A steady and inexpensive color killer circuit system for a simplified video tape recorder of the type wherein the luminance signal and chrominance signal of a color television signal are respectively converted into an angular modulation signal and a lower frequency conversion signal for recording these signals in the form of a combined signal and also where a reproduced lower frequency converted chrominance signal is heterodyned with a continuous signal phase locked to the color burst signal in the reproduced chrominance signal to thereby cancel jitter components in the reproduced chrominance signal. The color killer circuit system comprises a single killer detector provided in the reproducing circuit, said killer detector including a switch for coupling the lower frequency converted chrominance signal on the recording side to the reproducing side circuit, a phase shifter for 90-degree phase shifting either one of two inputs, namely the afore-said color burst signal and a continuous signal, to a phase comparator to produce said continuous signal phase locked to the color burst signal, and a synchronous detector for synchronously detecting the color burst signal with the afore-said continuous signal phase locked thereto. The detection output of the killer detector is used to control the color killer circuits.