Pre-Amp Outputs Tapped on Stock Bose
12-08-2003, 02:57 PM
#1
Registered User
Thread Starter
Pre-Amp Outputs Tapped on Stock Bose
If this is old news, then please forgive me for the double post.
So far, every audio install I have seen for the 8 simply uses a Hi/Lo converter to tap onto the speakers in the rear deck. Although this is a perfectly fine approach (and an easy one at that), it’s always better to tap a direct low-level line if possible. Several have asked if this can be done, and last night rotarygod and I managed to prove that it can.
The colors in the attached diagram do not match the wire colors (because those wire colors are two-tone). But the diagram clearly shows you which pin in the stock amp header is which signal. I’ll list the stock wire colors here also so you don’t have to look it up in the header if you don’t want to.
Also, please be aware that we never tested the rear connections to be sure, but they should be accurate (we’re going off of the Mazda wiring diagram). Please PM me if they are not. We used the front signal because the front channel drives the 9” subs. Although, it doesn’t look like there is any difference between the front channel signal and the rear channel signal. So, if you want to use the rear channel to make your subs on the rear fader with the back deck, you should be able to.
Left Front +: R / L
Left Front -: LG / R
Right Front +: L / W
Right Front -: Y / G
Left Rear +: G / O
Left Rear -: L / O
Right Rear +: GY / R
Right Rear -: BR / R
(words added for search engine: preamp pre-amp RCA)
So far, every audio install I have seen for the 8 simply uses a Hi/Lo converter to tap onto the speakers in the rear deck. Although this is a perfectly fine approach (and an easy one at that), it’s always better to tap a direct low-level line if possible. Several have asked if this can be done, and last night rotarygod and I managed to prove that it can.
The colors in the attached diagram do not match the wire colors (because those wire colors are two-tone). But the diagram clearly shows you which pin in the stock amp header is which signal. I’ll list the stock wire colors here also so you don’t have to look it up in the header if you don’t want to.
Also, please be aware that we never tested the rear connections to be sure, but they should be accurate (we’re going off of the Mazda wiring diagram). Please PM me if they are not. We used the front signal because the front channel drives the 9” subs. Although, it doesn’t look like there is any difference between the front channel signal and the rear channel signal. So, if you want to use the rear channel to make your subs on the rear fader with the back deck, you should be able to.
Left Front +: R / L
Left Front -: LG / R
Right Front +: L / W
Right Front -: Y / G
Left Rear +: G / O
Left Rear -: L / O
Right Rear +: GY / R
Right Rear -: BR / R
(words added for search engine: preamp pre-amp RCA)
Last edited by eXentric; 12-16-2003 at 10:54 AM.
12-08-2003, 03:46 PM
#3
Registered User
To be honest, I am surprised that this connection scheme worked.
Typically the signals from head-units are differential in nature. This means that instead of L- and R- signals being connected to ground, they usually have an inverted single that is 180 degrees out of phase with the L+ and R+.
By connecting the L- and R- to the shields of the RCA cables and then connecting those cables to your amp, you should have shorted out those signals which would normally cause a variety of effects ranging from the head-unit going into some sort of protection mode, the head-unit being damaged, or the signal becoming mono or more mono for the rest of the system.
Since the Bose equipt RX-8's get the same headunit as the non-Bose RX-8's, I wonder if the headunit senses the Bose and makes its outputs single-ended and not differential accordingly.
For anyone else who tries this and doesn't get good results, try connecting ground to your two RCA shield connections.
But, hey, if it works it works.
-Mr. Wigggles
Ps. eXentric, make sure to turn your Audio pilot off now that you have subs. It screws things up at low volumes.
Typically the signals from head-units are differential in nature. This means that instead of L- and R- signals being connected to ground, they usually have an inverted single that is 180 degrees out of phase with the L+ and R+.
By connecting the L- and R- to the shields of the RCA cables and then connecting those cables to your amp, you should have shorted out those signals which would normally cause a variety of effects ranging from the head-unit going into some sort of protection mode, the head-unit being damaged, or the signal becoming mono or more mono for the rest of the system.
Since the Bose equipt RX-8's get the same headunit as the non-Bose RX-8's, I wonder if the headunit senses the Bose and makes its outputs single-ended and not differential accordingly.
For anyone else who tries this and doesn't get good results, try connecting ground to your two RCA shield connections.
But, hey, if it works it works.
-Mr. Wigggles
Ps. eXentric, make sure to turn your Audio pilot off now that you have subs. It screws things up at low volumes.
Last edited by MrWigggles; 12-08-2003 at 03:49 PM.
12-10-2003, 09:54 PM
#5
Registered User
Thread Starter
I *think* so, but does the non-bose have the rear-mounted amp? If not, you can follow the diagrams and match the pins on the head unit. It would require the header and more work.
Sorry, I have the Bose, so I don't know what it looks like without it.
eXe
Sorry, I have the Bose, so I don't know what it looks like without it.
eXe
12-13-2003, 08:29 AM
#6
Wut da F Y'all lookin' @!
