Sanity Check on Head Unit Upgrade (1 Viewer)

[dbfw]

For those of you having audio issues while retaining the factory amp, you are using the pre-amp outs on your new head units, correct? I'm not sure why some are having issues and some aren't. Conceptually as far as I understand it, swapping this way keeps everything setup the same as from the factory, just with a more modern head unit. I wonder if some brands of aftermarket head unit are performing differently depending on how they pick up the amp trigger signal, etc. Maybe we should setup a poll on which brand you chose, and whether it worked while retaining the factory amp or not?

I Installed a Pioneer and have had no issues in several years since.

 

[sclay115]

For those of you having audio issues while retaining the factory amp, you are using the pre-amp outs on your new head units, correct? I'm not sure why some are having issues and some aren't. Conceptually as far as I understand it, swapping this way keeps everything setup the same as from the factory, just with a more modern head unit. I wonder if some brands of aftermarket head unit are performing differently depending on how they pick up the amp trigger signal, etc. Maybe we should setup a poll on which brand you chose, and whether it worked while retaining the factory amp or not?

I Installed a Pioneer and have had no issues in several years since.

So, because I thought I knew how to do stereo installs and have had many successes in the past, I never thought about your question.

Here is something that will make me look real stupid, are the preamp outputs specifically defined as the RCA style plugs on the back of the headunit? Or are they the wires that are in the combination plug on the back of the head unit? Or can this vary HU to HU?

*gets ready for onslaught of eye rolling from forum*

 

[dbfw]

So, because I thought I knew how to do stereo installs and have had many successes in the past, I never thought about your question.

Here is something that will make me look real stupid, are the preamp outputs specifically defined as the RCA style plugs on the back of the headunit? Or are they the wires that are in the combination plug on the back of the head unit? Or can this vary HU to HU?

*gets ready for onslaught of eye rolling from forum*

The pre-outs will typically be the RCA style plugs, whereas those in the combination connector are usually to be wired directly to the speakers if using the head unit's integrated amp.

Edit: your head unit's instruction manual should clearly call out which are which, and if it's like my Pioneer, the pre-outs are actually labeled on the unit itself as well. Another thing to pay particular attention to if you're doing this on an LX with Nakamichi vs. a non-Nak LX or a LC is the Nakamichi amp uses a separate ground connection for each of the pre-outs from the head unit, while the other amps share a ground common to all four. This is the main difference in the connector and one that @PabloCruise has explained very well over on his original thread.

 

[War Rig]

Happen to have a link? I'm okay with running wiring from the HU down to the amp to pick up the speaker wiring, but I have to imagine I could bypass it down there, just cannot seem to find a diagram that shows the inbound speaker wiring.

Sure.

Post in thread 'Stereo FAQ' Stereo FAQ - https://forum.ih8mud.com/threads/stereo-faq.50596/post-14945558

 

[suprarx7nut]

For those of you having audio issues while retaining the factory amp, you are using the pre-amp outs on your new head units, correct? I'm not sure why some are having issues and some aren't. Conceptually as far as I understand it, swapping this way keeps everything setup the same as from the factory, just with a more modern head unit. I wonder if some brands of aftermarket head unit are performing differently depending on how they pick up the amp trigger signal, etc. Maybe we should setup a poll on which brand you chose, and whether it worked while retaining the factory amp or not?

I Installed a Pioneer and have had no issues in several years since.

My head unit was pioneer. Yes, using pre-outs.

The issue stems from most (all?) aftermarket units using the stereo frame as ground. The Toyota/Lexus unit does not attempt to use the frame of the stereo as ground. Instead it uses a dedicated audio ground that originates and lives only in the amp and differs from the normal chassis/battery ground.

So, because I thought I knew how to do stereo installs and have had many successes in the past, I never thought about your question.

Here is something that will make me look real stupid, are the preamp outputs specifically defined as the RCA style plugs on the back of the headunit? Or are they the wires that are in the combination plug on the back of the head unit? Or can this vary HU to HU?

