Adding Optical output to an Alpine CDA-9813

There are very few cd players on the market with optical (Toslink) outputs, and even fewer single din Alpine AI-Net players with optical outputs.
The inspiration for this modification came from where a different Alpine deck is modified, I recommend reading that tutorial as well unless you are specifically looking for information about an Alpine CDA-9813.

I’m not going to get into the basic steps of opening the cd player or removing the transport, if you are not comfortable doing those steps by yourself this modification probably isn’t for you. 

A Toslink transmitter is a very simple device with typically 3 connections, Data In, V+, Gnd.  All photo’s and references apply to part #425-2701-ND as used in this modification.  Three connections need to be located on the board/cd transport to connect this device, +5V dc, Ground, and DOUT.  Alpine was kind enough to label the DOUT pin/trace on the cd transport and this was followed to the main board so that all connections are made on the main PCB instead of the CD transport.

Click on image to view full size.

I used 28awg wire for all connections, but any small awg wire you have on hand should be suitable.  Larger wire may be difficult to solder to the very small pins/pads on this PCB, be very careful not to make solder bridges to adjacent pins or pads.  Leave all of the wires long enough to safely route to the back of the cd player where you will be mounting the Toslink transmitter, a little extra length doesn’t hurt and wires can be trimmed to length later. 

Once the three wires are soldered to the respective pins and routed to the Toslink transmitter, use a non conductive adhesive to secure and provide strain relief to the wires.  I used hot glue that I tested to be non conductive and applied it over the solder joints and along the wires every few inches.  Keep these wires away from the cd transport as well as the motorized tilt mechanism of the faceplate.

Click on image to view full size.

To reduce clutter behind the deck I removed the front/rear/subwoofer RCA pre-outs from the cd player by unplugging the connections from the main board as shown above circled in black.  All speaker output wires were heatshrinked and zip tied out of the way to keep them safe and compact.

If I were to do this modification again I would probably mount the Toslink transmitter where the RCA pre-outs exit the chassis to retain the cooling fan.  This could be done by enlarging the vertical slot that the RCA bundle slides into then adding a hole below the slot for the mounting screw of the transmitter.  Remove the cooling fan at your own risk!!!
Below you can see the Toslink transmitter mounted where the cooling fan was removed.  You can also see the vertical slot that could be widened to allow the Transmitter to be mounted there while retaining the cooling fan.

Click on image to view full size.

The total cost of the modification was $1.18US because I already had the wire/hot glue/heatshrink on hand, and was placing an order with Digikey for other items.   The ~45deg angle that the transmitter is mounted does not affect performance and as you can see below when an optical cable is connected everything connects and looks just fine.

Click on image to view full size.

Now that everything is complete it’s time to test it, I used the optical output and fed it into an EMU 0404 USBs optical input.  It worked first try on the bench and was left running for 48 hours mostly covered to simulate the limited airflow inside a vehicles dash.  The unit gets warm but not hot, and should work just fine for years.

Click on image to view full size.


2 Responses to “Adding Optical output to an Alpine CDA-9813”

  1. […] Re: Which Alpine HU to get for the H701… possibly, but it's really a simple process especially on the older alpines. I'm not 100% sure about the new ones though, I haven't had one apart. I have more info here that outlines the steps a little better for others to follow. Adding Optical output to an Alpine CDA-9813 Robin Wainwright's Blog […]

  2. Hi, i have an alpine 7892 and am having trouble finding the digital signal
    the board is a bit different from your player, you have a tip for me
    help you find? if so we can exchange information by email

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