AC-171-600 Boston audio signal cable SH-940 Shadow violin pick-up system SH-941 Shadow violin pick-up system SH-SV-1 Shadow violin pick-up system SH-SV-2 Shadow violin pick-up system SH-945-NFX Shadow Nanoflex violin pick-up system FWF-MV2 FWF violin and viola omnidirectional microphone + double piezo with preamp and volume control FWF-MV1 FWF violin and viola passive double piezo pickup with low pass filter