My friend is using the Krell KBL preamp on his Mcintosh MC 500 amp. The Krell is from the early 90s. Its really well built and has a natural sound to it. It has a separate power supply. Other good preamps I'v heard that I liked,
Pass P preamp, Adcom 750 modified by Stan Warren, Threshold T2, T3, and YBA 2 preamplifier which has 2 volume controls.
Pass P preamp, Adcom 750 modified by Stan Warren, Threshold T2, T3, and YBA 2 preamplifier which has 2 volume controls.