I got an older Whites PI 3000 with a 6 AA Battery pack. Is there any problem with me just using a regular 9 volt battery instead? One AA= 1.5 volts x 6= 9 volts, correct?
The only potential problem is that the 9V battery has significantly higher internal resistance than the 6-pack. In a VLF detector that usually doesn't matter, but in a PI it can limit coil current and decrease depth. It won't hurt to try, and do some depth tests.