There is a Blue Circle BC21.1 pre on Audiogon. Excellent value for the money, and a considerable upgrade from the BC21 - which is a pretty good preamp in it's own right. Mind you, a BC3 Despina at $1500 is an even better deal if you can find one - and there have been a couple...
Need a good used tube pre $1500 or less
The only experience I have had was with an AR LS5mkIII. It is long gone. I no longer need balanced. For the most part I will use it for nothing more than to control volume. Any recommendations including you opinion of the sound characteristics would be welcomed.