No info about availability.
Mic Preamplifier
Hand selected 100% discrete electronics Hammond broadcast transformer output AccuState™ low-noise input circuit 3-position Vox control for added air or punch
http://www.radialeng.com/powerpre.php
These merchants probably sell this module. Huh?
Included in 20 Racks, 5 are public:
Radial PowerPre 500 Series Mic Preamp
Radial PowerPre 500 Series Mic Preamp
Radial PowerPre 500 Series Mic Preamp
Radial PowerPre
Radial PowerPre 500 Series Mic Preamp
Radial PowerPre 500 Mic Preamplifier