I have made a mod to the cable I use.
Everytime I forgot to plug out, so the active bass is not so active anymore at any moment I cant buy a 9V block.
The instrument plug is changed from mono to stereo (TRS) I have used a Neutrik so I could combine it with a little switch on a short lead. Connected on the sleeve and ring. The bass doesnt see the plug in the Off-position and switched on, its like a mono plug and works as required. In an active bass there is a stereoconnector which switches the preamp or pickups on as the ring and sleeve are connected by the monoplug. The switch simulates a monoplug in the on-position, in the off-position there is nothing connected and the preamp stays off and uses no capacity from the battery.
Right now its simply pushing the switch off when I place my Ibanez SR in a stand. Way easier then pulling the plug from the recessed outputconnector. Costs me less than 10 bucks