I was wondering the same thing. I love my ACE 250, but was thinking about getting the bigger coil.
I have another questions that is kind of unrelated (and probably stupid), but here it goes:
Does the Detector still give an accurate depth prediction when using the bigger (or smaller) coils?
I think that the ACE gives you a fairly accurate depth reading with the standard coil and was wondering if you had to compensate or something with the 9X12 coil.
the depth is still pretty spot on.
havent had any interferance.
pinpointing can be very hard in a even soso trashy area.since the ace turns to all-metal in pinpoint mode it does pick up eveything.
i just use the stock coil until ive cleared most trash,then switch to the 9/12 for better depth.
On My GTI 2500 using the bigger coil, depth accuracy is good. It helps to give a better indication of those marginal
targets. On a circular coil depth is about the coil circumference. 12" coil= up to 12" depths.
Anyway thats what Ive read- don't know the effect of the elliptical coils.
HH