Philco Model 18B (18) Baby Grand Cathedral Radio (1933)
The Philco Model 18 Baby Grand (18B) debuted in July of
1933. It had an initial sales price of $60 and in keeping
with one of Philco's catch-phrases of the day, "
there is a
Philco for every purse and every purpose"
, it was one of no
less than 8 new all-electric Baby Grand models offered for
the 1934 season, ranging in price from $27.50 to $75.
However, perhaps because of Philco's marketing policy,
with the brunt of their Baby Grand advertising focused on
the lower cost Junior models and the top-of-the line
16B, it
was not a big seller and fewer than 13,000 were sold. As
a result, it's relatively uncommon today and has become
highly collectible.

The 18B is an excellent receiver with an impressive
feature list, including:-
        Philco Offers Many Cabinets for Selection

The largest manufacturer of radios in the world has always
offered a variety of cabinets on each chassis they make, but this
year the popularity of its new 16 series has prompted Philco to
offer the option of as many as five different types of cabinets on
the popular series.

In all these models the same 18 chassis is used which means that
four-point bass compensating tone control, shadow tuning and
automatic-volume-control is included, whether the purchaser
selects one of the Inclined Sounding Board models or the more
compact Baby Grand.

The leader in the 18 series, as is invariably the case with Philco, is
the 18X model, in which the patented inclined sounding board,
oversize electrodynamic speaker, and exclusive Philco super "class
A" audio system assure pure and undistorted reproduction of any
program, whether at a whisper or loud enough to fill an auditorium.

Two highboys are also featured in the 18 series-one with doors and
one without. A lowboy of extremely popular design and moderately
priced is the fourth version of the 18 series, while the baby grand
provides the ideal radio for the smaller living room where space is
at a premium.

In addition to covering the complete broadcast band, all of the 18
series will receive police, airplane and amateur communications and
this feature has greatly added to their popularity with radio
listeners who desire more variety to their entertainment than
that provided by the regular broadcasting stations."
...attractive baby grand which offers a score of new improvements.
Like the top-of-the-line model 16B, the 18B features a
Class A output stage using triode connected push-pull
42s and a type 42 driver. Frequency coverage is from
520-1500kc (standard broadcast) and 1.5-4.0mc (short
wave). The 8 tube line-up is 78 (RF), 6A7 (LO & mixer),
78 (IF), 75 (det/AVC/1st AF), 42 (driver), 42*2 (power
amp) and 80 (rectifier). The schematic may be found
here, courtesy of NostalgiaAir.

The model 18 receivers used a new state-of-the-art 8-
tube superheterodyne chassis that was one of the first
Philco designs to adopt the new 6A7 pentagrid conv-
erter tube as mixer and local-oscillator (LO). Prior to
this, to keep the tube count down Philco had no option
but to use the inferior single-tube autodyne circuit in
their economy sets, such as the
51B and even the
19B. This could not accommodate AVC and the
arrangement was unreliable, often ceasing oscillation if
components were slightly out of tolerance. Higher tube
count models avoided these and other issues by using
separate mixer and LO tubes, and many, especially the
all-wave ones, would continue to do so, but the penta-
grid circuit represented a genuine advance, particularly
for the intermediate and junior models. In addition to the
6A7, the 18B also used the new type 78 variable-mu
pentode for RF and IF amplification as well as the
recently introduced 75 for the combined functions of
2nd detector, AVC generation and first AF amplifier.
With the adoption of these multi-function types, Philco
set designers were now able to provide improved audio,
such as super class-A push-pull, and yet still keep the
tube count down and offer the set at an affordable price.

With these 1934 models, all the basic elements of the
economical superheterodyne were now in place and it
can truly be said that the circuit had "come of age".
Tube types would come and go, but the basic config-
uration would now remain intact right through the end of
the tube era.

I found this radio in a large antiques store in Southern
Maine and as I was inspecting it, I saw that it  had two
line cords attached, each with a two-pronged standard
ac-line plug. Upon looking closer, I noticed that one of
these was wired between the antenna and ground. I
feared the worst, feeling certain that someone would
have plugged the incorrect cord in at some time or
another while attempting to try out the radio. This feel-
ing wasn't helped by the assistant in the store asking
me if I wished to do just that! I declined the invitation,
but because of its rarity, I bought the radio anyway.
Upon getting it home and investigating, I discovered that
the antenna coil was
blackened with soot. Yes, some-
one had likely plugged in the incorrect cord! Luckily,
however, though burned, one small accessible piece of
the coil had fused and when repaired the coil showed
the correct resistance and I was able to complete the
  • Super "Class A" Audio System
  • 8-tube superheterodyne circuit
  • Bass Compensating 4-point Tone Control
  • Automatic Volume Control
  • Police and Aeroplane calls
  • Shadowmeter Tuning
  • Beautiful hand-rubbed cabinet of Black
    Walnut and Oriental Wood
The following article was clipped from a newspaper dated March 4th
1934. The reference to model 16 in the first paragraph is curious
and perhaps is a misprint - it would make more sense for it to read
"new 18 series...". The reference to 5 models also appears to over-
look the existence of the model 18RX chaiside with remote speaker.
Philco Model 18B Cathedral Radio Chassis View
Philco 18B Baby Grand Cathedral-Style Radio (1933)
ad clip from Oct. 1933. Click to enlarge.