Combo Amp and Extention Speaker

[TIMBO]

Hi guys, I have a combo amp that has two speaker sockets.
One is marked 7.5 ohms "amp speaker" and the other 15ohm "EXT. speaker.

The sockets are connected in parallel.
The combo speaker is 15ohm.
The original OT is stuffed and I have replaced it with an OT that has 4,8 and 16ohm taps.
I don't know what the original OT tap was used.

What tap do I use??

[sluckey]

Use the 16Ω tap with that 15Ω speaker.

[TIMBO]