Note
QST, Aug 1955 p. 103. "Coming next month"
QST, Sep 1955, p. 87. With specs.
Has an optional tilt-base power supply similar to the RAP-250-S, but without speakers. Seen in this photo: QST Apr 1956, p. 97.
Date of introduction of the MB-560-A is unclear. Morrow's advertising for all of 1956 never refers to the 560-A. But a QST review in November 1956 means the "A" version must have been released a couple of month earlier, probably September. The difference between the 560 and the 560-A appears to be greater TVI protection.
Mobile use requires the optional RVP-250 vibrator power supply.
Review (MB-560A): QST, Nov 1956, page 40.
Review (MB-560): CQ, Nov 1956, page 52.