Okay, I have searched and couldn’t find anything on this.

Situation: Wiring aftermarket head unit into sc300 with stock amp/speakers/sub.
Okay, so to make all speakers work and subwoofer, I have to wire the remote on to the amp (got the wiring diagram from intelluxual) and use line level converters to go to head unit.

My question is, does the head unit have to have 3 pre outs? Or can I wire the LR, LF, RR, RF wires on the head unit to the stock amp, and just use 1 pre out/level converter for the sub? I’m a bit confused. I do not want to change the amp or not have the sub working I just need to know if what I'm picturing will work:

 

I'm not familiar with that particular factory amp, but I will try to provide some general help.

1. How many sets of inputs does the factory amp have?
2. Did your OEM radio have sub controls built in?

If it only has front & rear inputs (4 channel - stereo) then you should be ok. This means that all the signal processing for the subwoofer is done within the amplifier or downstream of the amplifier via some sort of crossover network.

2. If the factory amp actually had an independent subwoofer input, then it would get a little tricky and you would either need to have a subwoofer out from your new headunit or you would have to create a non-fading sub out by using another line out converter.

Hope this helps...

 

The nakamichi amp powers 4 speakers, and 2 tweeters, and a 10inch sub. There is a seperate plug on the amp that goes to the sub. So for this i would need a line level converter for the sub wires, and connect an rca to the headunits sub out?

 

First, the signals leave the head unit and go to the amp.

Then, the signals leave the amp and go to the speakers.

Easiest (and IMO best) way is to run the stock speakers off the head unit's built in amplifier and buy a small mono or two channel bridgable amplifier for the sub. Use the line level outs from the regular speakers. Use the sub pre-outs for the amp for the sub.

 

Absolutely.

 

I must have posted this at least a dozen times. Go to my website and select NakHack.

Peace.

http://www.technicalhelp4u.com/lexus/

If you still have ?'s pm me.

 

I do not want to spend any money on another amp. I also do not want to run the speakers from the headunit, because i ran stock speakers on my old bmw with a alpine 9827, and the headunit lighting would dim.

So heres my plan, i just want to know if it would work. Run remote on from head unit to the stock amp. Add a line level converter to sub wires, run the rca cable to headunit. splice stock speaker wires that go to amp, and connect them to headunit speaker wires. If this will not work, i guess i have no choice but to buy a mono amp for the woofer and maybe speakers.

TIA

 

I guess some of my old posts on this subject did not come up during your search. Not sure if you have the Pio or Nak but the only diff is a seperate sub amp for the Pio. Both amps have a line level input from the stock HU.

1. No problem running the stock speakers with your new HU. Your lights wont dim. If they do, then search for 'electrical ghosts' as the problem is not with the stereo mods.

2. Another amp is not needed, unless you want to bypass the stock amps - in which case you don't even need the schematics on my site.

3. Yes, use remote to turn on stock amp. Wire is identified in my schematics.

4. You dont need a converter for your sub wires. Check the schematic - it is a line level input. Your new HU does have line level outputs right?

P

 

Okay from what I'm understanding, i don't have to run any rca's for the sub? I just have to have the amp powered on, and the sub will work, i just need to get sound signal to the amp from head unit correct?

So the use of rca's is not necessary, i can just splice from the stock head unit harness that goes to the back?

 

If you're using the stock speakers and the stock amp, why are you even bothering to upgrade your headunit?

 

Why? Because the cd changer is busted, and the only other option is to get a walkman cd player and use the tape player. So, $130 for a headunit that plays mp3's and has a usb slot for a thumb drive is good enough for me. I do not plan on keeping the car for long to go all out on a audio system.

 

This should be the Pioneer CD wiring diagram.

 

So what if the headunit lighting dims. What speakers were in your BMW? What power rating? How many speakers total? I'm running my regular stock speakers off my new head unit and removed the old amp, head unit, and CD changer. There is no head unit dimming involved. But I'm also using a seperate amp for different subs.