I still own two of the Big Preamps and more recently had Arek make a custom Khozmo dual-mono passive using his best Amtrans AMRG resistors and volume control from the Hattor, upgraded connectors, and only a single input and output (i.e., no switching) that I use to remote control the volume and provide a display into my solid state, unity-gain buffer.
The Big Preamp is IMO hard to beat for the money and for what you get wrt the volume control, remote, display, balance, connectivity (RCA and XLR), flexibility (i.e., passive vs. active with variable/switchable gain), and of course sound quality. I also owned the Hattor Tube Active Stage, which is quite nice as an option to their op-amp active stage (my Hattor preamps have the NewClassD op-amps).
Do you have specific questions?