718 Ch= Series X

Beginning in 1940, Howard released it's top line of models - with the number 718, the year after the top model Symphonic with 16 tubes was released. Before, howard made also 19 tube receivers like Deluxe (ca. 1933) and Grand (ca. 1938). See also our "SchematicFinder".

The family for 12 tubes with chassis "series X"
The models have the following bands: BC (540 - 1700 kHz); TROP (1800 - 5000 kHz) and SW (5.5 - 18.0 MHz) bands. BC band has six push-button station selectors. The 718 series X has also a tuning eye and a push-pull audio amplifier. The 12 tube-chassis series X has 4 knobs in one row.

Beitman covers the 718 series X as model 718X - see volume 5, page 59 of 1942.
Rider's perpetual schematic is in volume 12 (copyrighted 1941), Howard 12-19 as model 718. The chassis has a consumption of 105 watts and the changer of 30 watts. Voice coil 8 ohms, field 900 ohms (drop of -100 volts). The Rider schematic is from 10-1-1940 (October, drawing number C84-715). The 6SF6 are Audio Amp and Bass Amp and the 6J5GT is the inverter.

Known models
For the 12 tube chassis (4 knobs in line) we know at least models 718 (Beitman names 718X) and 718APC. Stein "Pre-War Consoles" (page 98) names the 718APC for 1942 and with FM, maybe it was still sold in 1942, but we believe that the 12 tube chassis was for AM only. Slusser "Antique Radios", 7th ed. page 140 shows it correctly with 12 tubes for 1940 (walnut, inner right front slide rule dial, inner left phono, doors, front grille with vertical bars, 4 knobs (no pushbuttons?). He puts the model 718C console to 1941, walnut, upper front rectangular dial, lower vertical grille bars, 6 pushbuttons, 4 knobs, 12 tubes.

The family for 14 tubes with chassis 718-FM or 718-FM series X.
The main difference between those very similar chassis are the trimmers, 718-FM has 21 trimmers, 718-FM series X has 24 trimmers - according Rider 13-12, drawing C91-715.
The models have the same bands as 718 series X plus FM around 48 mc. They are 14 tube, 4 band, RF stage, loop antenna for broadcast band, mechanical Push-Button Tuning with declutching system, built-in phono switch, bass boost, treble control, beam power output, inverse feed-back, 6 ohm coice coil, power consumption 115 watts, AC only. The chassis has 5 knobs (2 + 3).

Rider's perpetual schematic is in volume 13 (copyrighted 1942), Howard 13-11 to 13-15. Last page for 718FM series  X.

Rider's perpetual, volume 14, Howard 14-5 and 14-6 (copyrighted 1944) informs only about the new model 200 record changer with two changer blades for the model 718-X radio phono combination.

Known models
718FM and/or 718FMX, 718FMC and 718XFMA (Stein) or it is 718FMA. They are Chippendale models. Slusser (same book and page) writes for 718-FM: console, 1941, wood, upper front side rule dial, lower cloth grille with vertical bars, pushbuttons, 4 knobs, BC, SW, 14 tubes, AC ...

The post WW2 families with chassis FM-718 and 718-FM-5-6
Rider's perpetual covers the model FM-718 (note, FM is in front!) in volume 17, page Howard 17-20 to 17-22 - has 15 tubes.  The models use two tubes 7H7 as first and second IF instead of the 6SK7 and have a third 7H7 as 3rd IF (for FM), the limiter is a 7C7, discriminator 6SQ7, 1st AF and bass 7C7. In short, it has one tube more as a limiter and different tubes - compared with the 718-FM-5-6 with 14 tubes.
The 718-FM-5-6 is shown on pages 17-23 to 17-28. It has also 24 trimmers like the series X. A special power transformer for 117, 135 and 230 volts 40 to 60 cycles is available. At least Chippendale cabinets "A" type or "C" type (718-FMC post WW2) were available. Tubes not identical to pre war: 6SJ7 instead of 6SF5 for 1st AF Amp and Bass. Only 4 controls are listed! Is that correct?

Ernst Erb, 15.Mar.11

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