Give up on Thiel 3.6 or try another amp again ?

These speakers sound amazing sometimes, especially on small-scale, well recorded material (regardless of genre).

I tried a PS Audio HCA-2 and an Aragon 8002, neither of which sounded particularly good. I'm now driving them with a pair of 90 wpc Quicksilver mono tube amps. I know this is against conventional wisdom, but I like them more than the previous amps as long as I keep the volume moderate.

The problem is that the speakers don't open up and bloom as I turn them up for either large-scale classical or rock music, but rather get hard sounding. It could be the small room overloading, but I suspect it's the amps running out of steam.

Ideally, I would have an unlimited budget to power these speakers with a huge, clean solid state amp. Sadly, I have pretty much no budget at all, so I'd have to sell the Quicksilvers to finance a new amp. This would leave me with $1200 or so for a good, high current, high wattage amp.

I was thinking a used Parasound A21 might fit the bill, but there aren't a whole lot of other options in this price range that seem optimum.

Truthfully, I am starting to think it would more make sense to explore other used speaker options; as nice as the Thiels sound at times, they may simply be too impractical given my financial constraints. Perhaps a pair of Vandersteen 3A signatures or a new pair of 2ce Signature Mk. II? Perhaps the Gallo 3.1s?

What would you do if you were me?

btw, the rest of the system consists of a Quicksilver linestage and a Rega Saturn CD player. Thanks!