S-Video to Composite

A basic S-Video to composite convertor can be made by a simple short of the two signal wires, and the two ground wires of the S-Video. Looking AT an S-Video plug (IE with pins) with the rectangular notch of plastic at the bottom, pin 4 is the pin at the top right, pin 3 is the top left, pin 2 is the bottom right, pin 1 is the bottom left.

In the simple bodge the results are useuable if absolutely necessary, but gives poor colour quality, and a ghosted image.

Pin 4 and 3 are connected straight to the signal pin of composite. Pin 2 and 1 are connected straight to the ground pin of composite.

In the better, but more complicated, version a capacitor is used. The value of this capacitor can be anywhere between 400pF and 10nF according to the web link : http://www.epanorama.net/circuits/svideo2cvideo.html. One bought from Farnell used 420pF, Ystv has lots with 470pF capacitors.

In the complicated version pin 4 (the crominance) is NOT connected straight to the composite signal pin. Pin 4 is connected to the capacitor, the other terminal of the capacitor is connected to the composite pin.

Pin 3 (the luminance) is connected straight to the composite signal pin. If a physically small capacitor is used then it can just about be contained within the plug case, this is of course a more durable method than having it exposed.

As with the simple bodge, the complicated bodge has pins 1 and 2 connected straight to the compostie ground.

Notes are that this will supposedly take an S-Video signal and convert it to a PAL or NTSC compatible composite signal. 75 ohm shielded cable should be used, failing that it should be shielded audio cable.