*gets ready for onslaught of eye rolling from forum*

Pre outs should always be rca plugs. Potential exceptions being extremely low end units that you'd find on Alibaba or something.

 

[sclay115]

Sure.

Post in thread 'Stereo FAQ' Stereo FAQ - https://forum.ih8mud.com/threads/stereo-faq.50596/post-14945558

Ah okay interesting. Looks like your install was in an LC and that the amp is different than the LX470 Nakamichi setup.

Am I understanding your post correctly when you say that you did not use the RCA outputs on the back of the HU at all and simply bypassed the amp at harnesses under the seat? Effectively having a continuous connection from the shared plug in the back of the HU all the way to the speakers?

 

[War Rig]

Ah okay interesting. Looks like your install was in an LC and that the amp is different than the LX470 Nakamichi setup.

Am I understanding your post correctly when you say that you did not use the RCA outputs on the back of the HU at all and simply bypassed the amp at harnesses under the seat? Effectively having a continuous connection from the shared plug in the back of the HU all the way to the speakers?

That's correct. The HU can easily handle the speakers without an amp, and that allowed me to use the RCAs for the underseat sub.

 

[sclay115]

That's correct. The HU can easily handle the speakers without an amp, and that allowed me to use the RCAs for the underseat sub.

Okay, got it, makes sense. Thanks for your help with this.

Sounds like my weekend task is to figure out the Nakamichi amp in/outs for the speakers.

A forum member graciously sent me the female end of the plug that feeds into the factory stereo dash harness, so that part is sorted. Now just need to figure out the wires at the amp, or just run the 8 speaker wires from the HU harness to the amp and bypass the whole show.

 

[sclay115]

Following up on this, thanks again for everyone's help, was dead simple after everyone's assistance. The resource I used is this:

Help - LX stereo wiring clarification

I have read the threads. Could use some help with the wiring of an aftermarket head unit to the OEM Nakimichi amplifier on a 2000 LX470. This thread seems (to me) to imply I should use pin 1 (White wire, B+) for constant power to the head unit. While this thread seems to imply pulling...

forum.ih8mud.com

It clears up the wiring at the amp under the seat, which is a lot less difficult than it sounds as all of the wire colors match between the connectors in question.

When I was done, I ended up with no connector "B", and almost all of the wires in connector "D" jumped to the wires that used to terminate at connector "B". I ended up de-pinning the wires that I was not using in "D".

An important note is that I left all of the other wires in tact at the amp, and am using the remote turn on signal from the head unit to power on the amp.

Think of it like a bypass but not a bypass. You're sending the speaker signals around the amp, but you're allowing the amp to tell the HU to turn on or whatever voodoo is required to power on the stereo harness in the center stack. This I don't think is the right way to do it, but hey, my stereo works, sounds halfway decent, and I am incredibly glad to be done with hunting for information on this. In the end, it was a simple matchy matchy project.

Cheers everyone!

 

[ChilaMan]

My last LX had a Nak system and I wired my own adapter with no problem. Didn't even need to bypass the amp. It was truly plug and play once I was done pinning.

Theres a great how-to here: Nakamichi Update - '99 LX 470 - https://forum.ih8mud.com/threads/nakamichi-update-99-lx-470.1066006/#post-11738419

I still have an unused connector and pins to build a Nakamichi adapter if you choose to take this route, I'm happy to send them off for cheap. My new LX has a Mark Levinson system which is its own headache.

Hello HStacks. is the LX connector up for sale? I have a 2000 LX470 that I am planning on upgrading HU. Thanks in advance and God Bless!!!!

 

[HStacks]

Hello HStacks. is the LX connector up for sale? I have a 2000 LX470 that I am planning on upgrading HU. Thanks in advance and God Bless!!!!

Unfortunately it’s not. I sent that off to another member shortly after that first post. Sorry!

Check out the other threads mentioned previously. They are pretty easy to make. Just take your time.