The amplifier is based on a low-noise operational amplifier (TL072), which can be replaced with other compatible op-amps such as NE5532, OPA2134, OPA2132, and more, depending on your preference.
Thanks to its independent power supply (battery operation), this amplifier also helps extend the playback time of portable devices by reducing their internal load.
Specifications:
Power Supply: 6F22 battery (9V)
Optional External Power Supply: 9–24 V DC
Current Consumption: < 10 mA
Notes:
For desktop use, the amplifier can be powered from a single-polarity external power supply (9–24 V DC).
The external supply should be linear, with low ripple, to avoid introducing unwanted noise into the audio signal.
During assembly, solder the jumper located between U2 and C1, C3 first (see assembly diagram).