headunit take too much power

Hey, i just removed my amplifier that i used with my speakers (4).. So i hook them to my Headunit ( Sony XPLOD CDX GT220 ).. My subwoofer are 2 RF P1 powered by a Pioneer GM-D7400M ( Fuse 50A ) mono amplifier.. I upgraded the big 3 in my car ( Chevy cavalier ).. So here the deal ... Now my light are dimming badly than before and my subwoofer cut at high volume ( Voltage drop ).. Before when i doesnt have my speakers pluged on my HU all was working fine.. What is happening?

Well if the only thing you changed was wiring up the speakers to the headunit...Dis-connect whatever you wired up to the HU and leave the subs connected...Then turn up the volume and see if you experience the same problem...!M.E.C.P & First-Class

Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!

What is the voltage dropping to...? What did you do with the wires connected to the amp you dis-connected...? Is the power wire fused...?M.E.C.P & First-Class

Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!

Well voltage drop around 10 volts.. I removed the old wire (Before it was one gauge 4 to two gauge 4 now is just one single 4 gauge.. Ground is the same.. power wire fused at 80A...

your voltage should not even drop below 12 volts with an amp that smallCustom Enclosure Design

I know.. i think i will replace the ground wire battery to chassi because i think its damaged..

did you upgrade the BIG THREE at the time you removed the amp?

No .. i upgraded the big three when i installed my first amp.. the pioneer