Which used preamp for Halo A21, under $1,000?

There are plenty of balanced tube preamps, but do you actually need one? Tubes have larger distortions noise and higher output impedance. Balanced solid state preamplification is prefered IMHO.

I don't necessarily need a balanced tube pre, but I'd like to consider all of my options.

New possibility: Has anyone heard the Coda CLX pre? From what I gather, it's a Window IV with upgraded parts.

The CLX is a Coda CL with upgraded parts. The CL is a slight improvement over the Windows Continuum 4. I own a CL, it is the highest value pre that I have sat in front of. This is a bold Statement, but I would have no problem putting the CLX in the league of a Pass X10. Very high performance for the $$$. It really depends on your taste, but certainly worth a listen, but....How do you get a CLX for $1000?

I wish I could get one for $1,000, but it will actually be closer to $1800. I'm willing to go that high if the performance is there. But since I'm now thinking in that range, the other pre that seems comparable is the Wyrrd4Sound STP-SE. Thoughts on how they compare?