This is a Grebe Synchrophase, a later AC version called the AC-6 (1928). It's in very nice condition, and has the table/base with built-in speaker.
http://www.radiomuseum.org/r/grebe_s...phase_ac6.html
You usually see the earlier MU-1 version with six dials, which seems to sell for $225 on average in good condition. I don't know if the scarcity of this model makes it any more valuable or not.
This Grebe page has a pic of one with the speaker table, about halfway down the page.
http://www.greberadio.com/