sound

  • Thread starter Thread starter Sam
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Sam

hi
can anybody help,got no sound from the spdif output on the board but from
the optical.
K8N-E DELUXE
BIOS,1007.007
SANDRASAM
 
"Sam" said:
hi
can anybody help,got no sound from the spdif output on the board but from
the optical.
K8N-E DELUXE
BIOS,1007.007
SANDRASAM
Click to expand...

The K8N-E uses the Realtek ALC850.

The Realtek datasheet is in this ZIP file.
ftp://210.51.181.211/pc/ac97/alc850/alc850_data3.zip

The Realtek reference schematic is in this ZIP file.
ftp://202.65.194.18/pc/ac97/alc850/alc850_a64.zip

Page 4 of ALC_AC97_COLAY_VER_064.pdf from the a64.zip
file, shows that the SPDIF copper connector and the
SPDIF optical module (TOTX178 in the diagram), are
driven from a common signal. If the output of the
optical module is working, then the copper output should
work at the same time.

The Realtek datasheet for the chip, shows that the SPDIF
output driver has a 3.3V signal on it, and it can drive a
75 ohm load to ground. This sounds like a very powerful
driver. The Realtek circuit uses a couple of resistors, to
attenuate the signal a bit, and match the line impedance.

You should be using 75 ohm coaxial cable, to connect the
motherboard to the receiver. The coax cable should have
RCA jacks on the ends, or adapters of some sort, to get
connected to the coax.

I thought the signal level of SPDIF was pretty low -

Cable: 75ohm +/-5% (l<10m) or 75ohm +/-35% (l>10m)
* Line driver:
* Zout: 75ohm +/-20% (100kHz .. 6Mhz)
* Vout: 0.4Vpp .. 0.6Vpp, <0.05Vdc (75ohm terminated)
* Line receiver:
* Zin: 75ohm +/-5%
* Vin: 0.2Vpp .. 0.6Vpp

I wonder if the Realtek circuit just has too high an
amplitude ? By my calculation, the Realtek circuit
will develop a 1Vpp signal at the receiver, which is
not quite the same as the little blurb I copied above.

I don't know of an easy way to prove there is any signal
at all on the coax connector. Due to the simplicity of the
Realtek reference circuit, it is highly unlikely the
motherboard is defective. I say this, because you have
got an optical signal from the motherboard, and if it is
working, there are precious few components between that
(proven) point in the circuit, and the RCA copper output
jack. So, maybe your receiver just doesn't like the signal.
Does the lock indicator make any indication when connected
to the copper connector ?

If you have a long piece of coax cable handy, try using
a longer cable. A long cable should attenuate the signal
somewhat.

Paul
 
hi paul
thanks for your advice i think its defective myself as you say,well the....
spdif.... in the volume control panel.(win xp) is greyed out.
i have reformated a new drive to see if its anything i have put on my pc to
stop it working,well the drive just has win xp on and the asus driver
software the came with the board,and its just the same as when i have my
other drive on,anyway i have phoned the place ware i got it from and thay
want me to bring it in to look at it so do you think i should take the box
and all the bits with me aswell

yours Samantha
 
"Sam" said:
hi paul
thanks for your advice i think its defective myself as you say,well the....
spdif.... in the volume control panel.(win xp) is greyed out.
i have reformated a new drive to see if its anything i have put on my pc to
stop it working,well the drive just has win xp on and the asus driver
software the came with the board,and its just the same as when i have my
other drive on,anyway i have phoned the place ware i got it from and thay
want me to bring it in to look at it so do you think i should take the box
and all the bits with me aswell

yours Samantha
Click to expand...

A search in Google suggests the "wave control" sets the volume
for SPDIF, and maybe that is the reason it is greyed out. I don't
have an SPDIF receiver to test that.

Paul
 
hi
well got the mobo changed but do you know its the same as the other one
,where did you find the thing about wave control.
sam
 
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