Gigabyte MA78GM-S2H questions

Been years since I had a gigabyte board, but very impressed with this one.
Using it in a HTPC, which it is ideal for.
Q1 Front panel audio header. My case
http://www.coolermaster.com/products...=636&id=4 195
seems to have AC-97 front panel audio (although Coolermaster state HD audio,
the leaflet with the case says AC-97). I disabled the front panel jack
detection, as it did not work, and the sound now works fine from the front
panel. But oddly it comes out from the back motherboard audio jack at the
same time. The manual says that when using AC-97, you can only have front or
back, not both, and that is what I wanted - the sound cutting off when you
plug in headphones. As it is, I have to manually turn down the sound on my
TV each time I want to use headphones. which is a bit of a pain. Either the
manual is wrong or my case wiring is unusual? I wondered how it works for
other users...
Q2 The Gigabyte SB700 heatsink on the board gets very hot in use. None of
the software supplied seems to give me the temperature, just the usual CPU,
system and hard drive temps. Should I be worried about the heat of this
part?

GTS wrote:
Been years since I had a gigabyte board, but very impressed with this one.
Using it in a HTPC, which it is ideal for.
Q1 Front panel audio header. My case
http://www.coolermaster.com/products...=636&id=4 195
seems to have AC-97 front panel audio (although Coolermaster state HD audio,
the leaflet with the case says AC-97). I disabled the front panel jack
detection, as it did not work, and the sound now works fine from the front
panel. But oddly it comes out from the back motherboard audio jack at the
same time. The manual says that when using AC-97, you can only have front or
back, not both, and that is what I wanted - the sound cutting off when you
plug in headphones. As it is, I have to manually turn down the sound on my
TV each time I want to use headphones. which is a bit of a pain. Either the
manual is wrong or my case wiring is unusual? I wondered how it works for
other users...
Q2 The Gigabyte SB700 heatsink on the board gets very hot in use. None of
the software supplied seems to give me the temperature, just the usual CPU,
system and hard drive temps. Should I be worried about the heat of this
part?


On the original AC'97, rear speaker muting is implemented via
the way things are wired. The 2x5 F_AUDIO header in those
days, had stereo headphone output signals, but also had two return
signals. By means of switches inside the headphone jack on
the computer case, plugging in front headphones, interrupted
the return signal flow, which caused the rear speakers to be
muted. It meant there was a relationship between the
headphones in the front, and the speakers in the back.
If you didn't have F_AUDIO wiring connected, two jumpers were
put in place on the 2x5 header, to maintain signal continuity,
so the rear green jack would work.

With HD_Audio, things are different. Firstly, there are enough
outputs on an HDAudio CODEC, that front headphones and rear
speakers have separate ports. When muting is desired, it is
implemented in the driver software.

HD_Audio has two plug detection methods. One method is based
on switches inside each jack. When you plug in a 1/8" plug,
the switch is activated, and via the wiring to the CODEC,
the CODEC knows there is a state change underway.

Most computer cases, lack the special jacks with the switch
inside them. As a result, a second fallback method is used.
Many CODECs have impedance sensing, were (presumably) a measurement
is done on a regular basis, looking for current flow. Based on that
measurement method, the driver and control panel know when
something has been plugged in. (The measurement method is
not documented, so remains a mystery. Presumably someone has
a patent on it.)

Now, in theory, it should be easy, when headphones are plugged in,
to mute the rear green jack. The problem is the complexity of the
RealTek control panels, and figuring out what you need to do
to get that behavior. RealTek supports multistreaming, meaning
you can send separate audio content to front panel and rear speakers.
And you don't want that. I think it is also possible to support
more than one set of headphones at a time, via the chip (each port
can have the headphone amp enabled on it). There is plenty of
functionality there, but looking at this page, I cannot see a
specific tick box that does "old style" muting in software.

http://h10025.www1.hp.com/ewfrf/wc/f...me=c00 377375

I wish RealTek would write a manual like that, to make it all
easier to figure out.

Paul

http://h10025.www1.hp.com/ewfrf/wc/f...me=c00 377375

I wish RealTek would write a manual like that, to make it all
easier to figure out.

