Brief Description: Bose A20 Headset - Auto On Modification
I bought a couple pairs of the new Bose A20's for the RV-8 and they are very nice. NR is better than the Bose X's and they seem to fit my head a little better too.
But I quickly discovered that with the A20's you now have to hit the NR Power button *every time* you start the aircraft even if you have them panel powered. The older Bose X headsets have a slide switch for the NR power and so you can just put the slide switch in the On position and not worry about it.
I really didn't like having to turn the NR on all the time and having to remind my passengers about it, so I came up with a modification that will automatically turn the NR on when panel power is applied. Its pretty simple, but requires some special tools. Its completely self-contained inside the Control Module and works great. The modification is generally only for installations that are panel-powered, but you could do the modification to a unit that is normally battery powered with no adverse effect. With the modification, the NR Power button will work normally in battery power installations. Even in panel power installations, the NR Power button can still be used to power the NR off and then on again.
I have created web page on the procedure including step-by-step photos and instructions: