Premium AAlpine 8.4AN - Succesfully Bypassed Factory Amp

I posted this over at DIYMA but don't seem to be getting much feedback, so thought Inwould post here as well.

As some of you may know fro other threads, I've been having a very tough time getting good SQ out of my 8.4AN system, even with all the upgrades which includes a Bit One DSP.

So I started to learn just enough about Can Bus systems to be dangerous, and learned it is possible to bypass factory amps in these systems as long as you don't mind controlling volume with a DSP.

Well, I started the job, had great success with improved SQ, but still have a few configuration issues.

There are 8 wires coming out of the back of the factory HU that go to the factory amp. They appear to all be digital Speaker signals. They are labelled on Chrysler's wiring diagrams as "Front (Left and Right) Audio", and "Rear (Left and Right) Speaker".

The "Rear Speaker" wires have signal, but the "Front Audio" wires do not.

There is no voltage being sent to the "Front Audio" wires from the back of the factory HU, even When I change the fader to full front.

Of course, when I try to tune the Bit One using the Front Audio wires it gives an error prompt, signal too low.

So I configured it just using the Rear Speaker wires and really had very good results. Much smoother crisper sound than any configuration I tried using the factory amp, and I think it's fair to say I've tried over a hundred different input summing configurations and tunes. The Rear Soeaker outputs from the back of the factory HU appear to have a very good, clean full signal, albeit the voltages are a bit low but that's no surprise.

So here are the issues, the CD player is no longer working even though tje wiring diagrams show it is connected the factory HU and not the factory amp, I lost voice nav and park sense tones (as far as I can tell the wiring diagrams do not show where these are connected in the system).

First priority is SQ, and I feel like I may be leaving something on the table by only using the Rear Speaker wires from the factory HU. Does anyone know why there would be no signal on the Front Audio wires that lead to the factory amp? Perhaps I have a bad factory HU?

Second priority is the CD player, voice nav and park sense times. Any one have any thoughts?

At least it's been confirmed that you can bypass the factory amp on these systems, I don't think I've seen anyone else do this?

Thanks all, this has been quite a learning experience.

And how do you edit the title of a thread? I fat fingered it!

I think the park sense is part of the head unit, whether it's the 3.0, 5.0 or 8.4. When I replaced my 3.0 with a aftermarket unit I lost the park sense sound. Doesn't bother me though.

Sent from my VS985 4G using Tapatalk

This is a thread where someone else tackled the AN HU. Don't know if it will help you but maybe you and the thread starter can create a dialog.

http://www.ramforum.com/f51/2014_ram_1500_qc_diy-like_ca_sql_description-65033/

Personally, after seeing all of the issues due to the Premium Alpine. I think I would LOC every speaker individually into it's own channel of an amp and then send that channel's output back to the original speaker. You would need quite a few amps/channels but if they are already handling the crossovers and such, it might just be the easier and possibly best sounding road to travel. TA could be an issue but with some miniDSP's you'd get some serious control.

I would put money on that the wires that don't have signal on them are the ones that have chimes and cd player on them, but that's just a guess. Can you do a digital signal from an Ipod or other MP3 player to the DSP and bypass the HU all together?

Etroze86 said:

I would put money on that the wires that don't have signal on them are the ones that have chimes and cd player on them, but that's just a guess. Can you do a digital signal from an Ipod or other MP3 player to the DSP and bypass the HU all together?

Click to expand...

Hmmm, interesting. I didn't consider that due to Chysler's naming convention, but that is a possibility.

Will look into that over the weekend. Thanks.

I do have an Aux on the DSP, but I'm not sure what that would tell me. I see no reason why it wouldn't work as it does bypass the HU, but I will try it to confirm.

Thanks for the reminder on that thread Troutspinner. I was subscribed but I don't always get subscription notifications from this site for some reason.

Etroze: Good guess! The Front Audio wires appear to be only for the park sense chimes and voice nav. I never would have come up with that on my own. Thanks.

I got the CD working simply by re plugging the harnesses into the factory amp even though the wiring diagrams do not show the CD player as being connected to the harnesses that lead to the factory amp. So I'm a bit unsure where the CD player is getting its signal from, but I'm not too worried about this as I barely ever use the CD player.

The problem now is figuring out how to connect the Front Audio wires to the Bit One DSP. The Bit One will not configure or accept inputs unless it can calibrate them with white noise. I have no idea how to get inputs that only receive chimes and voice nav to get accepted into the Bit One summing equation.

I'm thinking I will try to calibrate 4 input channels of the Bit One by splitting the left and right rear speaker signals, and then reconnect the Front Audio wires.

What's the worse that can happen? The chimes and voice nav will sound slightly off? I can live with that.

It's amazing how much cleaner the SQ is from the 8.4AN HU after bypassing the factory amp.

RPR let me start an answer here

As far as I have checked and measured the outputs form HU it seems that the signal is sent by the rear outputs and the volume control etc is controlled at the OEM amp by the CanBus.

The trick is that the chime tone from parking sensors is split between each speaker. The NAV is guided to the center one. I have measurements done at the HU outputs when I've noticed they are steady level outputs. I don't want to loose the volume control from the steering wheel.

Anyway in my concept the main audio signal will go to DSP via optilink from DVD & IPod. Basically the HU will only give the poor FM signal and that's all.

I'm sorry but I'm unable to give you more support

Interesting, my center channel has been disconnected since my initial upgrade but I did still get voice nav prompts (before I bypassed the factory amp).

The factory amp does strange things with this signal. Based on how I named my inputs to the Bit One, I got drastically different results with the quality of the voice nav, often extremely muffled.

In any event, the signal upstream of the factory amp is definitely on the Left and Right Front Audio wires, so I just need to figure out how to tie them into my factory amp bypassed solution.

I think my only options are finding a relay (which I am having trouble doing) or a direct connect of the Left and Right Front Audio wires to a discrete speaker somewhere.

However, with only ~1V on these wires off the factory HU, I don't think I can drive a dedicated speaker with this signal.

So a third option is re-running the Left and Right Front Audio wires back to the factory amp and reconnecting the center channel speaker level output from the amp to the center channel speaker. I really don't care about the funky dynamic EQ and poor SQ from the factory amp just for chimes and voice nav.

Little downside to this I suppose, other than the fact that the chimes and voice nav will no longer attenuate the volume of the stereo (music) when they sound.

The third option noted above worked, the Left and Right Front Audio wires from the back of the factory HU were reconnected to the factory amp, and I reconnected the center channel speaker output from the factory amp to the center channel speaker.

Voice nav is now restored to the center channel speaker, which I am now using only for this dedicated purpose.

So the last item is figuring out to restore the park sense chimes, which are routed from the factory amp to each of the 4 door speakers (depending on which sensor is sensing an object).

I cannot direct the chimes to the center speaker, I would effectively have to bridge 5 output channels from the factory amp to one speaker (center, left front door, right front door, left rear door and right rear door).

The only option I really see here (without potentially compromising the clean SQ from the bypassed factory amp solution), is to connect the factory amp outputs for the door speakers to small discrete speakers and hide them under the dash.

This would result in the factory amp being completely bypassed for all music, but it would still be used for voice nav and park sense tones to speakers that I am not using for music playback.

Anybody have other thoughts or recommendations?

Hello! And what was in final result? I have the same issue – there is no factory parking sensors sound through aftermarket amp.

I left it alone. I just use the visual dash warning, no audible alerts.