Stewart Warner Model 91-513 "Spade" Table Radio (1939)
Stewart Warner Spade
The Stewart Warner 91-513 "Spade" is an unusual
and very stylish model from the 1939 season. It
derives its name from the resemblance of its profile to
the "spade" in a deck of playing cards.

It is a 5-tube ac-powered superhet that covers the
standard broadcast band from 540 - 1725kcs. The
tube line-up is:- 6A8G (LO/mixer), 6K7 (IF amp), 6Q7G
(2nd detector/AVC/1st AF), 6K6G (af output), 5W4G
(rectifier). Curiously, all tubes are listed in
Riders as
glass G-types with the exception of the metal type 6K7.
In addition to standard
dial tuning, the set
features four
mechanical
push-buttons for
station selection,
whimsically referred to
by Stewart Warner as
the "magic keyboard".

I purchased this radio
via Ebay in 2006 and
it is both a favorite of
my wife's and mine.
STEWART WARNER MAGIC KEYBOARD IS MYSTERIOUS
Stewart-Warner Automatic Tuner Exclusive
Stewart Warner features the "Magic Keyboard" in presenting its new line of radios. The Magic Keyboard with its "mystic mechanism" is automatic
tuning that operates mechanically rather than electrically, and is an exclusive Stewart Warner feature.

With the Magic Keyboard the radio dialler may have complete and effortless command of as many as 15 different radio stations at his finger tips.
The visible part of Stewart Warner's automatic tuning systems appears on the face of its models as two rows of pushbuttons designed in a fashion
that actually converts into a handsome decoration. A touch on one of these buttons is all that is necessary to bring in the station that it controls.
The tuning is accomplished by the mystic mechanism in the chassis behind the control panel, which goes into immediate action to bring split-second
speed of reception along with positive accuracy of tuning.

The device works silently and entirely automatically and is so flexible the owner of the set may select any 15 different stations he may desire for
selection through the magic keyboard.
Below, is a newspaper cutting from Nov 1937 describing
Stewart Warner's magic keyboard, introduced with their
1938 line and used for several years thereafter.
Although the 1939 Spade has fewer than the 15 push-
buttons referred to, the principle is the same.
Mystic Mechanism with the MAGIC KEYBOARD ...makes even brand new radios out of date.
Copyright TubeRadioLand.com
"An absolutely new idea in cabinets, the first table radio designed for a place in
the middle of the room. Beautifully finished on all sides - and houses a high quality
superheterodyne 5 tube chassis with AVC, tone control, dynamic speaker and 4
station Magic Keyboard tuner"