For those builders looking for cheap 400Hz power supply I found you a solution. I am using the one linked below and am working with them to build and make available the 6amp version. I am driving my ADI, HSI, AP and Flaps gauge with the smaller 1.7A Unit found here, This thing is QUIET, perfect 400Hz sine wave, no ripple, and very small, about size of 2 packs of cigs

If you get one please let me know.

Thanks and spread the word.