Maybe Leaving SET for Solid State because I want bass

To @dhcod, many of us here have or use to run SET amps (tube, and SS type SET transistor design amps) and understand why you might be looking for a little more punch and drive. 

While this can be a tradeoff with lower power SET amps and amps with lower damping factor, imo it does not necessarily mean you have to replace your amp. It all depends on your speakers of course, however there are other approaches.  

It was suggested earlier to add a subwoofer, and using it for the lower end support, speed, and adding a small 7" or 9" REL type sub can work too.  I've run dual subs with my former set amps and current higher power PushPull / Utlralinear amps, and its only for the extra low-end drive and reinforcement you'd like to add, and particularly so on some recordings. The nice part is you can adjust it up/down, adding what you need, just enough.  Best of Luck.  

@decooney, I agree with your recommendation.  I use a pair of JL Audio subs with my 45, 2a3 and 300b amps in the past and didn’t miss a beat.  I typically favor sealed enclosures and felt the JL’s had the speed and bass tightness to open up the soundstage and give me all the lower bass I needed.

I wouldn’t go to solid state... I’d go to a higher wattage tube amp. I’d look at a CJ or ARC, VAC. 

However, slam... the brick wall chest thumping bass is something different. It is the somewhat unnatural lean midrange or upper bass and huge surge of current. Kind of the mark of solid state. While exhilarating... I have never experienced it in the real world. A good tube amp will give you full and articulate bass, Maybe that is what you want. 

Thanks everyone. These are all good point. I'm going to try the Atma-Sphere D amps. They are small enough to rotate in when I'm in the mood. In any case it will be a good experiment.

Another option is to consider a tube preamp and SS amp. When I had my speaker setup that is where I found my sweet spot. I had an  LTA pre and  a GaN amp.