ANR kit.
 

I recently obtained a pair of David Clark H10-20 headsets which have been fitted with an ANR kit. The ANR kit eats 9 volt batteries. Have any readers adapted an ANR kit to run off the aircraft 12 volt system? Did you run it direct or via a voltage reduction adaptor? Thanks.

I have some dc's that have been adapted to use either battery box or plug into aircraft system.

They were done by Richard Holder - you can see it here ANR CONVERSIONS BY ANRMAN

I use lithium 9v batteries, last 8 times longer, rechargeable ones are not reccomended as they dont actually put out a high enough voltage, so the red light is always on, and only last about an hour.
There is a david clark panel power kit available, gives the impression that anr's are not that fussy about precise voltage, worth looking into.