what kind of relays do i need?

i have a 96 chevy beretta and i am putting in a second head unit for undisclosed reasons.i want to be able to flip one (toggle) switch to switch between active head units. my car has 12 wires coming from harness. one of them is a constant 12v for memory so i dont need a relay for that i just run it to both the head units(to keep all the settings for both). so now we are down to 11 wires. but i have an amp so i have 5 wires there (remote, and the rca(pos,neg and another pos, neg)) the remote wire i can just connect strait to the 12 acc from the original harness so it turns my amp on when my car turns on, no matter what head unit it active.so thats just 4 wires from my amp, add that to my original 11 and we got 15 wires total. now the part that i need help with. i have no idea what type on relays i need or anything. i know i need a relay that has connections in both the on-off positions so head unit A will be active in the normally off position, while head unit B will be active in the on position. so i know i will need more than one relay because i doubt they make a readily available 16 terminal relay with 32 on- off terminals(guessing 16 because it would be weird if they made odd numbered relays) the relays need to handle amplified signals since each unit has a pre-amp. also gold platted would be nice (at least for the rca's relays)and please correct me if any of my theory is wrong. Thank you for your time, kyle

3 4 pole changeovers should cover this. Used to do this aftermarket for people who wanted an 8 track to go with the factory radiocassette-40 years ago! You won't need a switch, the remote amp to trigger the relays The amp leads can all be commoned (2 out of 1 connectors) If you do want a switch, you'll need a latching 1pco type

howie ll wrote: 3 4 pole changeovers should cover this. Used to do this aftermarket for people who wanted an 8 track to go with the factory radiocassette-40 years ago! You won't need a switch, the remote amp to trigger the relays The amp leads can all be commoned (2 out of 1 connectors) If you do want a switch, you'll need a latching 1pco type

wow, thanks for the fast reply. i dont quite understand the switch part though. how would i switch between the head units? and what is a latching 1pco type?

If you need to ask those questions you can't do it

sorry? i'm 17 and in two college electronics classes, i'm not an expert,i'm an amateur. this is the reason i came to the forums, was to ask for help/assistance in this little project and the knowledge i would gain would also be a plus. well thanks for your help anyways:)

Howie, your first reply is not the easiest to understand.  Maybe is has to do with being on a different side of the pond.  Regardless, your second reply is of no help at all. the12volt • Support the12volt.com

electronics1994, if you do not want to use use relays, there are switching units available. In your case you'd need one for speaker level switching and one for source switching.

If you choose to use relays, you do not need to switch power between the head units. You just need to switch the output signals between the two head units to your speakers and amplifer. If your current setup has four speakers plus an amplifer for subs, you could use 11 SPDT relays. 2 for each speaker, one for each amplifer input signal and one for your remote turn on lead to adequately power the other 10 relays.  If I get a chance this evening, I'll draw a digram for you.

the12volt • Support the12volt.com

yes i was thinking about leaving power to both, but i was afraid that my small battery/alternator couldnt keep up with two head units and an amp on top of that. but anyhow, what would be the pros and cons between my relay method and your method? as of preformance, cost, and quality of output? sorry for all the questions i know you have more important things to do, but i just dont want to do/ buy all this and it doesnt work, or it sounds terrible or god forbid, catch on fire haha thank you so much for your help, kyle

Do either of the radios have an aux input? 

i am an idiot wrote: Do either of the radios have an aux input?

both have 3.5mm in the front, one has rca aux in also. why? haha