The HPM-1 module is a high quality headphone amplifier module originally designed to be part of the stereo line mixer project. It features a volume control and 1/4" headphone jack and is powered with a bipolar (+/-16V) power supply.

The module measures just 66mm x 81mm and could be housed in a variety of ways for use in other projects. The headphones are driven using the well-known JRC NJM4556A devices. One pair of op-amps is wired to drive each channel. The input is buffered using a NE5532 op-amp.

HPM-1 Circuit (pdf) HPM-1 BOM (pdf) NJM4556A data sheet (pdf)
HPM-1 PCB (pdf)   NE5532 data sheet (pdf)


HPM-1 module











HPM-1 Module