Lights flickering slightly?

I tested my alternator yesterday, and it is working fine. It must be the brand new voltage regulator, I hate when that happens! $50 for the 'good one' and I'm chasing the problem back to a new part. No chance of returning electrical parts either.
I had the oem looking one that mopar performance makes and it fried the first time it was powered up...went to auto parts and picked up a silver one and it runs fine....I also had an alternator blow up and throw white ceramic pieces all over the engine compartment...