I'm trying to implement volume control using a digital potentiometer (LM386) and audio amplifier (MCP4131). The way I have it setup, I'm outputting square wave audio signals out of a PWM pin on the Particle P1 board.
The amplitude of the square wave is adjusted using a digital potentiometer (acts as a moving voltage divider) before it enters a LM386 audio amplifier.
Where I'm having trouble is, when the amplitude of the square wave is adjusted below 2V (feeding this into pin 3), the LM386 audio amplifier stops outputting a signal (pin 5). Everything works fine above 2V and I get a good amplified square wave out of pin 5. This is a problem because it limits the desired range of volume control. I'd like to get softer audio as well.
I've read the LM386 datasheet back and forth and can't see to find a specification that would explain this. I think I may be missing something pretty basic… The schematic is attached.
Any help would be appreciated. If there are any questions about the set-up, let me know!