I have done many stereo systems, but never dealt with my SC400's Nak system before.

My amp blew, if I replace it with a 5ch amp... wire it all nice... What are the pro's I will generally see? Im assuming a nice warmer, richer sound... Will it be able to be played louder? My stock Nak system isnt very loud (windows down is eh...) Have you guys seen a nice boost in volume and overall richness of sound?

Will I still be able to controll high mid lows through the Nak headunit?

Next on my list is to replace speakers as well...

 

I'm not sure about the Nak system but the OEM Pioneer amp and OEM speakers in my GS430 were all 5 Ohm.

IMHO I would reaplce the entire soundsystem.

 

They are 4 ohm speakers all around, so there will be no complications.

I would love to replace everything, but its not in my budget to do so. I have other stuff to worry about (5sp swap).

 

Yeah!!! Now I get to tell about my less noticeable mods.... As you've seen everything except the two front tweeters have been replaced in my car. Basically a five channel would work fine, thats what I originally considered. The sub would need to be replaced, its an odd 5 Ohm 10". And the speakers should be fine until your ready to replace all of them unless they've rotted out. So simply (sort of) find a 5 channel and just tackle the ***** of rewiring. Honestly too, your looking for more of a different route in your car so I would maybe just replace the factory speakers and go with a used or rebuilt amp. That way the other priorities can be taken care of because this stuff is expensive as %#!@. I have well over $2000 dollars in my setup. I'm an audiophile so thats the route I took first, now its time for speed :-)

Oh and a new amp will definitely be louder and cleaner. Just replace the stock speakers and your then you're really talkin.

 

Aftermarket with the stock speakers will work for a short time until the stockers bite the bullet, which they will with additional power.

Upgrade the speakers at the same time as the amp and you will be very pleased.

I am currently running MB Quart Components (5.25" mid and 1" tweet in each door, and 5.25" coaxials in the rear deck) and a JL Audio IB4 10" sub in the factory location (custom baffle made to clear the gas tank). Everything is run through a HiFonics Zeus 5ch amp (35w ea for the components and 200w to the sub). Still using the factory Head unit and 12 disc changer.

Crystal clear sound and 128.7 dB on the SPL meter.

 

I have a 94' ls400 with the nak system and amp. How would i go about replacing the factory amp with an aftermarket amp?

Do you guys have a wiring diagram?

 

You'll need to probe the harness in the trunk to determine which wires are the to which speaker, and which is the remote turn-on (remember not to confuse this with the power antenna wire. The remote will stay on when the radio is switched to CD while the antenna goes from power to ground when the radio is switched to CD).

Toyota uses a floating ground schematic but luckily the signal is already RCA level so RCA's can be "spliced" in. Be CAREFUL when stripping the RCA's as the ground wire is inside the first layer of shielding but outside the actual signal line shielding. Once you determine what wire in the the harness is the floating ground you will combine all the grounds from the RCA's and solder them to this wire.

 

This was what i was hoping to be able to do. Find all of the harness that is going from the output of the headunit to the trunk. using those harness to figure out which ones are speaker output that would plug into the input of the factory amp. Once finding that i would figure out which wire is which speaker and just plug it into a LOC. From the LOC Plug in my amp through rca output.

I will then find the harness that original went into the output of the factory amp because that would indicate that those are the speaker wires that went to the speaker and just plug it into my aftermarket amp.

Does that make any sense? Or is it much harder to do then that?