Hi new guy here with a Zenith Automatic Frequency Control radio

[Jeffhs]

Originally Posted by tomrich22

Nice score on the Zenith radio. I had a K731 that I bought brand new when I was a teen in the 60's. I'll send a pic later. My aunt and uncle had one of those C845 or H845 like Jeffhs. These baby's could pull in the stations with just the cord antenna! I remember listening to my aunt and uncles while baby sitting for my cousins and pulling in stations from Chicago from Grand Rapids MI (thats about 100+ miles away) with just that cord antenna. They don't make um like they use too!

I live in northeastern Ohio near Lake Erie and close to Cleveland, Erie, Pennsylvania and Youngstown, Ohio. When the conditions are right, I can receive stations on my C845 from Erie and Youngstown (and Cleveland, of course), simply using the line cord as an antenna, just as well as if they were local. Being so close to the lake (within one mile), I often hear stations from southwestern Ontario, Canada on my C845 in the summer as well. I bet it's the 6BJ6 RF stage and the two-stage (three if you count the limiter stage--this radio does not use the standard FM ratio detector) IF strip that does it. Zenith's engineers obviously designed the C845 and its variants for DX reception and great sound. I bet a lot of these radios were sold in weak-signal areas.

I have a K731 as well that is every bit as sensitive as my C845. In addition to the FM RF stage, this radio also uses, like the '845, a limiter stage ahead of the second IF amp, which amounts to three IF stages. The sound is pleasing and better than most table radios of that era (early 1960s), but not as good as the C845, due to a 5x7 oval speaker and an electrostatic tweeter driven directly from the plate of the audio output tube (35C5). I think my K731 is a little too bassy, even with the tone control set close to midrange. With the control set fully CCW (counterclockwise), the bass is so strong that I'm actually afraid the speaker may be damaged. On the other hand, the tone control on my C845 does not overemphasize the bass range, even with the control set fully CCW. (I usually set it at midrange and leave it there.) I'd be interested to know why there is (or should be) such a difference in tone control action between these radios. The only thing I can come up with right now is that one or more caps in the tone compensation circuits of the K731 may be leaky or may have drifted in value (if such is possible with capacitors as it is with resistors). Haven't recapped either set yet.

[chasaboo]

I still haven't replaced any parts on this Zenith and it really does sound magical. The music from it is just stunning. I mostly listen to classical music and some blues.

I'd be nervous to replace anything for fear of ruining the good sound it does have. I'm keeping an eye out for another one in case this one does blow up.

Thanks for all the great advice and info you've given me in this thread. Really great stuff.

Zenith, the quality goes in before the name goes on.