I have Pioneer 740MP.
My another amp is a diamond audio D3.400 -->works great, still trying to tune it but always getting better.
I have a battery terminal with a 4ga and 0ga. The 4 ga is going to the D3.400 and 0ga to the D2. Both amps come on. I have noticed that in wiring if I use the left side, the remote knob works, but the right side it does not.
My friend said it did not have a cross-over, but there are a couple of tuning options. I assume that would be the cross-over.
What I belive is occuring is that I have one tuning option cancelling out the other tuning option. I have moved the gain up and down with no real results, however I do have dimming which leads me to belive the amp is requiring more power at higher gains (which makes sense to me) however output is not increased.
I am running 2 pioneer 2000spls wired down to 1 ohm.
I can provide any more info if needed.