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Would it be possible to create an Optical Out?

post #1 of 41
7/25/07 at 12:33pm
Thread Starter 
As per the topic, am I wondering if it would be possible to do something like bypass the DAC in, for instance, an X5, and create an optical out? Has anyone ever done something like that before? I tried searching, but no luck.
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post #2 of 41
7/25/07 at 12:41pm
I don't think this is possible ...
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post #3 of 41
7/25/07 at 12:44pm
Thread Starter 
Damn, that sucks. I would love to hook up my X5 to an external DAC.
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post #4 of 41
7/25/07 at 12:47pm
There is a Iriver H1XX on the FS forum. Buy it and sell your X5 ...
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post #5 of 41
7/25/07 at 1:31pm
Quote:
Originally Posted by epaludo View Post
I don't think this is possible ...
Anything is possible, it just may not be practical or worth the effort.
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post #6 of 41
7/25/07 at 1:51pm
By that point of view, of course it's possible. But he definitely wants a viable solution and not an dream one ...
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post #7 of 41
7/25/07 at 2:05pm
Thread Starter 
Why is it so not worth it? I don't really have much knowledge about cables and etc.
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post #8 of 41
7/25/07 at 3:48pm
It's pretty easy...

For the optical transmitter, Toshiba TOTX177 part number 1225771 from Farnell will do the trick assuming the piece of kit you're on about is 5V. Try the TOTX147 if it's 3.3V.

You need to find the SPDIF signal inside the X5 (if there is one) to send to this transmitter. Then the only other connections it needs are +5V and ground with a decent capacitor between them.

If there is no SPDIF inside the X5 (I have no idea) you will need an SPDIF transceiver. Try the Wolfson WM8804, it will convert the I2S or 16b RJ data or whatever it is into SPDIF and you can then fire it at the optical transmitter and the job's a good un.

Edit: Just dawned on me that the X5 is perhaps a portable device and that's why people have said it will be tricky, if it is, I agree!
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post #9 of 41
7/25/07 at 3:55pm
right. if you have s/pdif, converting to optical is a walk in the park. But why bother?
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post #10 of 41
8/8/07 at 7:26pm
Thread Starter 
http://www.rockbox.org/twiki/bin/vie...dio_Codec_with
http://focus.ti.com/docs/prod/folder...320aic23b.html

I'm guessing that's the DAC? Does that mean it has S/PDIF or no?
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post #11 of 41
8/8/07 at 9:56pm
Just read the datasheet, and you'll know
It states that there is a digital out (pin DOUT), in the I2S format. Jambo has already described all the steps necessary.
And Jambo, I don't think it's that tricky. You just need to route 3 wires outside the case: LRCOUT (the clock), DOUT (data) and DGND (ground). then just as you described
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post #12 of 41
8/8/07 at 11:03pm
Thread Starter 
Do I need the Wolfson transceiver? I don't really know the lingo, connections, and whatnot, but I love to learn.

Edit: Oh, I forgot to ask, would it be possible to still have signal going to the DAC and the line out? My end goal, if this is possible, is to create a transportable rig including a good external DAC (Headroom's MicroDAC?) and transportable amp (LISA III?) and cans, and also a portable rig, which would be line out to an amp (Tomahawk) and IEM's (UE11's? current Shures?) possibly doing something like the iMod (ie. using a high quality cable inside from the DAC to the LO, using a cap inside like the 4g iMod or making my own LOD with a cap built in like the 5g iMod...but that would probably be much more work than I'm up to).
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post #13 of 41
8/8/07 at 11:49pm
Yes, or a similar chip. You just need some kind of converter. You have an I2S signal, which is for internal use only. It must be converted to SPDIF, and then converted to optical (which is basically SPDIF, only optical). Does it need to be an optical out? Just an SPDIF out would be a bit easier to implement, and optical doesn't really give any improvement.
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post #14 of 41
8/9/07 at 12:30am
Thread Starter 
Well, I'm not really looking specifically for optical out, but digital, so I can run it to an external DAC. So would S/PDIF out be like coaxial, RCA, or what? And could I even fit it in the X5? (I guess I should crack it open and take some pictures...)

Edit: To be clearer, my end goal is to somehow have a digital out that I can use with an external DAC, probably the Micro DAC from Headroom. What parts do I need? How do I do it? Etc.

As I said, I'm a noob, but I'm willing to learn.
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post #15 of 41
8/9/07 at 10:21am
Quote:
Originally Posted by balou View Post
Just read the datasheet, and you'll know
It states that there is a digital out (pin DOUT), in the I2S format. Jambo has already described all the steps necessary.
And Jambo, I don't think it's that tricky. You just need to route 3 wires outside the case: LRCOUT (the clock), DOUT (data) and DGND (ground). then just as you described
interesting. now, I'm a newb at this stuff too, but there are four unused pins on the connection running into the subpack (9, 12, 17, and 20), and this part is the 22-pin connector that can be used to make line-in, out, usb, etc. so might there be a way to run from the digital outs on the codec/amp through the subpack connector, and then build the rest into the dac itself? of course, using the part linked above rather than the subpack.
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