lm3886 circuit diagram explanation, lm3886 schematic diagram

LM3886 Basics

The LM3886 is a high performance 150W audio power amplifier with mute function. The audio power LM3886 (eg NS) utilizes its own Peak Instantaneous Temperature (°Ke) (SPIKe) protection circuitry to provide an inherently dynamic protection safe operating area (SOA) that outperforms discrete and hybrid amplifiers.

The LM3886T is available in an 11 (staggered) lead non-isolated TO220 package. For testing purposes, a prototype of the amplifier was powered from a regulated ±35V supply. A maximum undistorted output power of about 1 Watt was obtained into 8 Ohms at a drive level of 63Vrms. Dropping the load impedance to 4 Ohms pushed the output power up to no less than 108 Watts. In reality, these power levels can be understood as "musical power", but remember that amplifiers are not usually powered from regulated supplies!

LM3886 amplifier circuit

The circuit requires a well regulated and filtered 28V dual supply.

If you need more punch, extend the supply voltage to 35V.

Switch S1 is used for the mute function, turning it on mutes the amplifier.

LM3886 Circuit Version 1

LM3886 Schematic Version 2

Build the amplifier following the schematic and PCB. As always, when testing it, test it with a broken cheap speaker, it won't be expensive to replace.

If your source is always connected (e.g. a preamplifier is always connected to an amplifier), you can replace C2 by soldering a jumper on the PCB. I strongly recommend doing this if possible to reduce the signal path and improve audio quality. However, if your source may be disconnected (e.g. a CD player), it is recommended that you include C2. If you do not do this, disconnecting the power supply will send a large DC current into the speakers and will most likely damage them. (from)