Proel AMP03 - Manual (Page 11)

CONSTANT VOLTAGE LINE.
If you’re using a constant voltage line, connect either the 100V to the “+”
side of speaker system, and connect COM to “-“ side of the speaker
(fig. 2 ref. 4).
• Speakers should have a transformer of the same voltage
developed by the amplifier.
• Speakers power sum should not be higher than the amplifier
maximum output power.
3. Priority Function
When PRIORITY (fig.2 rif.3) terminals are in short-circuit, MIC2, AUX
and PHONO inputs are muted and MIC1 has output priority.