I own the Spatial Audio M4 Triode Masters. These are the smaller version of your speakers. I started with a Cary Rocket 88R tube amp that was good for 60 watts in ultralinear mode. I tried EL34 and KT88 tubes but the bass just disappeared when music was played. I listen to mostly jazz at normal levels so it's not like I was asking for a lot of bass. The amp was a good one but I don't think the tubes played well with the open baffle speakers.
I then moved on to a solid state CODA 10.5R amplifier (100 watts with first 25 watts in Class A) teamed up with an LTA mz3 preamp. This combination is very good and provides all the bass the speakers can put out. The LTA MZ3 was so good I decided to try LTA's ZOTL10 amplifier. Even though the ZOTL 10 is only 10 watts, it drives the speakers as well (if not better) than the CODA amp. Even though the ZOTL is a tube amplifier, the low end frequency response is more like a solid state amp.
Given your budget, the LTA amp and preamp are going to be way over what you want to spend. For your budget, I would recommend a used quality solid state amplifier like the CODA ( I purchased it used for $1,200.00) and a new or used tube preamplifier.
I then moved on to a solid state CODA 10.5R amplifier (100 watts with first 25 watts in Class A) teamed up with an LTA mz3 preamp. This combination is very good and provides all the bass the speakers can put out. The LTA MZ3 was so good I decided to try LTA's ZOTL10 amplifier. Even though the ZOTL 10 is only 10 watts, it drives the speakers as well (if not better) than the CODA amp. Even though the ZOTL is a tube amplifier, the low end frequency response is more like a solid state amp.
Given your budget, the LTA amp and preamp are going to be way over what you want to spend. For your budget, I would recommend a used quality solid state amplifier like the CODA ( I purchased it used for $1,200.00) and a new or used tube preamplifier.