Hi everyone,

Trying to get an idea of which route I should go, or if it would even matter for these two options.

I have an amp that has separate inputs for both high level speaker signal as well as low level RCA. The amp is an Alpine MRX-F35

I'm trying to figure out which option I should utilize and was hoping somebody with some experience could lend me some advice on the topic.

Which option would I be better off with.

• Taking the signal from the head unit and bringing it directly to the aftermarket amp via the high level speaker input jack (which would be "easier").

OR

• wire RCA's to the head unit and send the RCA's to the aftermarket amp's RCA input.

Let me know what you guys think.

Thanks!

 

I think I know but I'll ask just in case...is the F35 being used for mids/hi's or a sub amp? If it's for a sub(s), then either will be fine. Taking high level would be simple and work just fine.

If it's for mids/hi's then it's a different ballgame. I still don't know which amps work and which don't with out signal...but I've also heard that it's about getting a strong signal early from the head unit back to your amp (aka....getting a line driver).

Maybe someone else will chime in here b/c I just don't know.

 

The output of the headunit is low level (<1.0v) and not eq'd. The output of the factory amp is high level, eq'd and x'd-over. I'd personally go low level from the output of the deck into your new amp. If you have noise problems try a line driver to increase the low level voltage.

 

Also the less you run the RCAs along power lines the better, especially if not using a line driver. Supposedly twisted and/or better shielded RCAs are better at not picking electrical interference

 

Thanks for the responses!

The amp will be used to push the mids and highs. I know the amp can receive an input voltage as low as .2 ...at least according to its specs. I believe that would qualify it for a straight connection to the HU? Am i on track with that assumption.

Ive only ever done installs on my previous cars with aftermarket HU's. I have zero to little knowledge when comes to factory integrations, LOC's and all that. Sorry for the ignorance on the subject.

Thanks guys

 

As of right now i picked up the signal after the stock amplifier but i have noise issues. From what it looks like i am going to convert my system and do an IB setup. Since i gotta do a lot of things over that will also on my list and im gonna pick up the signal after the head unit. Ive listened closely to the speakers connected to the stock amp and i hear the same noise that is just amplified by the Amplifiers obviously.

Im thinking to run one 12" IDMAX and just power up the front stage. and leave stock speakers as rear fill.

 

Pick up the signal pre-amp. Does your amp accept balanced input? If not pick up a RF-BLD to stick up by the factory amp and send a clean unbalanced signal to your amp. I had noise like Bukvaman that didn't do away until I added a processor that handled balanced signal. Trunkmoney too.

 

I'm not sure if that amp will give you any trouble running pre-amp. The only thing you would lose by trying to run it straight up is time...if you find out it doesn't work (noise). Then you could try a rockford BLD. My works great.

For some reason...I still have some slight noise in my tweeters with gains above (technically lower lol) than about 3v. Not quite sure what my issue is here, but I might try cleaning up the amp(s) grounding spot and the BLD ground spot. It's PLENTY loud enough for me, but that very very slight bit of alt. whine if I set the gains to a true 2v like the MS8 wants...bothers me! Ugh.

 

I think it might be useful to point out that electrical noise is near impossible to eliminate in a car.

TM, have you tried a capacitor? I read that can help clean up dirty power lines.