A tissue ablation system comprises an ablation source, such as an RF ablation source, configured for generating a common power signal, and a power multiplexor configured for splitting the power signal into first and second power signals, substantially attenuating the second power signal relative to the first power signal to create nominal and attenuated power signals, and sequentially delivering the nominal power signal to each tissue ablation probe, while delivering the attenuated power signal to the remaining ablation probes to which the nominal power signal is currently not delivered.