Hi new guy here with a Zenith Automatic Frequency Control radio

[Seafarer12]

I also agree with updating components. It would be a shame to loose a good old radio because of component failure. When I went through my H845. I replaced the selenium diode with a silicon diode. I also replaced the electolytic and wax caps. Cleaned all the pots and replaced all the tubes. All my tubes were original and were weak. The thing is great. It sounds better than my Pioneer SX-780. It is on my work bench up at the plant and I get all kinds of compliments on it. I have only gotten a couple gigs about being an I&E tech with a tube radio. Oh well.

[chasaboo]

Thanks lads for the great info and advice.

I still haven't gotten around to cracking the Zenith open yet but I've been playing it a few times now and it sounds pretty good. I'm sure it could sound better though.

One of these days I'll pop him open and hopefully take some pictures in the process.

[Sandy G]

If you ever run acrost a Zenith MJ-1035, GRAB IT !! That's an order... (grin)..Seriously, its their TOTL table set from c. 1965, has 11-12 tubes, & should have an outboard speaker for stereo w/it. They sound great, & are pretty good at picking up distant stations, both AM & FM...You WON'T be sorry if you get one !

[chasaboo]

I'm feeling much better actually.

Well I finally opened up the Zenith. I was going to make a list of the tubes and see if there were any leaking caps and such. I got the chassis out of the plastic bucket with no trouble. I counted 7 tubes 3 of which were zenith which looked quite old and 4 of which were Sylvania which are rather new. Kind of a bummer because the markings stating the type of tube are quite faint and unreadable. Hmmm.

I tried to get the bottom plate off to scope out the capacitors but the way the thing is setup I can't get my driver on the last two bolts. Hmmm.

Well I was then checking out the speaker when I noticed something jammed in between the basket and the cone. It was an 8" long, 1/2" inch wide strip of black velvet. They use it all around the face plate to make a nice seal when it's all closed up. Apparently when the last person was in the radio they pushed the face plate on and the velvet wound up jammed against the back of the cone. This was clearly causing some of my bad sound problem.

I freed the velvet and glued it to the top of the faceplate where it belongs. I bundled it all up and gave him another try. Wow! What a difference. It's funny because before the tone control had almost no effect at all. Now the sound is much more open and I can flatten it out or lower it with the tone control. Very happy!

This is one nice radio after all. Some day I'll figure out what tubes are in this thing and replace them all as well as the caps, for now it sure does sound nice.

Thanks for all the advice lads. I'll be back with this radio one day with some more questions.

[Tom Bavis]

Sounds like a C725 that I have. Does it look like this one?

[chasaboo]

That's it exactly dude except that the plastic bucket part on mine is a pale green. How do you feel about the sound that your Zenith produces Tom?

He's not a bad radio and if you let it warm up long enough he sounds pretty nice. I've been using him as an early morning radio and light night working radio.

I was going to spring for an old sony table top radio but since I freed up the speaker I'm happy with this guy for the time being with his tubes.

[tomrich22]

Hey Chasaboo, The sound is great from my Zenith. It is a two way system. There is like a small tweeter on the left hand side. Sounds pretty good.

[chasaboo]

Wow, I can't recall seeing a tweeter. I'll have to open him up again and see.

I'm pretty sure all I had was the one oval speaker.

It sounds pretty good since I straightened it out.

[tomrich22]

yea there is an oval speaker and a small little tweeter on right side( not the left as previously stated). It adds some highs when you turn up the treble.

[anden]

Repeating what others have said.....these 7 and 8 tube Zenith's with AFC produced from 1955-67 were so nice. What make them enjoyable is, they were a medium sized unit at about 15 inches wide & about 10 lbs. but they performed like a bigger radio. Zenith quality was A1 !

They stop me in my tracks when ever I see one at a radio swap, flea market or yard sale...if priced right, I end up bringing it home. The collection is starting to get out of hand - the family includes..Y832, H835, C835, C845, H845,C730,C735, K731 and about 20 of the smaller Zenith's from the 50s & 60s. Recently I've become interested in the top shelf solid state AM/FM models from 1968-71 with the acoustic suspension loudspeaker & wood cabinets. Yes, they are transistorized, but are very nice radio's with impressive audio, and as it turns out, were among the last of the Chicago made Zeniths ! (these can be found for very low prices still....$5., $10.)

Time to get another bookshelf for all these !

[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.