I’m not sure what the difference is between a “Micro” tube and a “Micro DS” tube, but apparently it was a big difference, and the Micro DS was much better, as shown by the illustration above, which appeared on the cover of the May 1928 issue of the Soviet magazine Радио Всем (Radio Vsem, Radio All) magazine.  The smaller illustration at the left was inside the magazine, and made clear that the DS had the upper hand.

The issue contained two receivers using the Micro DS tube, including the two-tube reflex set shown here.

The issue also carried detailed plans for constructing the variable tuning coil shown below: