Is the sub amp the same as the mids/tweeter amp in the mach 460 system.

There aren't any "subs" in the 460 system.

Your front channels amplifier is located under the radio/tape deck or cd pocket whichever you have, in front of your shifter bezel.

Your rear channel is powered by the amplifiers in the rear deck enclosure.

Thanks, sorry not "sub" amp.For clarification,is the rear channel amp different than the front channels amp?

There is two in the back for the back two speakers.