Re: Pre-Amp Outputs Tapped on Stock Bose
Originally posted by eXentric
If this is old news, then please forgive me for the double post.
So far, every audio install I have seen for the 8 simply uses a Hi/Lo converter to tap onto the speakers in the rear deck. Although this is a perfectly fine approach (and an easy one at that), it’s always better to tap a direct low-level line if possible. Several have asked if this can be done, and last night rotarygod and I managed to prove that it is.
The colors in the attached diagram do not match the wire colors (because those wire colors are two-tone). But the diagram clearly shows you which pin in the stock amp header is which signal. I’ll list the stock wire colors here also so you don’t have to look it up in the header if you don’t want to.
Also, please be aware that we never tested the rear connections to be sure, but they should be accurate (we’re going off of the Mazda wiring diagram). Please PM me if they are not. We used the front signal because the front channel drives the 9” subs. Although, it doesn’t look like there is any difference between the front channel signal and the rear channel signal. So, if you want to use the rear channel to make your subs on the rear fader with the back deck, you should be able to.
Left Front +: R / L
Left Front -: LG / R
Right Front +: L / W
Right Front -: Y / G
Left Rear +: G / O
Left Rear -: L / O
Right Rear +: GY / R
Right Rear -: BR / R
(words added for search engine: preamp pre-amp RCA)
If this is old news, then please forgive me for the double post.
So far, every audio install I have seen for the 8 simply uses a Hi/Lo converter to tap onto the speakers in the rear deck. Although this is a perfectly fine approach (and an easy one at that), it’s always better to tap a direct low-level line if possible. Several have asked if this can be done, and last night rotarygod and I managed to prove that it is.
The colors in the attached diagram do not match the wire colors (because those wire colors are two-tone). But the diagram clearly shows you which pin in the stock amp header is which signal. I’ll list the stock wire colors here also so you don’t have to look it up in the header if you don’t want to.
Also, please be aware that we never tested the rear connections to be sure, but they should be accurate (we’re going off of the Mazda wiring diagram). Please PM me if they are not. We used the front signal because the front channel drives the 9” subs. Although, it doesn’t look like there is any difference between the front channel signal and the rear channel signal. So, if you want to use the rear channel to make your subs on the rear fader with the back deck, you should be able to.
Left Front +: R / L
Left Front -: LG / R
Right Front +: L / W
Right Front -: Y / G
Left Rear +: G / O
Left Rear -: L / O
Right Rear +: GY / R
Right Rear -: BR / R
(words added for search engine: preamp pre-amp RCA)
The following users liked this post:
Nuke It (07-31-2021)
12-13-2003, 10:21 AM
#7
Registered User
Thread Starter
No. The only pins on the amplifier are battery (which is constantly on).
There has been some talk in this thread about a possible switched ACC plug on the back of the head unit, but it hasn't yet been confirmed.
If you need an easy way out, check out this thread for pictures of connecting to the accessory plug near the back seat. This will give you a switched input with the accessory on the ignition but unfortunately separate from the head unit. You may want to have a remote bass **** installed for starting the car because mine pops fairly loudly when I have the amp turned up at all and I start my car.
There has been some talk in this thread about a possible switched ACC plug on the back of the head unit, but it hasn't yet been confirmed.
If you need an easy way out, check out this thread for pictures of connecting to the accessory plug near the back seat. This will give you a switched input with the accessory on the ignition but unfortunately separate from the head unit. You may want to have a remote bass **** installed for starting the car because mine pops fairly loudly when I have the amp turned up at all and I start my car.
12-14-2003, 07:23 AM
#8
Wut da F Y'all lookin' @!
Originally posted by eXentric
No. The only pins on the amplifier are battery (which is constantly on).
There has been some talk in this thread about a possible switched ACC plug on the back of the head unit, but it hasn't yet been confirmed.
If you need an easy way out, check out this thread for pictures of connecting to the accessory plug near the back seat. This will give you a switched input with the accessory on the ignition but unfortunately separate from the head unit. You may want to have a remote bass **** installed for starting the car because mine pops fairly loudly when I have the amp turned up at all and I start my car.
No. The only pins on the amplifier are battery (which is constantly on).
There has been some talk in this thread about a possible switched ACC plug on the back of the head unit, but it hasn't yet been confirmed.
If you need an easy way out, check out this thread for pictures of connecting to the accessory plug near the back seat. This will give you a switched input with the accessory on the ignition but unfortunately separate from the head unit. You may want to have a remote bass **** installed for starting the car because mine pops fairly loudly when I have the amp turned up at all and I start my car.
12-14-2003, 12:42 PM
#9
Registered
The popping noise is due to the ignition hot wire that is used for remote turn on. We could rewire it through and relay with constant power and use the ACC as the relay tripping signal. This should end the popping noise.
