How to add digital outs to HU for $6

[SQMaxima]

Figured I would pass on what I have learned about adding a Toslink optic digital output to a HU and yes it really will cost you less then $7. I have done this twice now and it works like a charm. If you have queations or comments please feel free to post them. Sorry for the blurry pics, my cam. such for closeup pictures.

Here you go - My Website

Also, dont anyone know a way to be able to select from more then just two sources using an AI-Net headunit using a 701. Let me know PLEASE.

Rick

[geo1317]

Great find and writeup.

off to digikey to buy some parts and see if i can get this to work for on my 9833.

i got this fron another forum

In europe, the PXA-H701 is identical to pxa-h700. If you have a AINET HU and you connect pxa in AINET mode (not stand alone mode), this is the behaviour:
SOURCE: CD ->pxa chose input through ainet cable N°1 or optical input N°1. If pxa feels optical 1 input, automatically switch from AINET analog signal to optical signal.
SOURCE: CHANGER (only if a AINET changer is connected) ->pxa chose input through ainet cable N°2 or optical input N°2. If pxa feels optical 2 input, automatically switch from AINET analog signal to optical signal.
SOURCE: TUNER ->pxa chose input through ainet cable N°1 or optical input N°3. If pxa feels optical 3 input, automatically switch from AINET analog signal to optical signal.
SOURCE: AUX (you need a HU with AUX mode option)->pxa chose analog input through RCA inputs.
Volume, balance, fader, subw level are all controlled by HU. After installation you can disconnect RUX and use only HU+PXA

IN STAND ALONE MODE instead you choose every input manually and Volume, balance, fader, subw level are all controlled by RUX

[chuyler1]

Wow...I wonder if I could acomplish this with my stock head unit.

I've got a question though, do you only get digital output only when listening to CDs or will the radio signal pass through the digital interface also? Or is that something that depends on the head unit and implimentation?

[chad]

Only with CD.

[geo1317]

Originally Posted by chuyler1

Wow...I wonder if I could acomplish this with my stock head unit.

I've got a question though, do you only get digital output only when listening to CDs or will the radio signal pass through the digital interface also? Or is that something that depends on the head unit and implimentation?

i would think if the head unit has a ADC it would, but most dont, so you only get the CD to play over the digital output.

PS: the parts are on their way from digikey.

[solacedagony]

What exactly are the benefits/disadvantages to using a digital output?

[MarkZ]

Originally Posted by solacedagony

What exactly are the benefits/disadvantages to using a digital output?

Ground loops are often reduced. You bypass the DAC of the HU in favor of an outboard DAC, which some claim provide an audible improvement. You can use external digital processing equipment without the added analog->digital conversion.

Drawbacks are the FM radio thing. Also, optical cables can be fragile, so care must be used when running them through your car.

[chuyler1]

MarkZ hit the nail on the head. I'm actually using an optical connection in my car right now...but I'm not crazy about the look of the aftermarket head unit. I love the red-orange glow of the stock cd player but it's SQ ain't great even after I hacked it open to put RCA outputs on the main board before the amp chip. Perhaps when I get some more funding I'll find a processor that will accept analog and digital inputs and only requires a volume knob to be installed on the dash.

Hey, here's a thought. Could you do the reverse with a digital processor (for example the RF 360 or the AudioControl DQX) to create optical input where there wasn't one originally? That'd be sweet!

[SQMaxima]

If you have a AINET HU and you connect pxa in AINET mode (not stand alone mode), this is the behaviour:
SOURCE: CD ->pxa chose input through ainet cable N°1 or optical input N°1. If pxa feels optical 1 input, automatically switch from AINET analog signal to optical signal.

I sure wish that was true but from what I have found out its not. I have tried it with my modded Alpine with no luck. It will not switch to digital. Now in my girlfriends car she have the Alpine w200 running digital outs to a 701 and once you inable the digital out from the setup menu it works fine. But if you unplug the digital outs it does not switch back to anolog. I am about 95% sure the AI-Net coming from the HU tells the 701 weather our not the unit has a digital out.....in stock form anyways.

Wow...I wonder if I could acomplish this with my stock head unit.

Sure it could. All audio CD and DVD transport have the right signal for the Toslink somewhere in there circuit. Its all a matter of finding it. That would be super stealth to be using a stock HU with digital outs to a nice pro. and equipment. As stated you would still need analog for radio.

Hey, here's a thought. Could you do the reverse with a digital processor (for example the RF 360 or the AudioControl DQX) to create optical input where there wasn't one originally? That'd be sweet!

I am sure you could. The Toslink RX is about as simple as the TX to hook up once you find the right signal path. My queation would be why when you have prossecors like Alpines 701 that has way more options and inout, both digital and analog.