Thank you for excellent info.
Having read through the guide you linked to, I am confident my Realtek audio
is setup correctly for AC97 audio - I don't have multi-streaming enabled,
and turning on front panel jack detection simply means that I loose audio
from the front, as it never detects the headphones being plugged in. Looking
again at the motherboard manual, it states that pin 10 and pin 6 are not
connected. But my case FP audio connector has pin 10 as L RET and six as R
RET. If these act like the old jumpers you used to get on the motherboard,
then I guess that is one explanation why the sound is coming from front and
back at the same time. Odd though if the mobo manual says 6 & 10 are not
connected...
I could try disconnecting 6 & 10 from the front panel audio plug, but what I
don't want is a situation like my last case, as if you plugged in the front
audio connector on that one, the rear output was permanently cut off - the
only way to get the rear output working was to disconnect the FP header. On
that case, the problem was that there was no L RET or R RET wires. The HD
audio panel is confusing - I'm now not even sure if it is meant to detect
headphones in AC97 mode or not!

GTS wrote:
http://h10025.www1.hp.com/ewfrf/wc/f...me=c00 377375

I wish RealTek would write a manual like that, to make it all
easier to figure out.

Thank you for excellent info.
Having read through the guide you linked to, I am confident my Realtek audio
is setup correctly for AC97 audio - I don't have multi-streaming enabled,
and turning on front panel jack detection simply means that I loose audio
from the front, as it never detects the headphones being plugged in. Looking
again at the motherboard manual, it states that pin 10 and pin 6 are not
connected. But my case FP audio connector has pin 10 as L RET and six as R
RET. If these act like the old jumpers you used to get on the motherboard,
then I guess that is one explanation why the sound is coming from front and
back at the same time. Odd though if the mobo manual says 6 & 10 are not
connected...
I could try disconnecting 6 & 10 from the front panel audio plug, but what I
don't want is a situation like my last case, as if you plugged in the front
audio connector on that one, the rear output was permanently cut off - the
only way to get the rear output working was to disconnect the FP header. On
that case, the problem was that there was no L RET or R RET wires. The HD
audio panel is confusing - I'm now not even sure if it is meant to detect
headphones in AC97 mode or not!



In principle, you shouldn't connect L_RET and R_RET, because if you do,
they go to the jack detection wiring. That means the audio gets wired
to the jack detection resistor tree, placing a small DC connection on the
front headphone jack. So start by disconnecting them, if possible. I
don't think that will affect anything in a positive way, but they
aren't needed, and neither should jumper plugs be needed if
the audio header is not being used. Since HDaudio has separate ports,
there is no reason to "return" the front audio signals to anything.

In general, for all the AC'97 computer cases out there, and HDaudio
equipped motherboards, only five wires are required. Two for
headphone contacts tip and ring, two for microphone contacts
tip and ring, and a common ground for both. Since an AC'97 computer
case doesn't support jack sense via separate side switches, there
are no other useful wires to connect up.

Once you've done that, go back and play with the jack detection setting,
and see if any behaviors have changed.

Paul

I wouldnt worry to much on the Southbridge chip. I've had mine running hot
for about a year now, and it runs fine. You can do a bit of modding and
maybe put some Compound to reduce the heat, and there are SB fans etc you
can get for very cheap. It shouldnt really matter that much though.

"GTS" wrote in message
...
Been years since I had a gigabyte board, but very impressed with this one.
Using it in a HTPC, which it is ideal for.
Q1 Front panel audio header. My case
http://www.coolermaster.com/products...=636&id=4 195
seems to have AC-97 front panel audio (although Coolermaster state HD
audio, the leaflet with the case says AC-97). I disabled the front panel
jack detection, as it did not work, and the sound now works fine from the
front panel. But oddly it comes out from the back motherboard audio jack
at the same time. The manual says that when using AC-97, you can only have
front or back, not both, and that is what I wanted - the sound cutting off
when you plug in headphones. As it is, I have to manually turn down the
sound on my TV each time I want to use headphones. which is a bit of a
pain. Either the manual is wrong or my case wiring is unusual? I wondered
how it works for other users...
Q2 The Gigabyte SB700 heatsink on the board gets very hot in use. None of
the software supplied seems to give me the temperature, just the usual
CPU, system and hard drive temps. Should I be worried about the heat of
this part?