What @Spanngitter wrote. The single preamp tube in the first generation Valvestates are not used in the clean channel circuit, only the distortion channel. This changed in the second generation Valvestates. The fact that your clean channel is healthy but the dirt channel is problematic calls for a new12AX7. Also hit the preamp tube pins with contact cleaner and work it in/out of the socket a few times to remove any oxidation.