I'm pretty much done testing PCB v2.0. I'll be submitting v2.0a to the board house today - only difference is an added solder jumper for more control over the EQ filter.
The new power protection stuff seems to be working. It'll take reverse voltage indefinitely without blowing anything up. For forward voltage, somewhere over 50V it let out some of the magic smoke from the PTC fuse and/or the big TVS diode. As soon as the voltage was turned down it started working again, albeit with high current draw until the TVS diode was replaced. The important thing is that this failure mode still leaves it protected. Also, the voltage readout continued working perfectly, which is important because it taps in before the regulator and requires its own protection. I've made some major tweaks to component values in the audio output, so that you can get output close to 1v p-p into a 600 ohm load, even after the filtering that's been added to the output. That's a significant jump from v1.0 and should make it a lot easier to interface with commercial mobiles. The price of the OT2m is going to be going up a bit when the next batch comes in (mostly to cover the added component cost, especially for the demodulator) so order now if you want to get one for the current price. Scott
