AMP gauge running high charge??

I was hoping someone here could steer me in the right direction. My amp gauge just started running high. I noticed it when my dash lights got brighter. When I drop the the engine RPM the gauge drops, rev up gauge goes up. What should I check first. Any help would be appreciated.

Thanks

Have the battery checked.

Ok, I'll try another battery, I just check the voltage with my multimeter, 17v at high idle. could it be the voltage regulator or would it be the alternator?

Regulator is bad !

Double check your alternator and regulator wire connections. Also make sure the regulator is securely grounded..

Just my $0.03...

very likely the reg itself. way less likely would be alt/brushes & unplug the green field wire at the alt (later type 2 field wire system) & if it stops charging then it ain't the alt/brushes. If it's an early "box" reg it could have lost it's ground continuity but fairly rare. unplug the reg triangle connector till you get it taken care of as that full fielding (17+ volts) will cause multiple problems quickly

What year? Single or dual field connectors?

I switched regulators, steady at 14.7v.
Thanks for all the help guys.