2000 Ford Expedition Eddie Bauer Mach audio subwoofer amplifier

[Amp_man46]

I'm wondering if any one has taken apart the factory sub amp and see if there were any potentiometer
on the board for gain settings. I have previously owned a car audio installation shop and currently on the side
I repair car amplifiers. I am an electronics engineer from way back and 12 years ago designed 2 mono car amps.
Anyway if anyone has taken one apart and checked this out please let me know before I do. Thanks

 

[Bazz270]

Gen4 Explorer factory amp

No any settings or tuning options

Just a box with pcb and in/out connector sockets.ive replaced em with JBL amplifier (left factory subwoofer connected)

 

[Amp_man46]

Gen4 Explorer factory amp

No any settings or tuning options

Just a box with pcb and in/out connector sockets.ive replaced em with JBL amplifier (left factory subwoofer connected)

I'm curious to get more power out of the sub amp and as a designer I'm gonna see what I can do to add some more mosfets or BJ transistors to the factory am some time soon. I've designed car amplifiers and got to see what the switching power supply puts out, rail voltages and some other thing but I can do it pretty simply by just adding extra output transistors. We'll see

 

[J_C]

If the amp even has a boost SMPS stage, that voltage and current limit is probably going to need improved before swapping transistors matters, and then with the transistor swap, you may find the heatsink limiting, and have to add another power rail to keep the rest happy at a lower voltage than your output transistors.

If there are no gain pots, probably just a matter of swapping resistor values in an IC feedback loop, or inserting an opamp/preamp gain stage in series with the power amp stage, but without further mods I doubt there is any more gain to be had before raising the voltage.

It might be easier to just keep the original amp for whatever required functions were migrated there from the console head unit then take preamp low level out to an entire separate amp with its own higher power SMPS already built in.

 

[Bazz270]

mine connected to the original audio harness(input came from oem amp wiring and output goes to oem subwoofer).

Grounds taken from one of the chassis bolts and power welding 2awg cable came from the engine bay battery terminal.

 

[traveler]

As long as we're on the subject of a 2000 sub amp. Mine just stopped working, or at least the subwoofer stopped working. I'm assuming the amp stopped driving it. Is there a separate fuse for the amp? in the amp? My long term plans are to replace the factory head unit, the speakers and the sub with newer more modern units. Not all out OMG stuff, just want to replace the worn out stuff and use a single DIN so I have more room for switches.

 

[J_C]

^ I'm not sure if this forum has identified all the factory radio configurations possible in 2nd gen Explorers (for one thing, not too long ago I realized I have a factory rear amp without having a sub at all), but anyway the fuse I see for the premium sound system sub is fuse 29 in the interior fuse box.

You can also measure for whether power (might be a light green/purple wire) (and ground, black/light-green wire) is getting to the amp, whether the amp is outputting low voltage AC to the speaker, and disconnected from the amp, whether the speaker coil has a few ohms resistance or reads open circuit (blown).

If the speaker is blown, I'd also measure for DC voltage on the amp output. There should be VERY near 0.0V DC on the amp output, much more than that suggests an amp fault that blew the speaker. Of course all these readings require playing sound while doing so, except input power to the amp. Fuse 29 is listed as "hot at all times".

 

[J_C]

It's also worth noting that in some stereo configs, the head unit doesn't drive the speakers, instead sends a near line level signal to the same rear amp that drives the subwoofer. In that case you can't just connect a conventional head unit in it's place, unless you reroute all the wires from the speakers to go to the head unit, OR connect the input to the amp to the output to each speaker, except I don't know the wire gauge of the input to the amp, whether it is capable of sufficient current or more like a coax cable only suitable for line level signals.

There's bound to be some topics covering this conversion, once you I.D. which sound system you have. There are wiring diagrams linked below in my sig, including at least 2 different sound systems with an amp driving a sub.

 

[traveler]

I believe you're right about how difficult it is to identify exactly what stereo configuration you have in a 2nd gen. Perhaps a thread to help with that.....

Never mind, it seems that Kris Guilbeaux has made a post that has that covered.

Quick Reference For Audio Forum

The factory-installed sound systems in Ford Explorers are typically offered in three different levels: Base, Premium, and Audiophile The basic elements of the three different levels are: 1) Base systems use a 4X6 Watt Midline radio (AM/FM, AM/FM/Cassette, or AM/FM/CD) with 4 speakers 2)...

www.explorerforum.com

 

[J_C]

^ Thanks for the link, though I question some of that info since it states '98 has the amp integrated to the head unit and it isn't on my '98, and my '98 was nearer the end of '98 production with a build date 9/6/98.