What "amps" do you mean? Is it an aftermarket radio with amplifiers?

Try these suggestions, one step at a time to identify the drain:
-Pull the "main" fuse in the amp wire. It should be located close to the battery. Should be an inline fuse if it's an aftermarket amp.
-Check the amps for a blade-style fuse and pull each one separately (if more than one amp) to see which amp is causing the problem
-Pull the radio and remove the two fuses (one for constant power, one for ignition power) and see what happens.

You have something killing your battery, and it sounds related to the radio. Disconnect all of the radio stuff until the drain goes away, then start adding back one thing at a time until you find the problem. No need to use your meter as you've narrowed it down quite a bit.

Easiest way is to just stop the drain, and then slowly (wait a few days each time) add one thing back till you find the offender!

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