• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

confusing transformer connections

I recently acquired an old amplifier from a thrift store. It is an EL84PP driven by a 12AU7B. I'm planning on removing all the unnecessary stuff such as active EQ and radio receiver circuit but the output transformers connections is puzzling. The primary side of the OPT's have two red and one green leads. On one channel one red and one green is connected to the respective EL84 plates and the other red lead is grounded. On the other channel, the two reds are connected to plates while the green wire is grounded.

Is there is color code for older OPT leads or does it not matter at all? I turned the amp on and besides being really noisy it seems to playback music so I would guess that the OPT's are working.