12-14-2003, 04:34 PM
#10
Registered User
Thread Starter
Rotary,
I'd like to talk about doing this when you have time. I also have a couple of other questions I'd like to ask you offline. Please PM me when you think you'll have time before or after the holidays.
I'd like to talk about doing this when you have time. I also have a couple of other questions I'd like to ask you offline. Please PM me when you think you'll have time before or after the holidays.
02-14-2004, 09:38 PM
#11
Mmmmm... Rotary Donut
Join Date: Nov 2003
Location: Lake in the Hills, IL (NW Chicago Burbs)
Posts: 2,376
Likes: 0
Received 4 Likes
on
2 Posts
FYI- the rear pin-outs work perfectly- thanks guys! I took a few pics of the wiring details and posted here as an ammendment to my custom speakerbox build post:
https://www.rx8club.com/showthread.p...threadid=19906
Thanks again for the info...
-Sean
https://www.rx8club.com/showthread.p...threadid=19906
Thanks again for the info...
-Sean
04-10-2004, 11:46 AM
#12
Registered User
Thread Starter
If you've been following other threads, you may have noticed that some users had problems with this method of connecting their amps. One user even feels that this connection fried his head unit. Just to play it safe, I decided to try hooking it up the other way. It only cost me $40, and here are my results (cross-post):
I must agree. I purchased the N-774v and installed it last week. I didn't get a chance to post about it until today.
Overall, I'm actually happier with this install then I was with the direct 'preamp' connection I had before. Not only is this approach safer, but I actually do get more bass out of the system now.
Unfortunately, the bass is not as clean as it was before. It sounds a bit more 'muddy' but I still feel it's worth it. I can now agree with the people that argue the Bose amplifier in the rear deck modifies the sound from the head unit. And I think it modifies it quite a bit. Now I'm wondering if it would make a difference if I hooked up to the front speaker outputs rather then the rear ones...
One last note, mdw33333 posted this:
These are the wire colors at the speakers themselves. I used this guide, but when I connected it to the amplifier one side was out of phase. I don't know if these pinouts were backwards or if something inside the N-774v I received was backwards. At any rate, I clipped off the connectors to the Pink and Purple wires on the left side and swapped them (Pink + and Purple -) and everything got much louder.
So, all in all, I would reccommend this approach and I would recommend the N-774v.
eXe
Did I miss where the N-774v could be purchased?
http://www.davidnavone.com
You can use any line level converter, but these seem to be good.
You can use any line level converter, but these seem to be good.
Overall, I'm actually happier with this install then I was with the direct 'preamp' connection I had before. Not only is this approach safer, but I actually do get more bass out of the system now.
Unfortunately, the bass is not as clean as it was before. It sounds a bit more 'muddy' but I still feel it's worth it. I can now agree with the people that argue the Bose amplifier in the rear deck modifies the sound from the head unit. And I think it modifies it quite a bit. Now I'm wondering if it would make a difference if I hooked up to the front speaker outputs rather then the rear ones...
One last note, mdw33333 posted this:
When tapping the rear speakers, use these colors:
Left Rear + is Purple
Left Rear - is Pink
Right Rear + is Black/Blue
Right Rear - is White/blue
Left Rear + is Purple
Left Rear - is Pink
Right Rear + is Black/Blue
Right Rear - is White/blue
So, all in all, I would reccommend this approach and I would recommend the N-774v.
eXe
The following users liked this post:
Nuke It (07-31-2021)
04-10-2004, 11:48 AM
#13
Registered User
Thread Starter
I'd like to merge this thread with the other one. If you want to reply, please reply to the Line Converters: Adding an Amp to the Head Unit thread.
07-31-2021, 04:29 PM
#14
Registered
As noted by eXentric on post #12, I too was having issues with volume output from my sub / amp combo:
.
My sub/amp has a High Level input (or a built in High Level to Low Level converter). I swapped the rear left speaker High leads as described above, and now the amp works correctly.
.
Thanks eXentric for the post!
.
"These are the wire colors at the speakers themselves. I used this guide, but when I connected it to the amplifier one side was out of phase. I don't know if these pinouts were backwards or if something inside the N-774v I received was backwards. At any rate, I clipped off the connectors to the Pink and Purple wires on the left side and swapped them (Pink + and Purple -) and everything got much louder."
.My sub/amp has a High Level input (or a built in High Level to Low Level converter). I swapped the rear left speaker High leads as described above, and now the amp works correctly.
.
Thanks eXentric for the post!
Last edited by Nuke It; 07-31-2021 at 04:31 PM.
Thread
Thread Starter
Forum
Replies
Last Post
hornet279
Series I Interior, Audio, and Electronics
19
04-07-2012 06:03 PM
Chronisseur
Series I Interior, Audio, and Electronics
6
07-18-2010 06:22 PM
Rambot958
Series I Interior, Audio, and Electronics
2
03-17-2005 05:55 PM
irfan
Series I Interior, Audio, and Electronics
0
10-31-2004 11:50 AM
