@papyneau - I inherited *exactly* the same rig from my father (with KEF reference series speakers)
The best first money I spent was on a DAC. Now on a Benchmark DAC3 HGC, it sounds awesome coming through those Mac pieces
You might consider having your pieces refurbished by the folks at Audio Classics in Vestal, NY (Mac specialists) - I did that for the pre & really upped the sound
Over time, the rig became a Mac C2300 (tube pre) and MC152 amp (both purchased from Audio Classics), with Harbeth Super HL5+ speakers
An intermediate step (the 2300 & 152 are about $8k together) could be a used Mac integrated
I will say, the original rig still holds up darn well (I kept my father’s pieces)