alternator problems

i am getting ready to change this thing again,94 formula LT1 5.7L,problem is it will charge when u first start the car until it warms up then it will slowly go down to 11amps and stay,will stay at 11 even in drive.it does have a slight bearing noise from the alternator.could the belt be to tight causing my problem?alignment is straight so i know its not that.

youve replced the alt recently? do the lights dim after warming up or any noticeable electrical loss or are you just seeing amps on the gauge go down?