Ok this might get long and confusing, but stay with me...
I bought the Sony MEX-5DI headunit a while ago, it has no wattage and needs a external amp to power it right. I have a MTX amp that is powering my subs right now at 400 watts x 1, but i can use it 125 x 2. I am going to get a crunch 175 x 4 amp soon, but i want to know if i can get the HU installed, and just plug the mtx one in the headunit using RCA's and have RCA's running to the sub preamp output to the back and have RCA's running to the back for the new amp. So basically like this, RCA's for the front, back, and subs, but only the front hooked up for now to the one amp i have that is 125 x 2. THen when i get my new amp thats 4 channel i can just switch the MTX with the new 4 channel one, power the front speakers and back speakers and the MTX for the subs like im using now. Does that make any sense?

 

If I followed your post right, then yes it will. Just run all your wires and use your MTX for the fronts and when you get another amp, just switch 'em around.

 

the rca's right...i don't need any wires running to the speakers themselves? cuz if its just the RCA's i'll just thell them to plug it all in when i get my headunit installed and do all the connecting myself.

 

You will need to run speaker wire from the 125x2 amp to the HU area to connect to the speakers. If you run all the wires, 3 preamp and 4 speaker pair, it will make it easy to switch the amps when you get the second.

 

alright so your saying that in conjunction to having the RCA going from the headunit to the where the amps are going to be, i need to have speaker wire going to them also?

 

Yes. You need to also run the speaker wires to the amp from either the speakers themselves, or the wiring harness by the deck.

My suggestion is to have all the wiring done at once that you will need when you get your other amp.

 

ok thanx....everything makes sense now....im thinking i should just wait till i get my new amp, but i will go in and talk to the installers to see if i can do it the other way around.