[MikePL]

Here (LINK)is a diagram of the radio-to-amp and radio-to-changer connections. The circled one is the connection to the amp and the connection above it is to the changer. I am interested in the changer connection.

The cables go through the center console and I would like to install a switch which switches the sound signal from the changer to an external source. So I need to cut the signal wires, connect the switch and wires with a mini-jack or other socket.

Question: which are the signal cables? I need three AFAIK:
1. signal ground
2. signal left
3. signal right.

The diagram abbreviations do not make it clear.

[Cattledog]

Well, I had the same question too. My best understanding is that the lexus sound system has 4 seperate channels to each speaker from the radio/head unit. This make's splicing in a 2 channel stereo jack a bit harder while still retaining the 4 channel system. Save yourself some time and buy a fm modulator with stereo jack and call it a day. The cruiser is not a quiet truck on the highway...

[619TOY]

Your link isn't legible but this is where I'd start:

1. I believe what you need is a 4 pole double throw relay.

2. your signal wires which must be interrupted appear to be
R+ GRN
R- BLU
L+ RED
L- WHT

3. the radio side of the wires go the common contacts

4. the changer side of the wire go the NC contacts

5. the aux input wires (3) go to the NO contacts (you will have to parallel the Aux input ground to both - signal contacts.

6. you will need to mount and wire a switch to the coil of the relay. Be sure to use accessory power to switch the relay not constant . That way there's no possibility of draining you battery because you left the switch on.

7. if it were me I would also add a 1A diode across the coil of the relay (stripe towards +) to supress AC spikes when energizing the relay.

8. I would verify the signal wires with a small amplified speaker before performing this procedure. In the US one can find one for about $10 at RadioShack. I don't know if you will have problems with this in Poland.

9. lastly, I've described this procedure as if you have a working knowledge of electronics, if anything is unclear let me know.

10. hope this helps and good luck.

Edit: I've based the wire color info on my '97 EWD

[robmir]

Originally Posted by MikePL

Here (LINK)is a diagram of the radio-to-amp and radio-to-changer connections. The circled one is the connection to the amp and the connection above it is to the changer. I am interested in the changer connection.

The cables go through the center console and I would like to install a switch which switches the sound signal from the changer to an external source. So I need to cut the signal wires, connect the switch and wires with a mini-jack or other socket.

Question: which are the signal cables? I need three AFAIK:
1. signal ground
2. signal left
3. signal right.

The diagram abbreviations do not make it clear.

If you mail or post a clearer image I could try to help you.

1) Is the changer hooked to the radio through a 12 pin connector?
2) The changer display track and name of the song on the radio display ?

[MikePL]

The image is clear in my computer. Maybe your browser is making it smaller. Try to click the image to display it in full size.
The image is the wiring diagram from the FSM and the radio/changer/amp are all stock.
The connections ABOVE the circled area are the ones I am interested in.

The symbols GND, TX-, TX+, CDL-, CDR-, CDL+, CDR+ are abbreviations of the connections to the radio.
The vertical letters O,Y,W,L,R,G represent the cable colors.

619TOY,
your post pretty much explains what I intend to do, but before I start cutting cables, I would like to know if the following abbreviations have this meaning:

CDL- = left-
CDL+ = left+
CDR- = right-
CDR+ = right+

Do I understand it properly?

I wouldn't use a relay to switch the lines. They cause a magnetic field which might be not good for the sound quality. Am I right?

[robmir]

Originally Posted by MikePL

The image is clear in my computer. Maybe your browser is making it smaller. Try to click the image to display it in full size.
The image is the wiring diagram from the FSM and the radio/changer/amp are all stock.
The connections ABOVE the circled area are the ones I am interested in.

The symbols GND, TX-, TX+, CDL-, CDR-, CDL+, CDR+ are abbreviations of the connections to the radio.
The vertical letters O,Y,W,L,R,G represent the cable colors.

619TOY,
your post pretty much explains what I intend to do, but before I start cutting cables, I would like to know if the following abbreviations have this meaning:

CDL- = left-
CDL+ = left+
CDR- = right-
CDR+ = right+

Do I understand it properly?

I wouldn't use a relay to switch the lines. They cause a magnetic field which might be not good for the sound quality. Am I right?

First thing you need to figure out if the Changer left and right output are line level or speaker level. What puzzle me is why the changer has ground for the left and ground for the right output, usually on Toyota or for Toyota radios they use a common ground and the L & R aux hi impedance input (for a changer or external device) is line level.

