Roland JC-50 - missing third speaker cable connection

[jmeager]

Hi

I am new here and have minimal knowledge of electronics (sorry).

I have a Roland JC-50 that I love the sound of.

The speaker has three cables connected to it from the amp head.

Unfortunately one of these has detached from the head.

The amp / speaker both still function, but there does seem to be more "noise" than before.

I am assuming this third connection was some kind of ground?

Where should I reattach it?

Sorry for this relatively vague question.

[Jazz P Bass]

The schematic does not indicate a 'speaker' connection from the main board.
What it does indicate is the 'headphone jack'.
That has three connections.
The speaker comes off of the headphone jack (a normally closed contact)