The Wonderful Zenith K731

[Paula]

The Wonderful Zenith K731

The first picture below is of a Zenith model K731 radio that I acquired several months ago. It is an AM/FM receiver with seven tubes, a luxurious walnut veneer cabinet (with solid walnut trim), a large speaker, and a seperate electrostatic tweeter.

With the K731, Zenith had reached the pinnacle of performance for a mass-produced, American-made, tube-type table radio. The handwriting was already on the wall for tube audio, and the economics of high-volume, injection-molded plastic cabinetry had all-but-rendered the solid wood cabinet financially impractical for mass-produced radios.

I've always loved this particular radio, as it is the exact same model that my dad gave to my mom for Christmas around 1965. These radios are still fairly common and easy to find. The one I found was in very good shape, requiring only minor work to make it perfect. Besides a good cleaning, inside and out, I made some repairs to the grille cloth, revived the finish by giving it "The Formby's Treatment", replaced all of the paper capacitors, replaced the selenium rectifier with a silicone rectifier, and added a 1/2 amp in-line fuse.

The second picture below shows the end result of the electrical restoration. Notice that the original filter cap was left intact, and that the new electrolytics, as well as the silicone rectifier were securely attached to solder-lug strips. The nifty powder-blue, 2-watt resistor replaces the original "dropping resistor" to compensate for the lower voltage drop of the new rectifier.

The Zenith now looks and works like new, with unbelievable tuning sensitivity and selectivity on both AM and FM. I listen to this radio for hours on end, and it never wanders off the station. With the large speaker, separate tweeter, and hefty wooden cabinet, the sound is rich and full.

The K731 came in two cabinet styles: the more modern style with legs, like mine, and an Early-American style, shown in the third picture. I think that I actually prefer the looks of the Early-American style, but it does not have the same sentimental value as mine.

Paula