98' LX470 After Market Head Unit (Stereo) Replacement

[ghong14]

Hello fellow Forum Members. Wanted to get everyone's expertise on a current pet project I am thinking of doing for my LX 470 HU. The head unit is OEM and is not functioning properly and I am thinking of switching it out with a Pioneer NEX 4200 System. I wanted to get some thoughts on the following things I am looking at:

1. There is a lot of talk about Mark Levinson and Nakamichi stereos, but my HU simply says "Lexus Premium Sound System." Does this mean that my stereo unit is neither of the brand?

2. I am looking to replace the HU with the an Pioneer AVH NEX 4200:
AVH-4200NEX - 2-DIN Flagship Multimedia DVD Receiver with 7" WVGA Touchscreen Display

3. Love to get some guidance on bracketing. Beatsonics seems to sell the bracketing for an aftermarket HU for $120, but I found an ebay seller selling the unit for $49. But love to hear from you guys on whether the brackets are the same:

Beat-Sonic SLA-100fb

LEXUS LX470 1998-2002 Radio Installation Dash Kit Standard 2DIN SATIN BLACK | eBay

4. I would like to keep the factory speakers and AMP. Is the wiring going to complicate anything here?

5. There is alot of talk about the AMP 12V Trigger based on this forum. Is this still needed?

Aftermarket Stereo in 98 LX470 But Keeping Factory Speakers (& Amp, If Applicable)

I appreciate everyone's help! Thanks!

 

[suprarx7nut]

Watch out for the grounding method used in the factory amp. The 98-99 Land cruiser has isolated grounds in the head unit and amp and that makes it completely incompatible with aftermarket head units where they always use the hu chassis as a part of the ground circuit.

I suspect the 98-99 Lexus is similar.

Be prepared to bypass or replace the amp.

 

[Jonathan Case]

Hi ghong14 - I did this same project with my 98 LX470 this year, and concur with the above. If you're looking to keep this affordable, you'll want to bypass the amp and just use the head unit to power speakers. I had my new HU installed and the amp bypassed by a professional after many hours of trying to get it to work myself (in spite of following several tutorials on here, I had no luck even getting the new HU to power on, so I gave up and took it in). The amp in ours is a Pioneer. You do lose the subwoofer functionality by bypassing the amp (though I notice little difference in sound quality, personally). If you want to retain the sub, you'll need to get a new amp. Annoying, I know.

As far as the brackets, I went with the Beatsonic kit at the time, but that one on eBay looks pretty identical. The plastic part and brackets are nothing fancy, but it looks just fine installed - I can't imagine you'd lose much going with the cheaper option.

Seek out the other forum posts on this install for more info - There's 2 or 3 pretty detailed ones for similar vehicles/sound systems.

 

[ghong14]

Hi ghong14 - I did this same project with my 98 LX470 this year, and concur with the above. If you're looking to keep this affordable, you'll want to bypass the amp and just use the head unit to power speakers. I had my new HU installed and the amp bypassed by a professional after many hours of trying to get it to work myself (in spite of following several tutorials on here, I had no luck even getting the new HU to power on, so I gave up and took it in). The amp in ours is a Pioneer. You do lose the subwoofer functionality by bypassing the amp (though I notice little difference in sound quality, personally). If you want to retain the sub, you'll need to get a new amp. Annoying, I know.

As far as the brackets, I went with the Beatsonic kit at the time, but that one on eBay looks pretty identical. The plastic part and brackets are nothing fancy, but it looks just fine installed - I can't imagine you'd lose much going with the cheaper option.

Seek out the other forum posts on this install for more info - There's 2 or 3 pretty detailed ones for similar vehicles/sound systems.

Thanks Jonathan this helps alot. Can you elaborae on a little more why the AMP needs to be bypassed?

 

[ghong14]

Watch out for the grounding method used in the factory amp. The 98-99 Land cruiser has isolated grounds in the head unit and amp and that makes it completely incompatible with aftermarket head units where they always use the hu chassis as a part of the ground circuit.

I suspect the 98-99 Lexus is similar.

Be prepared to bypass or replace the amp.

ThanksSupra but why does the AMP need to be bypassed?

 

[KiPod]

I hard wired a Bluetooth system into my 99 LX using the factory amp. I believe it was pin 14 on the radio harness (black/red) that needs to send a +12v signal for the amp to turn on. I wired that to a 12v accessory signal so every time the car turns on the amp turns on. I wired in female RCA connections into the radio harness and used the normal power and ground for my Bluetooth device and USB charger. Right page with connectors is how it was. Left page was what I used. It might be a little different but I was able to keep the amp. All I have visible is an iOmount for the phone/tablet/monitor and a volume knob. Hope this helps a little with options.

 

[ghong14]

View attachment 1531007 View attachment 1531008 View attachment 1531004 View attachment 1531005 View attachment 1531006 I hard wired a Bluetooth system into my 99 LX using the factory amp. I believe it was pin 14 on the radio harness (black/red) that needs to send a +12v signal for the amp to turn on. I wired that to a 12v accessory signal so every time the car turns on the amp turns on. I wired in female RCA connections into the radio harness and used the normal power and ground for my Bluetooth device and USB charger. Right page with connectors is how it was. Left page was what I used. It might be a little different but I was able to keep the amp. All I have visible is an iOmount for the phone/tablet/monitor and a volume knob. Hope this helps a little with options.

