Between work and home obligations, things have been a little tight for project work. So this morning I soldered up some headphone jacks that I had, did simple continuity tests on them, wired them into a protoboard, and gave them a whirl.

They're not the best jacks - there was some left bleed and right bleed (but that could have been the audio test that I was trying - I'll use audacity later to come up with definitive test sounds).

They worked! Okay - so later today, more testing, then some measurements, some resistors, and a check on the music output with my sound pattern.