How to add optical SPDIF out to PC?

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timmmay

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#182490 18-Oct-2015 09:32

I have a headphone amp that has an optical SP/DIF input, as well as RCA, but the optical goes to a decent quality DAC. My other motherboard had an optical out, but the new one doesn't. Can anyone recommend a cheap way to get an SPDIF output into my computer? I only use it occasionally. Presume a PCI card, I'm not a huge fan of USB stuff but if it's cheap I'd do it.

I suspect some sound cards would do it, but it's not worth paying much for this for me.

andrewNZ

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#1408516 18-Oct-2015 10:17

Some PCs have the header ready for it, in which case, you only need the adapter unit that plugs in. Check the motherboard specs

timmmay

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#1408518 18-Oct-2015 10:22

I have a header on the motherboard, but it's electrical and I want optical. I assumed I'd need a card for that.

JaseNZ

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#1408521 18-Oct-2015 10:28

I have got a USB one you can have , I got this a few years ago and never used it. Its yours for the price of the postage if you want it.

In the picture its sitting on an old galaxy s4 to give you an idea of size.

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andrewNZ

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#1408524 18-Oct-2015 10:33

there is a unit that plugs into that header to produce both SPDIF and coax audio. It takes up one case slot at the back.

like this one on amazon

A computer shop gave me one for free.

michaelt

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#1408529 18-Oct-2015 10:46

Yep, it's a very basic photodiode that plugs into the electrical header, converting it to an optical output. That's the easiest way to do it and works fine, however it uses your PC's onboard audio.

If the onboard audio's a Realtek chip, it'll output 5.1 only if it's already encoded (video soundtrack, etc). If it needs to encode it on the fly, it'll only output 2 channel audio, unless you use hacked drivers (which is a real pain under modern versions of Windows, as they aren't signed). If it's only a stereo amp, or you just watch movies then that'll be fine. For surround sound gaming I'd suggest getting a proper PCI or PCI express sound card.

EDIT: I have some spare optical S/PDIF brackets if you want to use the electrical header and can pickup in Auckland.

timmmay

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#1408535 18-Oct-2015 10:50

Presso, thanks for that kind offer. I don't think it's quite what I need right now though.

What I'm trying to do is get unprocessed digital audio information out to the external DAC via optical out so I can plug my headphones in. Does it really get processed if I use that header? Does your bracket have the little circuit that does optical Michael? The headphones, DAC, and amp are all moderately high end - headphones I got free because of my headphones website as review samples but sell for US$1K.

Thanks for the link Andrew, now I know what they're called I can probably find one in NZ, or add to my next Amazon order.

michaelt

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#1408544 18-Oct-2015 11:22

timmmay: Presso, thanks for that kind offer. I don't think it's quite what I need right now though.

What I'm trying to do is get unprocessed digital audio information out to the external DAC via optical out so I can plug my headphones in. Does it really get processed if I use that header? Does your bracket have the little circuit that does optical Michael? The headphones, DAC, and amp are all moderately high end - headphones I got free because of my headphones website as review samples but sell for US$1K.

Thanks for the link Andrew, now I know what they're called I can probably find one in NZ, or add to my next Amazon order.

No, it won't get processed if you use that header, unless it needs to be. If it's already encoded (DD5.1 or DTS or anything similar), it'll just output it as is. The issue is that if it does need to process it, then it can only output uncompressed bitstream audio which is limited to 2 channels on S/PDIF. So it's only an issue if your DAC's not compatible with the encoding, or your computer is generating the audio unencoded (gaming, system sounds, etc). I find it a bit annoying as my HT can handle Dolby Digital and DTS, but not DTS HD. So DTS HD tends to get re-encoded to stereo. You can get around this by using something like reclock, which can re-encode it (using the CPU, not sound card). Introduces a bit of a delay, but you can delay the video as well.

Again, there are Realtek drivers designed for their PCI sound cards that are actually compatible with the onboard audio. They're just a real pain to get running under modern versions of Windows.

I have a bracket with the little circuit, but the circuit's actually not necessary. Most brackets don't have it. The header already outputs at the correct voltage for the photodiode, which is built into the back of the socket. My guess is the reason for the circuit is to handle both the coax and optical outputs on one header.

If you don't need it, I might ask Presso for that USB adaptor. Have an old netbook with no S/PDIF output that I'd like to use for some basic media playback.

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JaseNZ

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#1408546 18-Oct-2015 11:28

This is the full spec for the usb sound box. Its 7.1-Speaker SPDIF Optical Output so not to bad.

http://www.dx.com/p/c-media-cm106-usb-2-0-external-sound-card-box-with-7-1-speaker-spdif-optical-output-15746#.ViLLB2ucw5s

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timmmay

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#1408550 18-Oct-2015 11:34

Oh interesting that the diode works fine from the header. If you can be bothered sending it to Wellington, great, happy to flick up payment of course.

USB thingy looks pretty good, not so much for what I want to do but for Michael. I had something similar a while back, better sound than onboard audio for sure.

michaelt

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#1408559 18-Oct-2015 12:32

timmmay: Oh interesting that the diode works fine from the header. If you can be bothered sending it to Wellington, great, happy to flick up payment of course.

USB thingy looks pretty good, not so much for what I want to do but for Michael. I had something similar a while back, better sound than onboard audio for sure.

Give me a day to find it, but sure, I can send it to you.

timmmay

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#1408560 18-Oct-2015 12:33

Thanks :) Just PM me any costs, I can send you money via bank transfer or paypal.

richms

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#1409378 19-Oct-2015 17:15

I have one of those USB blue box output things that I used on my old PC.

its the only digital output device I have had that manages to add hiss to an optical signal. I have no idea how it happens but there is hiss on that which is not there when I use my basic onboard audio.

Richard rich.ms

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#1409749 20-Oct-2015 11:45

It WILL NOT be unprocessed output btw.

To do that , you need to bypass the Win mixer
You want a USB-DAC device with software that will bypass the Win mixer.
http://www.audialonline.com/articles/kmixer/

"The windows mixer does distort the sound quality by re-sampling the audio stream. So you want to by-pass this mediocre link."
http://blog.musichi.eu/post/2484571391/how-to-set-up-a-pc-to-be-a-hi-fi-transport-for

timmmay

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#1409754 20-Oct-2015 12:02

I guess a USB sound card with SPDIF output is probably a better approach then, thanks :) Any recommendations anyone? Presso, is yours still available?

There's a chance I have one laying around, back from the Windows XP days. If I can find it maybe it'll work on W10...