Thanks! This book looks really interesting. Any other pointers for this setup? I am not sure why some of the other members here are having an issue and having to bypass the amp. Any thoughts on that? Thank!

 

[suprarx7nut]

In the Land Cruiser from 98-99, the factory amp and head unit have an isolated ground (Let's call it OAG - OEM Amp Ground). It does NOT act like chassis ground. It is a unique ground used only for the stereo. This ground (OAG) is used for the speaker lines in the factory wiring.

On aftermarket head units it is a completely universal practice for the manufacturer to use the outer casing of the head unit for ground. They will also have a ground wire in the harness. They count on this ground feed to be chassis ground and they count on it being the only ground in the equation.

When you plug in an aftermarket head unit to the LC the new head unit will use chassis ground for its speaker lines, both high and low level. Now you will have chassis ground connected to the factory amp, which is meant to work ONLY with OAG. When you mix the two you will now hear any variance in the two grounds through the speakers as a hiss and whine. Remember, OAG and chassis ground are not the same thing. You want one common ground on the speaker lines. This is NOT POSSIBLE with the 98-99 LC factory amp and an aftermarket head unit without extensive wiring and mounting modification.

Some 100 series seem to not be affected by this, but any system that uses a unique ground in the factory amp setup WILL have issues. You can mask it with inline filters, but they will always diminish the sound quality.

Anytime you're diving into a 100 Series stereo replacement I'd just count on bypassing. See my video below for how I did it. Completely bypassed for very little investment and it's completely reversible if I ever wanted to put the factory stuff back in.

 

[ghong14]

In the Land Cruiser from 98-99, the factory amp and head unit have an isolated ground (Let's call it OAG - OEM Amp Ground). It does NOT act like chassis ground. It is a unique ground used only for the stereo. This ground (OAG) is used for the speaker lines in the factory wiring.

On aftermarket head units it is a completely universal practice for the manufacturer to use the outer casing of the head unit for ground. They will also have a ground wire in the harness. They count on this ground feed to be chassis ground and they count on it being the only ground in the equation.

When you plug in an aftermarket head unit to the LC the new head unit will use chassis ground for its speaker lines, both high and low level. Now you will have chassis ground connected to the factory amp, which is meant to work ONLY with OAG. When you mix the two you will now hear any variance in the two grounds through the speakers as a hiss and whine. Remember, OAG and chassis ground are not the same thing. You want one common ground on the speaker lines. This is NOT POSSIBLE with the 98-99 LC factory amp and an aftermarket head unit without extensive wiring and mounting modification.

Some 100 series seem to not be affected by this, but any system that uses a unique ground in the factory amp setup WILL have issues. You can mask it with inline filters, but they will always diminish the sound quality.

Anytime you're diving into a 100 Series stereo replacement I'd just count on bypassing. See my video below for how I did it. Completely bypassed for very little investment and it's completely reversible if I ever wanted to put the factory stuff back in.

This makes a lot of sense but just wondering how KiPod was able to get away with his AMP install with the HU? I just wanted to make the setup as easy as possible. Any thoughts?

 

[PabloCruise]

View attachment 1531007 View attachment 1531008 View attachment 1531004 View attachment 1531005 View attachment 1531006 I hard wired a Bluetooth system into my 99 LX using the factory amp. I believe it was pin 14 on the radio harness (black/red) that needs to send a +12v signal for the amp to turn on. I wired that to a 12v accessory signal so every time the car turns on the amp turns on. I wired in female RCA connections into the radio harness and used the normal power and ground for my Bluetooth device and USB charger. Right page with connectors is how it was. Left page was what I used. It might be a little different but I was able to keep the amp. All I have visible is an iOmount for the phone/tablet/monitor and a volume knob. Hope this helps a little with options.

Looks like some useful information for me - also w/ a '99 LX - thanks!

 

[KiPod]

I heard that the factory amp wouldn't work with aftermarket either because the radio and amp each sent a signal to each other and if one was removed the other wouldn't power up. I tend to buy wiring diagram books for my vehicles because I tend to mess with stuff and with projects like this hey come in handy. I'm not sure why mine works but others don't. I just hard wired a USB outlet and the amp signal wire to the switched +12v. Then I used a apple 30pin harness that has USB and RCA. The USB plugged into the outlet, the RCA's plugged into a volume control and then into the RCA's I hard wired into the factory radio harness. Hope this makes sense. I didn't take any pictures just the notes in my book.

 

[KiPod]

Oh, and a Bluetooth box plugs into the Apple 30pin connector to receive signal.

 

[Qtonic]

@KiPod When you hardwired the inputs did you do separate pairs for front and back? I've thought about doing something similar, but I'd like to keep all channels and ideally be able to adjust fade and balance. The amp handles the sub crossover from the line inputs, correct?

 

[KiPod]

I only did right/left. Nothing for front/rear. So, there is no balance/fade on my setup.
The Bluetooth gets the signal to the amp and the amp handles the crossover functions and sends signals for the speakers.