The only explanation should be that the changer output because of it´s location is balanced low impedance out at line level. This is the same design used for professional long distance audio transmision, for example with wired microphones on audio concerts. This balanced wiring design block RF or electromagnetic interference.

Take in mind that your MP3 device has a common ground unbalanced out.

You would need to source a couple of small audio transformers with balanced 600 Ohm low Z on one side and unbalanced 50 K ohm hi Z on the other side.

I guess you could find them on the stores that sell PA equipment, broadcast equipment or a professional music store .

You will have two wires on the hi impedance side of each transformer, one will be used as ground and the other as signal (either as input or ouput).

Joint together both transformers ground of the hi impedance side to the common MP3 ground and to the radio pin 3 which is your signal ground. Connect the remaining Hi imp wire of one transformer to the left MP3 out and the other to right MP3 out.

Now you have on the lower impedance side of the transformer 2 wires on each one to be used as balanced input or output.

Use one of the same color from each transformer: one for the CDL - and one for the CDR -.

Use the remaining wire of each transformer (should have another color or number because you need to keep on the same phase both channeles) for the respective CDL+ and CDR+.

With this you are converting the hi impedance unbalanced out of your MP3 or ipod (3 wires) to the Lexus low impedance balanced radio input ( 4 wires plus ground).

You can use either a 4 pole 2 position switch with NO/NC contacts or you can use a 12 volt 4 pole NO / NC relay (look for a high impedance coil). I bet You will not have any induced noise because of the way the audio signal is handled.

Now in a perfect world you should find a way to turn off the changer to avoid any unnecesary wear and tear but trick the radio as if the changer is hooked and turned on, so the changer input in the radio is selected and that´s the purpose of the logic input wires 9 and 10 on the radio marked as TX- and TX + which send back to the radio the changer status.

And here is my friend, were I stop !!!!!!!!!!!

As I recall there is a couple of non expensive devices available in the market which provide you with an aux input but you can´t use the changer anymore. And there is also a couple of very expensive adapters to interface an ipod to your Lexus radio allowing you to control the ipod from the Lexus and display track and song titles on your OEM radio display.

[619TOY]

Originally Posted by MikePL

The image is clear in my computer. Maybe your browser is making it smaller. Try to click the image to display it in full size.
The image is the wiring diagram from the FSM and the radio/changer/amp are all stock.
The connections ABOVE the circled area are the ones I am interested in.

The symbols GND, TX-, TX+, CDL-, CDR-, CDL+, CDR+ are abbreviations of the connections to the radio.
The vertical letters O,Y,W,L,R,G represent the cable colors.

619TOY,
your post pretty much explains what I intend to do, but before I start cutting cables, I would like to know if the following abbreviations have this meaning:

CDL- = left-
CDL+ = left+
CDR- = right-
CDR+ = right+

Do I understand it properly?

I wouldn't use a relay to switch the lines. They cause a magnetic field which might be not good for the sound quality. Am I right?

I believe this info is correct. You have interpreted it the same as I have. I would try the relay and not be worried any magnetic field. what you need to worry about with a relay is the AC spike caused by the coil of the relay, hence the diode. My buddy just did this on his ES300 a couple weeks ago and it worked out well. The wire colors were however, different.

Originally Posted by robmir

First thing you need to figure out if the Changer left and right output are line level or speaker level. What puzzle me is why the changer has ground for the left and ground for the right output, usually on Toyota or for Toyota radios they use a common ground and the L & R aux hi impedance input (for a changer or external device) is line level.

The only explanation should be that the changer output because of it´s location is balanced low impedance out at line level. This is the same design used for professional long distance audio transmision, for example with wired microphones on audio concerts. This balanced wiring design block RF or electromagnetic interference.

Take in mind that your MP3 device has a common ground unbalanced out.

You would need to source a couple of small audio transformers with balanced 600 Ohm low Z on one side and unbalanced 50 K ohm hi Z on the other side.

I guess you could find them on the stores that sell PA equipment, broadcast equipment or a professional music store .

You will have two wires on the hi impedance side of each transformer, one will be used as ground and the other as signal (either as input or ouput).

Joint together both transformers ground of the hi impedance side to the common MP3 ground and to the radio pin 3 which is your signal ground. Connect the remaining Hi imp wire of one transformer to the left MP3 out and the other to right MP3 out.

