I have never owned Special 25's, but I did own 3.3's which are similar, and found that VAC's Renaissance 140/140 Mk. III's had a particular synergy with them, sounding much better than Rowland Model 6's run from batteries or a Bryston 4B-ST. For whatever reason, the VAC amps really made the 3.3's sing in my systems.
My guess is that the Renaissance 70/70 Mk. III, which is much more powerful than its 65 watt/channel rating would indicate (they have outstanding output transformers and power supplies, and can drive 2 Ohm loads), would work really well with the Special 25's. They are going for as little as $4k used now, and are particularly trouble-free as tube amps go because of their auto-biasing, tube-failure protection circuit and long-life 300-B output tubes.
Good luck.
My guess is that the Renaissance 70/70 Mk. III, which is much more powerful than its 65 watt/channel rating would indicate (they have outstanding output transformers and power supplies, and can drive 2 Ohm loads), would work really well with the Special 25's. They are going for as little as $4k used now, and are particularly trouble-free as tube amps go because of their auto-biasing, tube-failure protection circuit and long-life 300-B output tubes.
Good luck.