outputs is to consider it a 36V winding with a center tap, if that helps.

I could be wrong.

[blearyeyes]

That's what I thought as well...

So then the two 18v outs would share a ground, be out of phase and not be isolated?

My brain hurts...

[alanp]

You're not the only one. My first instinct would be to make a +/- 15VDC bipolar psu with it, but for guitar pedals that is only useful for the Infinitphase.