At what point do I need to use an LOC

[n2audio 5,000+ posts]

I'm planning an install using my stock HU.

It is a dodge/chrysler with the infinity system.

In this system there are 4 small amps - one attached to each of four 6x9's.

There is a small awg (18-22) (+/-) lead from the HU to each amp.

I was HOPING I could tap directly into these wires and use that for amp input (no LOC)

However, I have discovered those small wires are not ACTUALLY line level.

In vehicles w/o the infinity system the HU powers the speakers directly w/o the additional amps at the speakers.

I'm pretty sure the infinity amps produce around 20w -- so I would expect the non-infinity system being powered directly by the HU would be 10w or so?? If anyone knows for sure that would be very helpful.

Getting to my question -- if this 10w guesstimation is in the ballpark that's like 6.3v (at 4 ohms). My amp's rca inputs are good for 7 and 8v respectively. Am I safe to use this "high level" signal as a feed for my amp's "low level" rca inputs?

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[mylows10 5,000+ posts]

Yes

 

[CrossoverOre 10+ year member]

no. you will need to use an loc. the rca inputs are not isolated grounds. You will have problems when going straight from the factory amp output wires to the rca inputs on the aftermarket amp.

 

[fasfocus00 5,000+ posts]

what amp are you using. some amp allow you, mainly newer mainstream brands.

 

[n2audio 5,000+ posts]

what amp are you using. some amp allow you, mainly newer mainstream brands.

One's old, one's older -- sig.

My 4 ch is probably an '02-05 model or so. My sub amp is ~'00-'01.

The 4x400d has a high/low switch. If one of them is capable I figure it would be the one.

But it sounds like the LOC's going to have to happen.