The volume control box I used could also be used as an individual level control which with multiple units could control balance/fade.
You would need to run one knob for master volume and individual knobs for each channel.
It would probably be easier to just install an EQ somewhere.
Unless you want five knobs side by side with individual control (DIY EQ).
I have a hearing aid in my right ear so I don't even try to set up audio the way I used to when I had larger stereo systems.
And no it's not from having larger stereo systems.

 

[Qtonic]

Great info and nice idea, @KiPod

I generally keep balance centered, and that could be adjusted at the source anyway. If I found that front and rear needed adjusting, I might keep this passive splitter with fade adjustment out of the way by the amp just for a little extra control.

What I'd really like to do is keep the stock radio and just tap into the necessary line inputs at the amp for this bluetooth receiver I want to use. The CD player no longer works, so I'd switch to that input and pair my bluetooth. But I'm not sure if that will work/is dangerous/will not damage anything.

MBT-RX

 

[LoftyJZX]

Made this. Hope it helps.

 

[4estLX]

In the Land Cruiser from 98-99, the factory amp and head unit have an isolated ground (Let's call it OAG - OEM Amp Ground). It does NOT act like chassis ground. It is a unique ground used only for the stereo. This ground (OAG) is used for the speaker lines in the factory wiring.

On aftermarket head units it is a completely universal practice for the manufacturer to use the outer casing of the head unit for ground. They will also have a ground wire in the harness. They count on this ground feed to be chassis ground and they count on it being the only ground in the equation.

When you plug in an aftermarket head unit to the LC the new head unit will use chassis ground for its speaker lines, both high and low level. Now you will have chassis ground connected to the factory amp, which is meant to work ONLY with OAG. When you mix the two you will now hear any variance in the two grounds through the speakers as a hiss and whine. Remember, OAG and chassis ground are not the same thing. You want one common ground on the speaker lines. This is NOT POSSIBLE with the 98-99 LC factory amp and an aftermarket head unit without extensive wiring and mounting modification.

Some 100 series seem to not be affected by this, but any system that uses a unique ground in the factory amp setup WILL have issues. You can mask it with inline filters, but they will always diminish the sound quality.

Anytime you're diving into a 100 Series stereo replacement I'd just count on bypassing. See my video below for how I did it. Completely bypassed for very little investment and it's completely reversible if I ever wanted to put the factory stuff back in.

Ok. Thabk you for the vid. Trying to follow but it seems very complicated. I may have to watch a few more times.. Is there any way to do this without removing the seat? 99 LC

 

[suprarx7nut]

Ok. Thabk you for the vid. Trying to follow but it seems very complicated. I may have to watch a few more times.. Is there any way to do this without removing the seat? 99 LC

I don't think so. I guess you could find those wires elsewhere in the chassis and hack into them in a different location, but that's bound to be way more work than just removing the seat. The seat is 4 bolts and a couple connectors.

 

[Todd Atchison]

Hello fellow Forum Members. Wanted to get everyone's expertise on a current pet project I am thinking of doing for my LX 470 HU. The head unit is OEM and is not functioning properly and I am thinking of switching it out with a Pioneer NEX 4200 System. I wanted to get some thoughts on the following things I am looking at:

1. There is a lot of talk about Mark Levinson and Nakamichi stereos, but my HU simply says "Lexus Premium Sound System." Does this mean that my stereo unit is neither of the brand?

2. I am looking to replace the HU with the an Pioneer AVH NEX 4200:
AVH-4200NEX - 2-DIN Flagship Multimedia DVD Receiver with 7" WVGA Touchscreen Display

3. Love to get some guidance on bracketing. Beatsonics seems to sell the bracketing for an aftermarket HU for $120, but I found an ebay seller selling the unit for $49. But love to hear from you guys on whether the brackets are the same:

Beat-Sonic SLA-100fb

LEXUS LX470 1998-2002 Radio Installation Dash Kit Standard 2DIN SATIN BLACK | eBay

4. I would like to keep the factory speakers and AMP. Is the wiring going to complicate anything here?

5. There is alot of talk about the AMP 12V Trigger based on this forum. Is this still needed?

Aftermarket Stereo in 98 LX470 But Keeping Factory Speakers (& Amp, If Applicable)

I appreciate everyone's help! Thanks!

I have a 98 Lexus LX and was also wondering about the original head unit manufacture. I’m going the complete opposite route and staying “stock.” Was the 98 “Lexus Premium Sound“ model made by Nakamichi? I currently use a Bluetooth connection and am perfectly happy. The cassette appears to work but heads need cleaning - the CD player is throwing an error (probably needs cleaned). I’m going pull the unit sometime and give it a go through. Anyone with original HU working hit me up, in case mine is FBR’d. I’ve got a 90‘s mix tape I’m dying to play.

 

[BigGreenLX]

Reviving this thread a bit, I've been happy enough with stock setup on my 98 premium sound system with a bluetooth that plugs into lighter and has charger port as well. When the backlight went out on the head unit I started researching options but it looks like I'm going to figure out how to replace the bulb before I replace my entire sound system.