[l3cliclcly]

I recently went to Best Buy and Circuit City planning on purchasing a new headunit for my '94 NA Supra. They told me that they would sell and install me one, but said that they would have to disable the stock amplifier in order to do this for another FIFTY DOLLARS!?!!?!. It seemed a little absurd to me, so I decided I'd ask you guys before making any decisions. Does this stock amplifier NEED to be disabled for a new headunit. I already have new door speakers and rear speakers in. They disabled the rear 5x7 b/c I plan on doing subs. Just please let me know if there are ANY how-to's on disabling this stock amp so I can save some money or let me know if they are just bullshitting me.

Thank you

 

[Craig King]

All you have to do is disconnect the wiring harnesses from the amp.

 

[l3cliclcly]

So basically just take out all of the wires that are connected to the amplifier right now? Sorry I'm clueless on all of this, I just don't feel like being ripped off from a store for "disabling" stock amp for a headunit!

Thank you! More info would be great

 

[DJ dZ]

They are ripping you off! To disable the stock amp simply remove the wiring harnesses out from the back of the stock HU as Craig said

 

[brianb]

Damn, too bad you aren't closer. For the prices you pay at retail stores, you can usually make your $$$ go 2 or 3 times as far if you shop online; higher end models, etc. On caveat though, most, if not all companies will not honor any online purchases.

If you take the time to read around, you can find a wealth of resources to help narrow down equipment.


Most of the time, when you installed an aftermarket headunit, you plug directly into where the stock amplifier unplugs. Doing this results in losing the subwoofer in the back, since most headunits only support 4 channels. Front left, front right, rear left, and rear right. The amp in the supra supports power for 7 speakers (channels), and crosses the frequencies over appropriately.


Brian

 

[Guest]

Brian you seem to be very knowledgeable about ICE. Both in general and supra specific.

You say the stock supra amp supports 7 channels ? What are the extra 2 channels. I count only 5 (front left and right, rear left and right and sub)

Does the supra have 2 wiring setups, 1 if you use the amp and 1 if you bypass the amp ?

When I got my supra, I removed the stereo as it was japanese (I'm in the UK), I bought a wiring harness to fit a standard ISO connector and plugged it into 2 white connectors. With this I bypassed the amp. The amp is still under the seat as I read people having problems with the electric aerial, if the amp is removed.

 

[Supra-Holic]

I know that the Supra has 2 tweets, 2 mids, 2 rear speakers and a sub. But the amp only has 5 channels or at least my does (94TT).

 

[brianb]

Brian you seem to be very knowledgeable about ICE. Both in general and supra specific.

You say the stock supra amp supports 7 channels ? What are the extra 2 channels. I count only 5 (front left and right, rear left and right and sub)

Does the supra have 2 wiring setups, 1 if you use the amp and 1 if you bypass the amp ?

When I got my supra, I removed the stereo as it was japanese (I'm in the UK), I bought a wiring harness to fit a standard ISO connector and plugged it into 2 white connectors. With this I bypassed the amp. The amp is still under the seat as I read people having problems with the electric aerial, if the amp is removed.

The tweets in the dash are the 2 extra channels. I haven't confirmed it, but I think they're either crossed over at the amp (hence the 7 channel theory), OR there's an inline filter somewhere on the wires leading up to the dash.

The 2 connectors under the headunit lead straight down to the amp. I believe the smaller of the two lead to the rear speakers. It's been a while since I've studied the stock wiring. I once wired in a 4 channel using the stock amp as the input, but eventually removed all the stock equipment.

I should note that the stereo upgrades should be done in this fashion: If you plan to upgrade the headunit, you might as well upgrade to a 4/2 channel amplifier while you're at it. While the dash is apart, you can have rca patch cables run, etc. I've opened up the dash enough times to where I can probably remove a stock headunit in about 5 minutes, or less. LOL.

For the front spoiler, if people are experiencing problems, then it might be wired to the amp as a remote on/relay for power. You might have to experiment to see which (extra) wires are wired up for the front spoiler, and then possibly hook up a relay to replace the stock amp.

Brian

 

[Howie]

They aint realy ripping him off cuz if they do it right they have to disconnect the stock amp and then splice the stock wires to catch the feeds from the stock speaker wires. This aint no 10 minute job you know. I did it in my old 95 3KGT and it was a b*#$& I wouldn't wanna do it again. And I doubt that any stock amp comes 7 channels. They would have to run off of 5 channels at the most no matter how many speakers come stock in the car.

 

[MoogieBoogie]

Doesn't the Metra harness bypass the factory amplifier?

