@OP
I would offer this….
what is it about the present sound you wish to change? improve: delete?
BAT offers some fine fully balanced gear.
depending on budget, there are an immense number of options out there, Nagra, VAC, VTL, CJ, Atmas, etc.
I’d try to figure out what I wanted most and then figure on how deep into those waters I’d want to wade.
that said, Change just for the sake of change ain’t a bad idea either. now and then.
I love the idea of a tube line stage, or preamp. just because it allows me to alter the sound from time to time merely by rolling some glass.
tube type might be for some, a big consideration too. 6DJ8’s? 12AT’s? Russian 33s? 6SN7s? then too there’s NOS or brand & ERA. which is why I tend to cling to the first two families I mentioned here.
the one tip I’d suggest there is when you find a setup you enjoy via tubes being used, get out there and at least buy a complete secondary set of them!
Glass, like nearly everything else on this rock, ain’t forever.!
best of luck!