Few Qs about Alpine 3554 amp.

[gmagnan]

I just got an awesome score from a friend of my brother's, who just bought a used car that had an alpine 3554 amp in it. He allready had an amp, subs and the such so I got it off of him for 40$!

The good news: 50W RMS x 4, exactly what I wanted, much cheaper than I expected! The bad news... No speaker level inputs.

From what I understand the stock HU in 3rd Gen Proteges does not have an RCA output on it... So how can one go getting all 4 signals into the amp with as little loss and complications as possible?

Is there some sort of harness or box I can buy to connect my speaker wires to the amp? Can I just splice them onto an RCA cable, I'm guessing positive in the middle and negative between the 2 isolation layers?

 

[JellyBean98]

All you have to do is get a Line level Converter. You tap it onto your speaker wires coming off your deck and it has rca outputs. You will need two converters if you want front and rear fade or get a line level converter that has 4 outputs like the Scosche FAI3. I have used many of these in the past and they are better than the junk you find at autozone. To my surprise you can usually find these at Wal-Mart for $20. We used to carry them at Circuit City and sold them for $40.


Scosche FAI 3

 

[gmagnan]

Do theses converters actually do anything more than tap the postive/negative wires into the inside/outside conductors of the RCA connector though? I've seen Male RCA connectors with shielded pair coming out of the back at radioshack for like 6$ each... For 10$ you can get 15m of 16 guage wire and 4 RCA connectors to make 'em yourself!

What I'm wondering is : Is there something fondamentally different between the RCA output the amp is expecting and the signals the speaker wires carry? Is the voltage off or the phase backwards ect? I know normally for an amplified radio the RCA output carries a pre-amp signal for as not to amplify the distortion the in-board amp causes, but the stock HU only puts out like 5W RMS, I don't think it's amplified.

If anyone is familiar with how amplifiers work, do you know if the signal coming from the speaker level inputs gets converted or powered down or filtered differently than the RCA inputs ?