For the past decade or so, I haven't been using a preamplifier. The D/A processors I have been using all have volume controls, so I have been feeding their outputs directly to the power amplifiers. It would seem logical that having nothing in the signal path would have less of a degrading effect than a preamp's input and output sockets, switches, volume control, printed circuit-board traces, and active and passive parts, not to mention an additional pair of interconnects. However, with some of the preamplifiers I have auditioned in my system, there was no doubt that the sound quality improved compared with the direct connection from the digital processor.
The most recent of these preamps was the MBL N11 that Jason Victor Serinus reviewed in
July 2021, which was preceded by the Pass Labs XP-32 I reviewed in
March 2021, the Benchmark LA4 Kalman Rubinson reviewed in
January 2020, and going back even further, the Ayre Acoustics KX-R Twenty I reviewed in
December 2014, which was one of the products Ayre released to celebrate its 20th year of operation.
I am now reviewing the KX-8 line preamplifier, which costs $6500 in basic form.