Proel AF4 - Manual (Page 6)

Front panel description
1. POWER switch and LED
2. Frequency/level LED indicator
3. Filter bypass master switch
4. Frequency and filter attenuation settings
Rear panel description
1. IEC standard AC power supply socket
2. Fuse-holder
3. 24V DC emergency power supply terminals
4. Balanced 6.3mm (1/4”) output jack connector
5. Balanced 6.3mm (1/4”) input jack connector