Splitting Video Output

[toledoflyer]

Raising this from the dead. Some good input on this thread. I actually been working on a JAMMA Dongle for this. The design is currently utilizing opamps but honestly reviewing this i may be able to get away with just a few transistors and greatly lower the cost.

You might want to stay with the op amp design. The issue with emitter followers in a circuit like this is the output voltage is shifted down by the EB forward voltage (.6 to .7V). This means without a negative supply voltage for the emitter resistor video level below .6 will be cutoff to 0. In other words dim colors may be distorted in color or disappear completely (be black)

One way to solve this is use a PNP transistor with a pull up to +12V followed by a diode to drop the shifted voltage back down to where it was on the input.