JVC GY-HM750CHU Instructions Manual page 125

[PHONES] Terminal
Audio output from the [PHONES] terminal can be selected
using [Audio Monitor] in the [A/V Out] menu (A Page 93) as
well as the [MONITOR SELECT] switch on the camera
recorder.
The different combinations of settings that are output from
the [PHONES] terminal and monitor speaker are as follows.
[MONITOR
[Audio
SELECT]
Monitor]
Switch
Settings
Settings
^
[CH-1]
[BOTH] [Mix]
[Stereo]
^
[CH-2]
[PHONES]
Terminal
Speaker
L R
CH1 CH1
CH1+CH2 CH1+CH2
CH1 CH2
CH2 CH2