The RK-003 is a little kit we made to mix your gear in the simplest way possible. The mixer can be used for audio but also for e.g. the splitting of sync signals.
Note: This is a ‘passive mixer’ which means there is no amplifier in it, only small resistors to protect the gear you’re mixing. You have to adjust volume on the devices itself and expect a volume drop which needs to be compensated on the amplifier on which your mixing to.
PCB + Parts, simple DIY assembly (+soldering) required
Info from Retrokits