 

[Roadie8105]

From what I remember the Metra harness does eliminate the use of the OEM amp and uses power off head unit for speakers... What Circuit City is talking about is bypassing the amp (wiring harness and labor) and not simply unplugging it.. The best thing I found was to purchase a 5 ch amp (like an Alpine) with built in crossover controls and mount it it place of OEM amp.. This will run speakers perfectly that are currently in car and give you crossed over rear sub output to run sub so you don't loose it... Or I guess you could run speakers off radio output and sub off a small seperate amp...

 

[Guest]

Hey

Been reading various posts about removing the stock amp. It seems that the amp also has some control over the power antenna.

Parboy has posted this

I believe that the antenna relay sends a signal thru the stock amp harness under the pass seat, then on to the antenna. The guys that installed my stuff had to do something with the wiring under the seat to get it to work correctly.

Can anybody confirm this ?

 

[l3cliclcly]

I'm not sure, My antenna is taken out and shaved with paint over it....so I wouldn't know....

So what would be the absolute EASIEST way to avoid the 50 dollar price of getting stock amp disabled?

 

[Roadie8105]

AFAIK, the power antenna only interfaces into box that sits atop the radio mounting bracket and nothing to do with under the seat...

I guess you could go ahead and buy aftermarket 5 ch amp to run whole system.. You will not have OEM sub working if you only hook the fronts and rears off the new radio.. Unless there is some new kind of 'creative' wiring that can be done.. The $50 is probably for wiring harness ($15) plus $35 in labor which is not unreasonable considering what is involved...

 

[DawgStyleMKIV]

I'm pretty certain that the crossovers for the tweets are not part of the stock amp. I installed an Alpine headunit and the tweets work just fine. Power antenna also works fine as well. The wiring harness that you are looking for are on the bottom right of the center console, next to the passengers foot where the carpet meets the center console. (Best I can explain.) To install an aftermarket headunit, get the wiring harness SET. There should be two seperate harnesses that match with two that go to the stock amp.

 

[RScott]

They aint realy ripping him off cuz if they do it right they have to disconnect the stock amp and then splice the stock wires to catch the feeds from the stock speaker wires. This aint no 10 minute job you know. I did it in my old 95 3KGT and it was a b*#$& I wouldn't wanna do it again. And I doubt that any stock amp comes 7 channels. They would have to run off of 5 channels at the most no matter how many speakers come stock in the car.

that sounds like a pretty supra/stereo specific uneducated comment...no offense

its been pretty much said...go with either a schoshe or metra aftermarket harness so that you dont need to hack any wires at all aside from finding out about the front spoiler relay...
when you pull out the headunit...follow its wires...you should find another plug that will fit into the aftermarket harness (two pieces...one large and one small).

if anything...what you can do is pull the seat out...remove the stock amp from the car completely...pull the harness to the stock amp on the front of it up through the carpet to the dash section...leave the other plug into it as is(this will disable the sub unfortunately as well)...remove that completely and youll be left with what you want to plug into the aftermarket harnesses. then after soldering the metra/schoshe harness to the headunit harness as per color code it should be plug and play.
On Brians note, If you plan to run an aftermarket amp in the future you can run the rcas to the back and cap them off for now as well as the remote turn on to save time later

 

[Guest]

RScott, Brianb, DawgStyleMKIV, Roadie8105 ....

I have fitted a wiring harness so that an aftermarket stereo with an ISO connector works. It's not the metra/schoshe referred to in the posts, but by Autoleads. In in the UK and I have a JDM Supra.

However some of the posts mention the front spoiler. The harness I have used, still leaves the front spoiler working. Is this because I still have the stock amp still wired up ?

I'm going to get an amp in the next couple of weeks fitted. It is likely to be a Genesis profile P4. Due to its size it probably won't be fitted under the seat in place of the stock amp.

 

[l3cliclcly]

Appreciate EVERYONE's comments,

Thank you

 

[Howie]

that sounds like a pretty supra/stereo specific uneducated comment...no offense

its been pretty much said...go with either a schoshe or metra aftermarket harness so that you dont need to hack any wires at all aside from finding out about the front spoiler relay...
when you pull out the headunit...follow its wires...you should find another plug that will fit into the aftermarket harness (two pieces...one large and one small).

if anything...what you can do is pull the seat out...remove the stock amp from the car completely...pull the harness to the stock amp on the front of it up through the carpet to the dash section...leave the other plug into it as is(this will disable the sub unfortunately as well)...remove that completely and youll be left with what you want to plug into the aftermarket harnesses. then after soldering the metra/schoshe harness to the headunit harness as per color code it should be plug and play.
On Brians note, If you plan to run an aftermarket amp in the future you can run the rcas to the back and cap them off for now as well as the remote turn on to save time later

no offense taken but i was looking at it from the Circuit city point of view and why they would charge him that much to do it. That would be the only reason to do so.