Works great. Has remote volume, on-off, balance. Single ended only. But two outputs.
Basically this is a Bent Tap-X preamp broken down into 3 modules for flexibility. This is a custom version with slagle formers, not the resistive topology.
You connect the modules via fiber optic cables. The power is only for the display and the control of the volume when activated. So it is passive except for the volume circuit when activated.
I popped one cover to expose the slagle former inside: