Fixed "bus hacking" so chained instruments do not fail when there is no input file.
Fixed "bus hacking" so chained instruments do not fail when there is no input file.

RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix,RTcmix/RTcmix