I have seen this come up a few times on here before, and as part of my audio build I managed to modify a Performance Sound overhead console, so I can regulate the volume of an aftermarket amplifier to my subwoofer.

Here's what you need:

Performance Sound overhead console.

If using a deck without RCA jacks on it, e.g. a Factory headunit, grab a PAC LC2 High-Level converter.

If using a deck with RCA jacks, you should be able to use the PAC LC1 remote bass knob.

Since I'm using a late-model CD player, I got the PAC LC2. The LC2 converts Speaker level inputs, into the RCA outputs. Here you can see the speaker inputs and RCA outputs:


And the feature we will be taking advantage of, a gain knob:


So, in addition to converting the speaker signal into a low level RCA signal, you can control the gain using the knob, effectively controlling the gain of the subwoofer. What we will be doing is moving that gain function from the PAC unit, into the performance sound overhead.

So to begin, I disassembled the LC2:


This is the gain knob, a 50 kohm stereo linear potentiometer.


So now that I know the rating of the potentiometer, I want to try and find a slide potentiometer with the same rating, that will fit in the overhead console. Here's where I run into a couple issues:

Stereo slider pots appear to be somewhat uncommon, most are only Single pots
Stereo slider pots can be custom ordered to exact specs, but must be purchased in large quantities
Slider pots rated for 50kohms tend to be much larger than the space I have to work with

What I decided to do was find two slider pots, that were as close as possible to the correct size. So here is what I got:
http://www.mouser.com/Searc...p7QMgImaXp%2fw%3d%3d

Two 50kohm Audio Taper (logarithmic) Slide potentiometers, with 30mm of travel. 30mm is still too long, so I won't be able to reach the full volume, but shouldn't be a problem since I can compensate with the gain on the amp.

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So now I have to modify the Performance Sound overhead to accept my new potentiometers.

Here is the original unit as from the factory:


I removed the support bar and pulled out the light switches, leaving just the factory slider:


Here's a test-fit of the new potentiometer. You can see the extra length. The important part, is that the slider can move all the way to the Min volume side, which is the left.


Since the slider screwed right into place, I proceeded to modify the bracket so I can mount the second potentiometer:

Here's the two potentiometers in place:


Next step, I tapered the knob on the center potentiometer, which is the one in the stock location. This allows the stock slider knob to snap right in place. I also removed the white center pieces:


This is the factory knob, notice the cutout on this side? I will use the cutout to link together my two potentiometers.


Here's the knob in place on the center potentiometer, and a dowel connecting both potentiometers together. I afterwards used hot glue to help secure the pieces together and keep the dowel in place:

[This message has been edited by Xanth (edited 02-12-2008).]

Added to FieroDomain here:

http://fierodomain.com/content/view/288/100/

This is a great option to have, looks factory but sounds great with aftermarket equipment.

nice, i have put that on my "wish i had the time, money and expertise" list.

plus for you.

JC

The total cost isn't too bad on just this setup, I got the PAC for about $25 on ebay, the overhead I believe I got for $20, and the resistors for $7 shipped, then another $25 or so in wiring and connectors.

Added all up its actually more than I thought. I was thinking of making up a kit or just doing the mod and shipping it back out to people, I don't expect a huge interest though.

I would be interested in you doing the mod and sending it back. I can't do it now, but I want it done. How much would you charge to do it?

yeah, i'd be interested in doing it as a kit. you send me the bits, i go online to your thread, put it together, and bam.

but i dont have performance sound, i dont have a sub, an amp, or a working car.


but, i am interested in doing something like this in the future. i like that it is very stock looking.

JC

quote Originally posted by Xanth: Added all up its actually more than I thought.

Don't feel bad - everytime i do something cool electric-thing (on my kitcar), it ends up the same way. (especially when you start using the PAC-type black box stuff) VERY nice job

I think I softened the blow by spreading all my parts out over time, when I look back at it my audio build has been fairly costly. Its all good though, I am happy with it

I'm not sure what it would cost for me to assemble this unit for someone, not very much though. Now that I have the pattern down it wouldn't take too long to do.

What I would like to do is make up a kit that can be installed in a normal overhead unit. The performance sound unit appears to be physically the same to a normal 3 button overhead, just the middle button is a slider. So in theory I could modify a regular unit to work, and make a decal of some sort since there are only so many of the factory units around.

i too have done this but it wasnt nearly as technical. my amp came with a gain knob, 3 wires. the perf sound thing also had three wires, the resitance on my amps gain thingie was 0-20kohm and the fieros, which was prolly failing was .5-9kohms and would vary greatly. i just found a sliding potentiometer that went from 0-25kohms, pried out the stock fiero gray slider and stuck it on the new pot and shoved it back in there. the sweep is less, mabye 2/3s what the stock sweep was but it works non the less.

If my amp had a remote knob that's the method I would have used, it is simpler and would result in less signal loss.