Now you have on the lower impedance side of the transformer 2 wires on each one to be used as balanced input or output.

Use one of the same color from each transformer: one for the CDL - and one for the CDR -.

Use the remaining wire of each transformer (should have another color or number because you need to keep on the same phase both channeles) for the respective CDL+ and CDR+.

With this you are converting the hi impedance unbalanced out of your MP3 or ipod (3 wires) to the Lexus low impedance balanced radio input ( 4 wires plus ground).

You can use either a 4 pole 2 position switch with NO/NC contacts or you can use a 12 volt 4 pole NO / NC relay (look for a high impedance coil). I bet You will not have any induced noise because of the way the audio signal is handled.

Now in a perfect world you should find a way to turn off the changer to avoid any unnecesary wear and tear but trick the radio as if the changer is hooked and turned on, so the changer input in the radio is selected and that´s the purpose of the logic input wires 9 and 10 on the radio marked as TX- and TX + which send back to the radio the changer status.

And here is my friend, were I stop !!!!!!!!!!!

As I recall there is a couple of non expensive devices available in the market which provide you with an aux input but you can´t use the changer anymore. And there is also a couple of very expensive adapters to interface an ipod to your Lexus radio allowing you to control the ipod from the Lexus and display track and song titles on your OEM radio display.

I don't believe the outputs of the changer to be balanced. You typically need 3 conductors per channel for a balanced system. As I've said, my buddy did this to his ES300 a couple weeks ago and it works fine.

Hope this helps. Gotta get back to work

[robmir]

Originally Posted by 619TOY

I believe this info is correct. You have interpreted it the same as I have. I would try the relay and not be worried any magnetic field. what you need to worry about with a relay is the AC spike caused by the coil of the relay, hence the diode. My buddy just did this on his ES300 a couple weeks ago and it worked out well. The wire colors were however, different.

I don't believe the outputs of the changer to be balanced. You typically need 3 conductors per channel for a balanced system. As I've said, my buddy did this to his ES300 a couple weeks ago and it works fine.

Hope this helps. Gotta get back to work

That´s your opinion, but unfortunately you are wrong because you can have a balanced system with only two wires

A simple example: After the widely use of UTP-5, yes the cable you use to hook your ethernet port from you computer to your router or switcher, now there are several companies which manufacture what they call baloons ( 3 or 4 small transformers inside a blackbox each one using a twisted pair of the 4 available on the UTP-5 hooked to the balanced side of each transformer and a unbalanced out for audio or video) and connect them on each end of a up to 2200 ft long UTP-5 ( a cable with 4 non shielded twisted pairs).

This black box has either two RCA for left and right and a BNC for component video or a s/video socket and a RJ-45 8 pin ethernet connector.

Take two of this babies and you can relay very good quality component or s/video plus audio for up to 2200 ft of distance without your third ground wire.

As a retired Electronic Engineer with many years in the broadcasting field, let me tell you we did many rack installations were we need to disconnect one end of the ground wire (your missing third wire) between two balanced input/output devices specially when cascading many of them, because what´s called ground loop, which in our case didn´t create noise but something worst: voltage spikes at the latest hooked equipment which sometimes ended fried.

Now take in mind that Lexus choose to add a common shield over the 4 balanced wires between the cd changer and the radio, because vehicle enviroment is more prone to create EMI and the changer is far from the radio. Remember Lexus identified the wires as + and - for left and right channel besides the shield ground, something you found only when you work with low level signal which will be later amplified !!!!

The polarity of course must be the same on both channels because out of phase signals could cancel the bass.

The wires between the Lexus radio and the Lexus amp are not balanced, they have one wire for each of the 4 channel amp and only one common signal ground which shields all 4 wires.

[619TOY]

Originally Posted by robmir

That´s your opinion, but unfortunately you are wrong because you can have a balanced system with only two wires

A simple example: After the widely use of UTP-5, yes the cable you use to hook your ethernet port from you computer to your router or switcher, now there are several companies which manufacture what they call baloons ( 3 or 4 small transformers inside a blackbox each one using a twisted pair of the 4 available on the UTP-5 hooked to the balanced side of each transformer and a unbalanced out for audio or video) and connect them on each end of a up to 2200 ft long UTP-5 ( a cable with 4 non shielded twisted pairs).

This black box has either two RCA for left and right and a BNC for component video or a s/video socket and a RJ-45 8 pin ethernet connector.

