A few months ago I sold my DMIC-20 to a member of this board but when it arrived it was broken. I finally got around to doing some testing of the unit to see what was wrong. I find out that the chip that converts +5V to +12V for the op amps was fried, probably due to feeding it the wrong polarity! I don't want to make this a big issue but you know who you are, you sure you made that 4-pin correctly? Anywho, I emailed tech support at Graham Patten and Mike Sauter was extremely helpful in answering all of my questions. He is sending me a replacement chip and a shcematic of the DMIC-20 at no charge! If I can't fix it myself he offered to fix it for free as long as I covered shipping! All of this for someone who didn't even buy it new from them. I am thoroughly impressed, it's too bad I have no use for this DMIC and that the ADC-20 doesn't really fit well with my current setup. Thought I would let everyone know to be confident in owning a piece of Graham Patten gear. Huge +T to them.