LS5 MkI

About the LS5 MkI

The Audio Research Corporation LS5 MkI, introduced in 1993, is the initial version of the renowned LS5 series of fully balanced tube line-stage preamplifiers. It set the foundation for subsequent MkII and MkIII models with significant redesigns. Known for its transparency, rich tube sound, and excellent three-dimensional imaging, the LS5 MkI uses vacuum tube audio circuits with a solid-state power supply. It requires an optional BL2 input controller ( ) for single-ended (RCA) inputs as it primarily supports balanced XLR connections. The MkI version features a more populated PCB compared to the redesigned MkII, which moved to open-loop circuits and different tube complement. Original It is highly regarded by audiophiles for its musicality, though the MkII addressed some microphony issues with 12BH7 tubes by switching to 6922 types.