Micro power amplifier for line recording
I wanted to try to make a emulator of tube power amplifier, so it can be overdriven when playing in a line or a guitar combo at low volume. Also added speaker simulator and speaker saturation emulator.
As a result, was born the following schematics and the board
With bipolar ± 12V power
Schematics (pdf)
Ready to transfer PCB (pdf)
Upper side assembly (pdf)
Bottom side assembly (pdf)
Assembled board
With single-supply +12 V
Schematics (pdf)
Ready to transfer PCB (pdf)
Upper side assembly (pdf)
Bottom side assembly (pdf)
Some comments to the schematics:
Potentiometer P1 is used to set quiescent current (with no signal) of 2 mA for each output transistor. Potentiometer P2 used to set the desired level of speaker saturation.
To the connector J2 are connected "Presence" and "Depth" controls:
Output signal Limitation
Samples:
Overdriven (minimum saturation)