då kan jag ju svara på mitt eget inlägg då...
Efter att ha läst in mig ordentligt på området och grottat ner mig i en del forum så visar det sig att det behöver lödes pga att jag har en kombo-bracket från asus. Har nu ringt MSI (deras online-support är det värsta jag vart med om). På telefon är det lättare att komunicera även om man hamnar i Holland.
Väntar på att en bracket skall skickas.
De tekniska detaljerna för den som är intresserad eller har samma problem som jag och inte tänker söka runt 1otals timmar.
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Also, depending on the header the SPDIF voltage may be different.
If the original motherboard only has an optical output bracket available, the SPDIF connector on the motherboard is a probably 3.3V or 5V CMOS signal suitable for driving the optical transmitter - if you wire this straight to a coaxial jack you could blow receiving end, sending end or both! And if the mobo only had a coaxial SPDIF output, the SPDIF signal may only be 0.5V-1Vpp, AC-coupled, suitable for driving a coaxial cable but completely unsuitable for driving an optical transmitter.
That "dual-output" bracket you want to use probably has a CMOS signal coming from the motherboard which drives the optical transmitter, along with an AC coupling cap and an attenuator which sets up a suitable output voltage / source impedance for the coax jack. If your motherboard is only set up for driving a coaxial output header, you won't be able to make it work unless you add a bit of extra circuitry inside the header you want to use to boost the SPDIF back up to a CMOS/TTL level.
Bottom line is, if you can get the proper bracket for your motherboard... get it.
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I just tried adapting my ASUS bracket to an MSI motherboard (pulling 5V from elsewhere on the board), and caused the optical out to fail (no more light, even back on the Asus board, though coax out still works on both). It's possible I just zapped it though. I have another bracket to wrec...err, try.
Update: Turns out it didn't work because the ASUS bracket expects to receive the TTL output from the ALC880 chip. The MSI board has a voltage divider on board to reduce the output to S/PDIF standard levels. I managed to get around this by soldering a wire on the input to the voltage divider and wrapping it onto one of the N/C pins and connecting the bracket there. Works now, even if this is a bit of an extreme. I needed optical and I didn't want to deal with an external device. I don't think the other bracket failed from being connected to the low-voltage output, probably I static-shocked it.
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From
http://sound.westhost.com/project85.htm
"TTL Transistor-Transistor Logic - used by nearly all digital logic circuits
TTL is typically (but not always!) 5V (on), and 0V (off). TTL is used as a matter of course within nearly all digital devices, and almost all logic ICs are compatible with these signal levels. TTL S/PDIF outputs are also provided on many sound cards. Many suppliers sell add-on units to accomplish TTL to COAX or TTL to TOSLINK conversion.
COAX Coaxial cable - 75 ohm cable connected with RCA plugs
The coaxial interface uses 75 ohm COAX cable with RCA (phono) connectors. Standard audio interconnect cables will work for transmitting S/PDIF over short distances, but anything over 0.5 metre or so should use 75 ohm cable. The unloaded signal is nominally +/-0.5V and must be terminated with 75 ohms on the receiving end - the resulting signal is +/-0.25V when terminated. Naturally, audio 'speciality' shops love to sell the 'ultimate' cable for up to several hundred dollars, but a cable which you can easily make yourself should cost no more than $10-20 using good quality 75 ohm cable and connectors.
TOSLINK An optical fibre connection
The TOSLINK interface uses optical fibre cables that plug into TOSLINK modules. These modules send or receive a TTL signal. Again, speciality cables will make no difference to the final sound quality, so don't be caught out by the glib sales person who insists that you have to spend serious money to get the best sound. Good quality fibre cables are essential however, as degradation of the optical signal will cause distortion, noise and even loss of signal in extreme cases."
