USB Headphone / audio amplifier build

I’ve made a few audio projects recently, two of them actually ended up being in my daily use.

First one is USB sound card / headphone amplifier based on [PCM2906][1], second one is an audio amplifier based on [STA540][2].

Project files are up at my github account, [here][3] and [here][4], respectively. Caveat emptor, I’ve not made sure projects use parts available in public repositories and have relative paths instead of /home/otso/ownCould/git/kicad/etc. STA540-amplifier is outrigth faulty and needs a pull-up resistor from standy to VCC, and grounding input when not actively driven would be a splendid idea also.

My next steps are to combine these projects so that I end up with one device which has automatic mute on speakers when headphone connector is inserted. In process I’ll contribute any footprints to KiCAD so final project will use publicly available parts.

My estimated schedule is something like this:
Q4/2014: Gather team, do system level design, agree on main components (USB-codec, amplifier, opamps, enclosure…)
Q1/2015: Detailed design, schematic, footprint creation, PCB layout, enclosure prototyping, BoM.
Q2/2015: First prototype(s), fixing mistakes and doing improvements
Q3/2015: “Good enough” product to use at home in daily life. Better than the cheapest equivalents on stores.

Estimated budged is ~100 eur / prototype, unit costs will be lower for more pieces.

Learning outcomes are:

  • How to work in a team when designing electronics
  • Using git, KiCAD & LTSpice
  • Analog & digital design
  • Mechanical and thermal design
  • How to order PCBs from industrial manufacturer
  • Soldering, debugging

Anyone interested in this project, please feel free join in at any phase. Absolute beginners and gurus are all welcome.