[sdiy] Tuner and headphone monitor

[Scott Juskiw]

A few months back, Dave Brown offered a couple of chips to build an 
A440 tone generator. I used these as the basis for my latest project: 
a tuner and headphone monitor. I also included a beat frequency 
indicator (I had some panel space to use up). Details can be found 
here:

http://www.tellun.com/motm/diy/tln867/TLN-867.html

Thanks to Dave for making those chips available.