OHMs are not tube friendly, so if a tube amp is a must, you can get by perhaps, but are not likely to max out performance with any OHM Walshes I suspect.
500 w/ch IcePower is the bomb however with both my OHM Walshes, 5S3 and 100S3. The Dyns and Triangle work fine with the IcePower but the differences with those from prior amps (Carver m4.0t and Musical Fidelity A3CR) is not as significant.
I've also owned B&W P6s and Magnepan mg1c's, and original OHM Walsh 2s in recent years prior to my current setup. The B&Ws were nice in larger rooms but never imaged the way I liked. The Maggies were fantastic for years in the large basement room of my old town home but never clicked in my new house. The Triangle Titus' with sub was the best combo I had with these speaks in house at the time. That was a top notch combo running off a Tandberg tr2080 receiver in my second rig. The original OHM Walsh 2s were nice but not nearly as refined top to bottom as the newer designs (they were over 25 years old though). I traded those in towards the OHM F5s. OHm has a very nice trade-in policy where you can receive up to 40% off new speaker cost by trading in up to two pair of older OHMs that I took advantage of to obtain the F5s at a very favorable price compared to new Walsh 5S3s.