If you only have one set of pre-amp outouts you can run it back to the amps and daisy chain them. Run input to one amp and output on that amp to the next.
Not all amps have RCA outputs. Another option is to use Y-adapters to split the signal. You don't lose much strength in the signal as devices wired in parallel have the same voltage across them.
An electronic crossover works well too. They have 1-3 inputs and at least as many outputs usually 2-3. This allows you to select which frequencies get to each amplifier.
Sounds like a component inside the EQ is blown. If you still have warranty take it back. If not, oh well, they are cheap anyway. I can get 10 band eq's for about $30