LM12 audio amplifier circuit diagram
This LM12 audio amplifier circuit will provide a high output power on a 8 ohms or 4 ohms load impedance. The maximum output power delivered by this LM12 audio amplifier circuit is around 60 watts on a 4 ohms load and 100 watts on a 4 ohms load on each channel .
This LM12 high power audio amplifier is composed on two principals stages :
A preamplifier stage based on the LM381N dual preamplifier integrated circuit and a power amplifier stage based on the LM12 high power operational amplifier .
To obtain the full power from this audio amplifier you will need to use a dual 35 volts power supply circuit .
The input sensitivity of the audio preamplifier must be set to about 300 mv by R1, R2 variable resistors .
To obtain more audio power from this audio amplifier you can use it in the bridge mode configuration , but in that way you will obtain a mono power amplifier circuit .
If you want to use it in bridge configuration or stereo configuration just design the pcb board in the stereo mode configuration and modify the jumpers in this way :
Install jumpers JU2 and JU 4
Remove R13 with jumper
Replace R14 with a 113 k resistor ( 1 % )
Replace R15 with a 4.5 k resistor ( 1 % )
Cut foil between pads from R14 and ground
Connect the input signal to the left input
Connect the output between Right and Left output