Woods

I thought I'd be able to run the factory infinity amp with my aftermarket HU, but so far, no. But with all the work I have into wiring this thing, I'm not giving up yet.

I see that the factory infinity amp will run in "legacy" mode. Details can be found on the PDF link at the following web page: AMP DETAILS

I've tried shorting pin ADSEL to the ground, hoping that this thing would power on, but no luck. I don't know how to address the STB setting though.

If anybody has got this amp to run in legacy mode, then please add some details.

Meanwhile, I'm going to check some of the dodge forums.

aero_instability

Can you tell if its actually powering on? If so, maybe youre in the mute mode. This is a cool idea as an alternative to the can bus aftermarket harness.

If I read the spec properly, the STB setting is a voltage sense. It looks like if you supply it more than 6.5 volts it will release the mute. The literature also says that a capacitor is used to slow the rise of the supply voltage to prevent popping, so be careful what speakers you test this with.

Let us know what you find.

Woods

On both chips I;

- I grounded pin ADSEL Pin 1 to PGND2 Pin 2, in order to enable legacy mode.

- Then applied power from Vp2 pin 7 (12 volts) to STB Pin 2.

The chips get warm, but there is no sound at the speakers.

aero_instability

Hmm...I know there is fault protection on the amp...is it possible that youre faulting it?

Another idea...are you applying the signal to the chip input pins directly or are you using the input leads (harness pins)? Im wondering if the front-end electronics actually rely on the CAN bus, too. I havent looked at the complete signal path but I know the amp chips are last in the chain, so its possible the amps are ready with no signal...when you turn up the gain on the signal (whatever youre using), do you hear the noise floor getting amplified (ie louder static)? If so, its an input signal problem, if not, its still muted for some reason.

I'd love to see this work because this little amp is actually pretty impressive.

Woods

You've got me still thinking about this.

First off, I'm working directly on the chip and no sound is present, so I'm assuming mute is enabled.

After I shorted the pins, I realized that by default my HU has the output set to zero. I didn't try the amp with the output up and the pins not shorted. So I'll try that next.

I did a bit of research on the aftermarket harness that will enable the factory amp. Here is what it's tied to: Accessory output, Reverse signal, park light signal, Vehicle speed signal and Parking brake outputs.
Given that these are all missing, I wonder it this would be causing the fault.

Here's a link to a good PDF about the harness. LINK

I've contacted the harness manufacturer and am going to see if they would be interested in offering a cheap alternative, that would only enable the amp to work as a standard amp.

aero_instability

I've speculated on how the aftermarket harness works, and I think that it dummys up a volume level...say like the head unit on 25, which effectively sets the amp to a wide-open setting, and then it simply allows you to supply over the speaker outs to act as a variable preamp value. In other words, no real amp level attenuation like the OEM setup, just a throttled input level.

To complicate this more, I believe there are two signal levels out of the head unit: full signal out and off (the -infinity setting).