I have the luxury of two buildings, two systems and only two sources, so I don't need a preamp in my main system. It's both simple, and complicated!
My main, 15 hrs a day music system is digital. I have maybe a thousand CDs ripped to my server in the loft, running LMS and several Squeezebox devices, but the source in the main system is a Raspberry Pi, running PiCorePlayer connected by USB to an Audiolab MDAC modified by the designer John Westlake. This is a USB DAC with digital volume control. This goes via XLR balanced connections to a a box that has a miniDSP balanced unit in it. The analogue full range signal goes to the STA25 then via a passive x-over to the Martin Logan Summit electrostatic panels. The Bass side of things is via the miniDSP unit that corrects some bass resonances and then uses the built in bass section of the Summits to do bass - flat to 20Hz in room with no peaks (some troughs that are difficult to fix). So the Radford only has to be transparent and dynamic from 270Hz upwards - it doesn't find that a challenge.
I've never found a preamp that actually adds anything (how could it?) and when I replaced a Naim NAC82 + 2 x Hcap + NDAC with the stock Audiolab I was absolutely astounded. I'd discovered many years ago that analogue volume controls seem, to me, to have more influence on sound quality than quite a lot of other stuff so when I finally accepted that a digital volume control (within limits) is ok, and actually listened, I realised that maybe less is more. So the STA 25 is basically the only thing between the analogue output of my DAC and the panel. I'm hoping that maybe the next SQ lift will be a better DAC, but maybe we are quite near the top of the tree already - the difference in quality between recordings completely swamps all other factors. Some recordings are sublime, but some are really dire. We mainly listen via Tidal now. Good 16/44 is actually ok, though 24/96 would be nice.
Our analogue system is in a different building - Transcriptors Skeleton/Vestigial Decca London Gold "Naim" boards phono amp with Supercap PSUs, Radford SC22 with custom PSU, Gainclones and Quad ESL57s (and a few other bits).
The intention was to move the STA25 to the vinyl system, but this may not happen. My health situation doesn't support long term plans at the moment, so my main intent at the moment is to leave two useable systems. Rather than optimise them for the long term. My wife is unlikely to use thge vinyl system as much, long term, so I'm working on getting the digital system as good as possible, and properly documented for ongoing use.