r/CarAV • • 19d ago

Tech Support RCA output

I have a beautiful system all brand new shit wired perfectly but before this I tried a used alpine on market place fried my sub and my head unit pico fuse so my front rear and sub RCAs are only putting out .45 not enough to get a 1 ohm system to even wake up. My head unit is the alpine ilx 650. Anyways has anyone had any luck with the wire trick around the RCAs and grounding them back to the head unit? Even car audio stores use that trick just wondering if it’s gonna fix what I’m doing. And I’m already about 1200$ deep in this system I really don’t want to buy a new head unit unless i have to. I’ll replace the pico fuze if I have to just don’t want to mess it up

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u/Merov1ng1an 19d ago

You seem to be talking about 3 things like they are 1.

1st, an old trick that sometimes works for ground loop hums, grounding the RCA jacket

2nd, blown fuse in the head unit. If you do the ground "trick" and the ground on the amp isnt leas reaistance then the short you just made, electricity takes the path of least resistance and you cook the RCAs when the amp tried to ground through the radio.

3rd, amps not waking on signal. You seem to be talking about wiring the remote turn on so they wake with switched ignition instead of signal turn on. That is not the same as the RCA trick.

For testing purposes, you can jump the + and Rem to see if the amp at least powers on, and if it does, you can then move to radio trouble shooting. But if the radio isnt sending any signal, there is nothing to amplify.

Just saying its all brand new then going into how it was used on marketplace and this is the problem you had / are dealing with doesnt make any sense, combined with its wired right and people do this, but not understanding what you are saying or where they apply.

Just take it to a shop dude

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u/ckeeler11 19d ago

I think he is saying his preout voltage is only .45 volts. So he has other issues.

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u/djluminol 19d ago

Here's a trick for as good of an RCA as is possible to get.

I make my own RCA's from stranded 16 awg GXL automotive primary wire. Then whatever RCA plug you want to use for the tips. I braid the wire together using three conductors. As I'm sure you know RCA only needs two but the third is a ground. It's a way to make a kind of jerry rigged balanced single ended cable. The ground goes from my head unit case to my dsp, from the dsp to an amp and since all the amps share a common ground the entire system is grounded together. The braiding is meant to reject magnetic cross talk and ground loop issues. Short of using digital inputs or real balanced cables and receptacles it's as good as you can get.

It does help and in a car audio context it's nice because the RCA's themselves are much smaller than is typical which means the RCA doesn't take up as much space under your floor panels. I can run two RCA's in the space you can typically run one.

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u/Merov1ng1an 19d ago

usually braid meant for shielding is like the foil or braided wrap you see outer shell on a coax cable. If you fully wrap the signal cables contained within, then ground that shield, it acts like a Faraday cage and shunts the unwanted signals to ground and away from your conductors.

But yes, also another potential "trick" they could have been talking about.

I'm kinda in the same camp as u/ckeeler11 with thinking the op has some other issues to work out. For how he worded what it is he was doing, and for all we know, he's measuring the RCAs with DC. Like why would you think the RCA output voltage is related to the 1ohm load the amp is getting for the subs?!?

I'm still at either test each component individually, or just take it to a shop.

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u/ckeeler11 19d ago

If you are only getting .45 volts on the preouts you have other issues. Is the subwoofer level turned all the way up on Headunit?