Ls400 '91 Pioneer Subwoofer Amp Input Gain

Wallybally · August 20, 2014

Hi all,

I've been searching the web and particulaly this forum for any info on the '91 Pioneer system ina my LS.

An new double din radio nav-system with TMC (traffic-info) and DVB-T (Terrestrial Digital TV) are in place, and it works just fine. Connected it using a Metra wire harness for this car, but I'm having trouble getting the subwoofers going.

In the boot I have the Amp on the left, two speakers in the middle (one against the rear seats and one under what we call the hat-tray) , the cd changer on the right.

The cd changer I had to disconnect, because it started making noise, using battery power while the car was locked. First problem solved.

The next thing was, the Subwoofer Amp was making a popping noise when I turned on the ignition.

Also when turning the ignition off again.

After experimenting with the radio's sub output, connecting it to the Amp through the wires behind the radio, the subs were making a lot of popping noise in sync with the music that was playing.

So not working at all.

But I read a very old posting somewhere on this forum that they got it to work.

The question is, how ?

It was working with the old original Pioneer radio. What kind of signal did that give to the Amp ?

Does the Pioneer Amp have an input gain somewhere that will fix this issue ?

I hope someone has some info on this.

For now I have disconnected the Amp as well, so no more popping.

Can someone please dig in to their memory ?

Thanks.

W.

pj8708 · August 21, 2014

Hi Walter and welcome.

Going back that far, I have no personal experience with your edition of the OEM Pioneer stereo.

Your problem could be with the amp as you suspect, or a sympton called "Clipping". When you think about it, your amp may have more playing time on it than actual driving miles. Thats well over 20 years!

Given not only this problem, but the load that the system is going to eventualy take as you put in other updated componets, I would suggest going with a new amp, (confirm this need using an opinion from a local car audio expert.)

If you want to really max out your DIY skills, go to; TIS "Toyota Information Service".; This web site is owned by Toyota and contains any and all information for Lexus, Toyota, and Scion. You can bring up all the electronic and electrical information, as well as wiring diagrams for the radio, and all sound problems. You use the site by renting time and use of the data base. I usually just rent the smallest amount of time which is 2 days, - 48 hours = $ 15.00. That is usually more than enough time to research my problem and mess around with other topics.

Hope others will stop here and give some help.

Paul