Philco Model 21 Baby Grand (Late) Cathedral Radio (1931)
The 7-tube Philco model 21 made its debut in the early spring
of 1931, in a stylish new cabinet designed by
Edward Combs.
In its
early form, it used the same chassis as the model 20 that
it superseded, using two 71A triodes for power amplification.
However, shortly after its introduction it received an upgraded
chassis, featuring, among other improvements, two of the newer
more efficient type 45 power tubes in place of the 71As. An ad
from May 4th 1931 announcing arrival of upgraded sets at a
dealership can be seen in the thumbnail below left. Notice that
the illustration incorrectly depicts the curvy front arch of the
model 20
deluxe rather than of the model 21 as finally realized!

The reign of the model 21 was short, for in June Philco intro-
duced their 1931/32 line-up, without a model 21. Instead, for
socket-power sets, they debuted models
70 and 90, followed
shortly thereafter by the model
50, all in a similar cab to the
discontinued model 21. The 50 was very short lived in this
cabinet, as it almost immediately received
new styling; until
recently it was uncertain if any were actually produced. Models
70 and 90 however would go on to be huge sellers for Philco.
Meanwhile, with model 21 available for sale only during the
off-season months of March, April and May, not many were
sold, making it the rarest of the 21, 70 and 90 trio today.
Philco model 21 baby Grand (late version) 1931.
click to enlarge
A new Philco Masterpiece. Philco Model 21. The radio sensation of the year.
newspaper ad, May 4th 1931
For more information on the Philco model 21, including the
schematics, see the model 21 Tech page at