Take two of this babies and you can relay very good quality component or s/video plus audio for up to 2200 ft of distance without your third ground wire.

As a retired Electronic Engineer with many years in the broadcasting field, let me tell you we did many rack installations were we need to disconnect one end of the ground wire (your missing third wire) between two balanced input/output devices specially when cascading many of them, because what´s called ground loop, which in our case didn´t create noise but something worst: voltage spikes at the latest hooked equipment which sometimes ended fried.

Now take in mind that Lexus choose to add a common shield over the 4 balanced wires between the cd changer and the radio, because vehicle enviroment is more prone to create EMI and the changer is far from the radio. Remember Lexus identified the wires as + and - for left and right channel besides the shield ground, something you found only when you work with low level signal which will be later amplified !!!!

The polarity of course must be the same on both channels because out of phase signals could cancel the bass.

The wires between the Lexus radio and the Lexus amp are not balanced, they have one wire for each of the 4 channel amp and only one common signal ground which shields all 4 wires.

I realize that you can have a balanced system without 3 wires. This is why I said "typically". When you omit the shield you merely have the two signal wires, one of which is in phase and one of which is out of phase.

You are correct, this particular system IS a balanced system. When I get around to doing my AUX input I will use a device I already own to convert the unbalanced signal of my ipod into a balanced signal. Hopefully you will be willing to spend as much time helping Mike with this mod as you have explaining to me that I'm wrong.

[MoJ]

Before you cut up your wiring you might check out PIE to see if they have an adapter harness. I bought one for another vehicle that plugged into the factory port and allowed use of both the changer and and any other device I want to plug into it. Way better than FM modulation as well.

http://www.pie.net/

[619TOY]

Originally Posted by MoJ

Before you cut up your wiring you might check out PIE to see if they have an adapter harness. I bought one for another vehicle that plugged into the factory port and allowed use of both the changer and and any other device I want to plug into it. Way better than FM modulation as well.

http://www.pie.net/

That's a great idea. I spent a little time researching it but it seems no aftermaket companies are interested in getting signal from an ipod into a ten year old vehicle.

[nakman]

Scion head unit?

[robmir]

Originally Posted by 619TOY

That's a great idea. I spent a little time researching it but it seems no aftermaket companies are interested in getting signal from an ipod into a ten year old vehicle.

Besides PIE there is Soundgate and a couple of other which I don't recall.

This adapters are to be plugged in the 12 pin radio port were the CD changer were hooked before.

AFAIK they will not work on pre 2003 Toyota vehicles.

On the latest Toyota / Scion Radios this 12 pin port is were the optional XM tuner is suposed to be hooked.

Any how I got (for my son's 2007 Yaris coupe) on ebay from a a 2006 XA Scion, the Pioneer standard head unit (not the ipod version which is too expensive even used) which got the 20 pin aux input pigtails from the donor vehicle.

I added a 2.2 K resistor between two of the pins and a couple of RCA female plugs and now it has aux input for his ipod line out dock adapter.

Latest Toyota / Scion vehicles use a wider head unit and the dash board on the 80 series must be trimmed. I pass on that.

[robmir]

Originally Posted by 619TOY

I realize that you can have a balanced system without 3 wires. This is why I said "typically". When you omit the shield you merely have the two signal wires, one of which is in phase and one of which is out of phase.

You are correct, this particular system IS a balanced system. When I get around to doing my AUX input I will use a device I already own to convert the unbalanced signal of my ipod into a balanced signal. Hopefully you will be willing to spend as much time helping Mike with this mod as you have explaining to me that I'm wrong.

Not a problem

Let me know your input once you did your mod.

What buzz me is when enough is enough as to brainstorm mods to a 10 year old head unit ?

But will the latest gadget satisfy you !!!!

For example looking to simplify the life of a friend, on his Toyota we installed the latest Sony head unit which include bluetooth and ipod control (it just needed one extra blackbox for the ipod) , installation was a breeze but this all in one have serious issues : the ipod interface is not good and the bluetooth has severe limitations because it's noisy and it's firmware can't be upgraded to cover new phones and features.

In short words there is not a perfect world !!!! well not so fast buddy.

Once I saw a demo of the newest venture of Bill Gates and Ford in the last CES for a astonishing computer based head unit which combines bluetooth interface and usb input ports for voice command of both the cell phone dialing and to select any digital tracks (downloaded from the ipod or Zen to the hard disk on the head unit) by name, artist, album or track number I ended gaga