NOISE on audio system (Rockford 500a2, Sony xec1000, rockford PA2)

[stoke]

hi everyone, let me explain in a easy way what happened with my system. yesterday i took away the Rockford 500a2, Sony xec1000 and rockford PA2 from my car, to find the source of the noise, then i installed on a desk with 2 EV 10'' speakers and power up and the noise was present even playing a song. the installation i made is a laptop connect to the preamp PA2, this to the crossover sony xec1000 and then to the amp.

i started checking each component one by one and when i touched the chassis of the rockford 500a2 amp the noise gets louder and i get an electric shock because i was not wearing my shoes. i disconnect the amp from the crossover and connected directly from the laptop and the noise is no present.

minutes later i keep with no shoes and i change the amp for a rockford 500a4 the noise is present in this amp too and when i touched the chasis of the rockford amp and i get an electric shock and the noise gets louder.

one thing i noted is that when disconnected the rca cables that came from the crossover to the amp, i received an electic shock from the pin of the rca cable terminal.

in some shorts moments the noise dissapeared and the chasis of the amp and the pin of the rca cable terminal did not gives any electric shock

how to find the problem...
i think there is a problem on the power supply of the crossover that leave some current flow to the neg.

[RiLoWa]

I would re-test the system with the Sony out of the signal path to confirm your assumptions. If the hum disappears then you've probably found your problem source.

[Perry Babin]

Was the laptop plugged into an AC outlet?

[stoke]

Originally Posted by Perry Babin

Was the laptop plugged into an AC outlet?

yes

[Perry Babin]

The power supply for the laptop may have been defective allowing voltage to build on the signal lines. Use it with the battery alone to see if that solves the problem.

[stoke]

im not using a power supply for the laptop i had the system outside with an external battery and the laptop connected to my house ac

[Perry Babin]

The power supply is the box between the 120v plug and the laptop connector. Disconnect the laptop from the power supply and allow it to operate off of it's internal battery.