Vintage EICO HF-85 vacuum tube preamplifier/preamp with original manual

Old mid-century vintage, Eico model HF-85  vacuum tube stereophonic preamplifier, complete with the original manual. The manual has about 40 pages, including parts lists, schematics, diagrams and drawings. There is also a loose larger-then-life assembly It has some pen and pencil marks. It measures about 12" x 9" x 4".

This stereo preamplifier is fresh out of an estate and is nice and clean. We don't know much about this, but we were told that it is a 20 watt amp.  We plugged it in and the tubes glow, but we're selling this for restoration or parts.