An LM386 fixed-gain guitar headphone amp.
Yet another LM386-based audio amplifier similar to the LittleGem/A386/Smokey series, this time adapted as a guitar headphone amp.
There are various "headphone amp" circuits based on the LM386. After trying many of the variations, I found that going back to basics performed just about the best (per the reference circuits in the datasheet).
Features of the circuit:
- default 20x gain (no extra components required)
- simple capacitive-coupling with ~50k impedence matching for a guitar input
- ring of the 6.35mm connector is used to switch power - use with a standard mono cable
- mono output is sent to left and right channels of the headphone socket
How it performs:
- clean signal with a slight warm overdrive at maximum guitar ouput
- performance can be a bit temperamental on a broadboard, but when I put it on a protoboard it performs quite well.
- LM386 datasheet
- Based on "Project 07 - Guitar Headphone Amplifier" from Beginning Analog Electronics through Projects
- my LittleGem/A386 build
- MXR™ Headphone Amp - circuit details of an alternative unit