The best preamplifiers I found that worked well with all the early Meridian Active loudspeakers and were a real stepup from the 101B were all from the Burmester range of around the same vintage. I did home trial very many others including Audio Research SP8, SP9, SP10, Perreaux (can’t remember which model), but this one was good as well. A bit better than the Burmester 785.
The Burmester pre’s I tried were the 785 (a popular choice for M2’s and M10’s then), 846 and separate matching phono stage (better). I ended up though with an early Burmester 808 that was way better than anything else. I got it a a very good price, but it was still much more than my Meridian M10 Speakers. I still have it though and I am using it now with my Dutch & Dutch 8c’s so has been a very good investment and been totally reliable all this time.
There was a Burmester 785 on sale here a few months back at £400 that may not have sold?:
https://pinkfishmedia.net/forum/threads/burmester-785-preamp-with-phono-mm-mc.255008/