lc 3 headunit convertor to rca

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=129112
Printed Date: May 05, 2024 at 12:18 PM

Topic: lc 3 headunit convertor to rca

Posted By: ezrollin
Subject: lc 3 headunit convertor to rca
Date Posted: November 06, 2011 at 8:30 AM

Stats:
2x - 275w 2 channel DVC 2/8ohm crossfire 12" subs
(DVC=series,speakers=parallel)
1x - 300w 2 channel 2/8ohm jensen amp
1x - 200w 2 channel 2/4/8ohm crossfire amp
1x - LC-3 headunit convertor to RCA
1x - stock 2007 chevy silverado classic head unit with wires directly to the truck's stock speakers

I ONLY have 1 amp hooked up at a time!

I'm trying to hook up the LC-3 so I can convert my stock headunits speaker output to RCA so I can hook up my amp to my subs. I'm wiring the left LC-3 + and - wires to the headunit's left rear + and - Then right rear to LC-3's right + and - but I'm getting no output from the LC-3! I know its the LC-3 cause I verified with a dvd player's RCAs and the whole system works fine! I've even tried reversing the polarity in the connection from the HU to the LC-3's wires and still no output!
(I was told to do this and was told that all 4 LC-3 wires HAVE to be hooked up)

I've tried changing the HU's balance.
I'm only hooking the amp's remote 12v DC+ input to the 12v DC+ from the car battery to get it to come on(as a temp until I know it will work)

1) How do I get the LC-3 to work?
2) Is it ok to have a 300w 2 chan amp on 2x 275w subs?
(I've done it before with no problems, just keep the gain down)
Thanks!

Replies:

Posted By: ezrollin
Date Posted: November 06, 2011 at 12:46 PM

what the heck is ONE of the HU's speaker output voltage supposed to be? I get like 20.0 mv at the max! (when in use)
thanks

Posted By: i am an idiot
Date Posted: November 06, 2011 at 1:46 PM

Is there a BOSE logo anywhere on the front of the radio, or on the front speaker grills?

Posted By: ezrollin
Date Posted: November 06, 2011 at 2:51 PM

i believe stock head units should put out 2-3v on each speaker?

Posted By: ezrollin
Date Posted: November 06, 2011 at 2:57 PM

oh sorry there is no BOSE anywhere

Posted By: ezrollin
Date Posted: November 06, 2011 at 10:10 PM

I really cant find a pic of the LC-3 and I dont know who makes it but it looks like this:
https://www.amazon.com/Scosche-2-Channel-Adjustable-Lineout-Converter/dp/B00009UHRE/ref=sr_1_1?s=automotive&ie=UTF8&qid=1320638782&sr=1-1

I think its a problem with the HU's output though, it should be 2-3v and I'm only seeing like 20mv

Posted By: ezrollin
Date Posted: November 07, 2011 at 9:54 PM

I couldnt think of anything @ the HU to help.
I think that all the wiring schematics I've found are wrong even though
they really look right.

I came up with a solution, instead, I'm going to tap into the actual speaker area so I KNOW for sure that I've got the right wires.

I bet that will fix my problems and I'll find my 2-3vs!
thanks for all the help!

Posted By: ezrollin
Date Posted: November 19, 2011 at 1:01 AM

That surely did fix my problem, the wiring diagram was just wrong!
Plus it still giving a sup low voltage (like 20mv when it should be 2-3v) but it works now!

I'm wondering, if an amp says its a 2 channel amp @ 300w
and you have 2 subs which say they are 275w.
Whats the best way to set it up? I realize I want the lowest resistance that it will allow so I went for the 2ohm set up.

but if the amp is a 2 channel @ 300w does that mean 150w per channel or does it mean 400w in total when bridged?
thanks!

Posted By: i am an idiot
Date Posted: November 19, 2011 at 5:40 AM

Does the amp say 300 watts x 1 into 4 ohms?

Posted By: ezrollin
Date Posted: November 21, 2011 at 10:02 PM

No it does not specifically say that!

Are you trying to tell me its 300w into 2 channels so really 150w per channel?

Each 12" sub says "275w" so I'm thinking it can handle more?
I've even put more through it and no problems... didnt seem like it had any more power but I never really turned it up!1

Posted By: ezrollin
Date Posted: December 09, 2011 at 8:33 PM

hello? what info do you need to answer my question? thanks

Posted By: i am an idiot
Date Posted: December 10, 2011 at 7:55 AM

Does it have any info such as XXX watts per channel into X Ohms?

Posted By: ezrollin
Date Posted: December 13, 2011 at 9:29 PM

I wish it said something like that
I should probably find a manual or something
but BOTH my crossfire and my jensen amp put it in wording like that

Posted By: ezrollin
Date Posted: December 15, 2011 at 7:10 PM

just says 2-channel bridgeable and dont run mono bridged mode in 2ohms speaker wiring (I assume) configurations

Posted By: ezrollin
Date Posted: December 15, 2011 at 7:25 PM

I think its:

"75x2 rms at 2 ohms stereo, and 150x1 at 4 ohms bridged.
What is the LXA300 RMS output...2 x 75 watts RMS per channel (2 x 100 watts peak) 150 watts RMS bridged into a 4 ohm load"

If both of my subs say 275w, this is per channel right?
So I can add way more watts?

Added watts:     2 speakers x 200/each?   RMS
        or      2 speakers x 100/each?
        or      1 speaker x 50each?

In fact, isnt it a little worse to be under powered than to be overpowered. I'm told you should get an amp that is nearly double the power of the speaker?