Audio Amplifier
SIP9
+------+
++ 1| Input
| 2| GND (small signal)
| 3| Muting
| 4| Return 1
| 5| Return 2
| 6| GND (large signal)
| 7| Exit Output 2
| 8| Exit Output 1
++ 9| Vcc
+------+
No frequency to check