EarMic phono connectors - no gnd?

[jesperp]

Hi there

Yesterday i tried to save a small basic program, from my 8300 via MIC connecter/phono-jack cable to a PC soundcard. When SAVE, only noise came into the PC’s recording program.
I discovered that no schield (GND) was connected from mainboard to the phono socket - only signal wire (center pin) was connected from board to socket.

How can it be possible transferring sound, without a reference (GND) connection?

[1024MAK]

Do you mean that the PCB mounted socket has no 0V/GND connection? Or do you mean something different?

Mark

[jesperp]

Do you mean that the PCB mounted socket has no 0V/GND connection? Or do you mean something different?

Mark

“Do you mean that the PCB mounted socket has no 0V/GND connection?”

Excactly, same thing with socket “EAR”.
I will take a picture one of the upcoming days, of both Lambda 8300 and Your Computer.

[jesperp]

Hi All

Disregard this question/issue.
The computer sockets are NOT Phono, but JACK SOCKETS!
I am on the right track again and will return when further testing is done.

[XavSnap]

Hi jesperp,

You should try a MONO JACK socket instead of a STEREO one...

[jesperp]

Hi XavSnap

I am using mono jack plugs into the Lambda 8300, and stereo jack into PC soundcard.

[XavSnap]

Hi jesperp,

As 1024MAK said :"Never use both STEREO channels to like a ZX81 !"
... Or another sound MONO input...

I usually use a "Y" link to couple the both Left/Right channels, but i can't now !


I ever experimented a shortcut on the GND and a sound wire, and the sound was very low.
Just check connector's wiring quality and test the ground/live sound channel resistor. Just in case.

Edit: Tread link to :viewtopic.php?p=47291#p47291