[chuyler1]

Well doesn't the Alpine require a full din unit up front to control the volume? I'm really looking for a solution that will make everything look stock (except maybe a single volume knob that I could integrate into the cigarette lighter or something).

[geo1317]

well no luck finding the DOUT pin or any chip that has a CP-1201 signal. I do have a DSP chip but thats it. anything else i can look for?

http://www.ortodoxism.ro/datasheets2...u93pkkrhky.pdf

here is what the board looks like:

[SQMaxima]

Hmmm. not sure at first glance that is the chip you need. Whats the chip at the top right on the board? The top left looks like a servo driver that controls the motors for spinning the cd plater and the lazer adjustment. Is there anything on the other side of that board?

Let me know, its got to be there somewhere.

Rick

[geo1317]

Originally Posted by SQMaxima

Hmmm. not sure at first glance that is the chip you need. Whats the chip at the top right on the board? The top left looks like a servo driver that controls the motors for spinning the cd plater and the lazer adjustment. Is there anything on the other side of that board?

Let me know, its got to be there somewhere.

Rick

the top right i could not find info on and the the back there is one Panasonic chip and again there was no info on it. i dont have access to the chip numbers at work, I have them at home.

Also i think Alpine can plug into that black socket on the bottom left to test the unit, so there might be a way to get the signal from there. Is there any way i can test for it?

[SQMaxima]

OK, let see if we can work toegether to find the DOUT. If you would can you post the chip numbers/letters. I might have a datasheet for then around here somewhere on my computer. Also be sure to check around on both boards for a point labeled "DOUT". I have seen it both on the transport board and the main board so be sure to check on both.

Once I get the IC numbers hopefully we can find the right point for you.

We will beat this thing, LOL

Rick

[chuyler1]

(threadjack)
I was browsing the rest of your site Rick...Nice job by you and your girlfriend on the Mustang. I saw it at SBN and was very impressed with the attention to detail on the doors. I wouldn't have guessed that it was a one man / one woman job.
(/threadjack)

[geo1317]

Originally Posted by SQMaxima

OK, let see if we can work toegether to find the DOUT. If you would can you post the chip numbers/letters. I might have a datasheet for then around here somewhere on my computer. Also be sure to check around on both boards for a point labeled "DOUT". I have seen it both on the transport board and the main board so be sure to check on both.

Once I get the IC numbers hopefully we can find the right point for you.

We will beat this thing, LOL

Rick

Let see.

This is what i found on the Alpine CDA-9833.

These are all chips on the two boards:

Texas Intrusment
DSP
TMS 160A
320VC5416PGE
CC-39A4LLW

BA5984FP
404 T43

29DL800BA-90PFTN
0352 F76S

AN2200A

PANASONIC
MN---7482WB
(They used a marker and i can read the rest)

M16C
M30626FHPGP
348A1A1

BA6219BFP
351 H47

ALPINE
51T355S2Y03
350C89V

These are marked points on the transport board:
ROUT
LOUT
SGND
NRFDET
ARF
LD

[notacop]

I am wondering if this can work on the Sirius ALP1 tuner. I know the guys at mp3car have an addon board that gives Optical out as well as serial control, I do not need the serial control though. Here is the link to their page: http://www.mp3car.com/store/product_...roducts_id=209

When you add optical outs to a 9835 do mp3 encoded cd's come out the optical or only analog cd's?

Also is there a way to add this to an ipod?


i am planning on getting an alpine h701 and the sources I use currently are:
CD through 9835
MP3 CD through 9835
Sirius Sat Radio through 9835 by way of SIR ALP1 tuner
Ipod throgh 9835 by way of KCA-420i


I am trying to find the best way to still have access to all these sources while using the h701.

[illnastyimpreza]

what are the benefits of using full digital fiber optic cables instead of RCA's??

[chuyler1]

First off, you do not get electromagnetic interference with an optical cable. But the real benefit is not having a D/A converter, followed by a A/D converter, followed by yet another D/A converter. So when you have a processor with optical input, it is best to make use of it.

[hc_TK]

Is it possible to put optical out on my Alpine 9853? It took such a long time to load the How to page, so i didnt read it all..

[crabbdaddy]

Originally Posted by SQMaxima

Figured I would pass on what I have learned about adding a Toslink optic digital output to a HU and yes it really will cost you less then $7. I have done this twice now and it works like a charm. If you have queations or comments please feel free to post them. Sorry for the blurry pics, my cam. such for closeup pictures.

Here you go - My Website

Also, dont anyone know a way to be able to select from more then just two sources using an AI-Net headunit using a 701. Let me know PLEASE.

Rick

great install on the mustang convert on your website!! good info all the way around in this thread.. .cant wait to see the finished product on the mustang.