Help me connect my front panel audio

Nov 2, 2018
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Hi,
So, I have a Biostar a55ml2 motherboard. I also have a really old computer case. I don't know how to connect the front panel audio (mic and headphone) connectors to the actual motherboard, as the manual of the motherboard doesn't match the labels on the connectors. I have attached a photo of what I think I should connect. As you can see, there are two different groups of cable (I think one is for mic and one is for headphones). Please help me figure out where each cable goes, and also the orientation of the cable.
As you can see, on one cable, there is a HPOUT L, HPOUT_L, HPOUT R, GROUND and HPOUT_R. On the other cable there the connectors MIC GND, MIC IN, MIC POWER

(sorry for the bad image quality)
Also, one last thing. I have 8GB ram in my motherboard, and I have two slots. I have another 2GB ddr3 ram (I know that it is compatible with the mobo). When I put it in the other ram slot, the computer turns on but no display. I don't know if the slots are broken, or if the motherboard will only allow two of the same thing.
Thanks
 


Your case probably predates HD Audio standards so I'd assume it will follow AC'97. Using the table on page 14 of your manual for AC'97 try this:

USING HD Audio AC’97
Pin Assignment > YOUR CONNECTIONS
1 Mic In > MIC IN
2 Ground > GROUND
3 Mic Power > MIC POWER
4 Audio Power
5 RT Line Out > HPOUT R
6 RT Line Out > HPOUT_R
7 Reserved
8 Key
9 LFT Line Out > HPOUT L
10 LFT Line Out > HPOUT_L

If you have any small sleeving or can strip some insulation from scrap wire slip it over Pin 4, Audio Power, so that you don't accidentally connect anything to it.

Yes, only one of the two Ground connections are shown attached. You'll have to figure out a way to jumper/splice/whatever the other one on the one ground post. Be creative, but be safe.

If it works but audio sounds indistinct, with weak bass and a vague sensation that your eyes are crossed then you may have reversed the phases on one of channels, so swap the connectors on ONE ONLY of the HPOUT channels.

Pay attention to Note 2. underneath the table.
 
Nov 2, 2018
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I did that, but it doesn't give me the connectors that I have, it has other connectors.
 


Your case probably predates HD Audio standards so I'd assume it will follow AC'97. Using the table on page 14 of your manual for AC'97 try this:

USING HD Audio AC’97
Pin Assignment > YOUR CONNECTIONS
1 Mic In > MIC IN
2 Ground > GROUND
3 Mic Power > MIC POWER
4 Audio Power
5 RT Line Out > HPOUT R
6 RT Line Out > HPOUT_R
7 Reserved
8 Key
9 LFT Line Out > HPOUT L
10 LFT Line Out > HPOUT_L

If you have any small sleeving or can strip some insulation from scrap wire slip it over Pin 4, Audio Power, so that you don't accidentally connect anything to it.

Yes, only one of the two Ground connections are shown attached. You'll have to figure out a way to jumper/splice/whatever the other one on the one ground post. Be creative, but be safe.

If it works but audio sounds indistinct, with weak bass and a vague sensation that your eyes are crossed then you may have reversed the phases on one of channels, so swap the connectors on ONE ONLY of the HPOUT channels.

Pay attention to Note 2. underneath the table.
 
Nov 2, 2018
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Thank you so much. I think that I got ;lucky and I didn't need to do any wire splicing, but for some reason, I can only plug in the headphones part of the way in for them to work.
 


Swap the the connections for both headphone channels to see if it fixes that. that is: swap HPOUT R with HPOUT_R and swap HPOUT L with HPOUT_L.

There's always a bit of trial and error with these things.

Lastly: once you've got it settled in you may be dissatisfied with the sound quality: there may be hissing or buzzing sounds that come and go. Many people just leave the front panel connections off for that reason: the wires running all around the inside of the case pick up electrical noise that is added to the sound you hear. Very distracting with quiet, surreal vocals or soothing violin solos. Probably not for pulse-pounding electro-synth background music accompanying explosions and screams in games. Modern cases have tried to minimize that by using shielded wires both for headphone and mic runs.

If this happens to you the easiest thing to do is simply undo all the hard work and disconnect everything. Instead run a high-quality extension cord... one for mic, one for headphones, shortest that works... from the rear jacks to where you need them OUTSIDE THE CASE and it should improve things. If it's still bothersome, though, that can be chalked up to the nature of low-quality audio codec implementations that lack adequate isolation when crammed onto a motherboard.
 
Nov 2, 2018
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This worked perfectly, and no distortion (except in the mic, but my mic is pretty broken so that is probably why)
Edit: The headphone virtualization also started working, so that is another plus
 

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