C835R tweeter - Videokarma.org TV - Video

kg4cna · #1 06-15-2007, 10:22 PM

Hey guys/girls, I've been searching through the forums and the archive for info on the electrostatic tweeter that my Zenith C835R (as well as several other models) has. When I opened the case, both wires to the tweeter had been cut, leading me to believe the chassis has been removed before. I took some time today and hooked it back up. I had to use the only wire I had on hand at the time, some cheap 24 gauge speaker wire, to make the connections back to their original connection point. When I powered back up, all was fine...but I really can't tell if the tweeter is working. I can cup my hand around it while music is playing but really can't tell any difference. I "think" I can hear it...but I'm just not sure (maybe I'm going deaf). The tone control is set to the midway point. Does this tweeter really make a difference in the already great sound of these radios AND is it obvious if it's working like it should?

Thanks and this place is a great repository of knowledge! I still have alot of reading to do

Allen

Jeffhs · #2 06-16-2007, 02:19 PM

Quote:

Originally Posted by kg4cna

Hey guys/girls, I've been searching through the forums and the archive for info on the electrostatic tweeter that my Zenith C835R (as well as several other models) has. When I opened the case, both wires to the tweeter had been cut, leading me to believe the chassis has been removed before. I took some time today and hooked it back up. I had to use the only wire I had on hand at the time, some cheap 24 gauge speaker wire, to make the connections back to their original connection point. When I powered back up, all was fine...but I really can't tell if the tweeter is working. I can cup my hand around it while music is playing but really can't tell any difference. I "think" I can hear it...but I'm just not sure (maybe I'm going deaf). The tone control is set to the midway point. Does this tweeter really make a difference in the already great sound of these radios AND is it obvious if it's working like it should?

Thanks and this place is a great repository of knowledge! I still have alot of reading to do

Allen

I have a Zenith K-731 with an electrostatic tweeter, and, like yourself, I'm not sure if it is working.

I'm not sure, either, if there is a way to tell whether or not the tweeter is operating as it should. This device is driven directly from the plate of the 35C5 audio output tube, so there should be some output from the tweeter if it isn't damaged or otherwise defective.

I don't know why the former owner of your C835R cut the leads to the electrostat tweeter just to remove the chassis. On the K731, the cable to the tweeter plugs onto a terminal strip on the chassis; all one needs to do to disconnect the tweeter is disconnect the two plugs from the strip. (Most other models of these Zenith radios have a similar arrangement; for instance, in the C845 series, the leads from the tweeter connect to it by means of slip-on connectors.) The only thing I can think of with your 835R is that the tweeter may have, for whatever reason, been hard-wired to the chassis (or perhaps that model's tweeter was hard-wired to begin with), with the leads soldered to the terminal strip I mentioned.

The type of wire used to connect the tweeter shouldn't matter. For connecting a speaker (which is, after all, what the electrostatic tweeter is), speaker wire is just what is needed, although I would think any kind of wire would work just as well.

kg4cna · #3 06-16-2007, 10:11 PM

Quote:

Originally Posted by Jeffhs

I have a Zenith K-731 with an electrostatic tweeter, and, like yourself, I'm not sure if it is working.

I'm not sure, either, if there is a way to tell whether or not the tweeter is operating as it should. This device is driven directly from the plate of the 35C5 audio output tube, so there should be some output from the tweeter if it isn't damaged or otherwise defective.

I don't know why the former owner of your C835R cut the leads to the electrostat tweeter just to remove the chassis. On the K731, the cable to the tweeter plugs onto a terminal strip on the chassis; all one needs to do to disconnect the tweeter is disconnect the two plugs from the strip. (Most other models of these Zenith radios have a similar arrangement; for instance, in the C845 series, the leads from the tweeter connect to it by means of slip-on connectors.) The only thing I can think of with your 835R is that the tweeter may have, for whatever reason, been hard-wired to the chassis (or perhaps that model's tweeter was hard-wired to begin with), with the leads soldered to the terminal strip I mentioned.

The type of wire used to connect the tweeter shouldn't matter. For connecting a speaker (which is, after all, what the electrostatic tweeter is), speaker wire is just what is needed, although I would think any kind of wire would work just as well.

Hey Jeff, thanks for the reply. The old leads were hooked to the terminal strip with slip on connectors...but the connectors had been soldered to the strip. I had to remove the strip and heat 'em up to get them off. Then put new slip on connectors on the ends of the new wire and hooked it back up. I listened again this evening and noticed "some" light high frequency sound coming from it....so it is working...albeit at a low volume. The tone and volume controls don't seem to make much difference. Thanks again! This is a great forum!

By the way, I haven't pulled the chassis on this one yet...so I don't know if any work has already been done on it. Although this radio is playing very well with no hum or other problems, I'll probably recap it (if it hasn't been done already) and replacing the grill cloth. This one has a veneer finish and is in pretty decent shape, it just needs some more cleaning up. Any suggestions on how to clean up a veneer cabinet? What to use? Thanks again!

Nolan Woodbury · #4 06-17-2007, 05:42 PM

Don't expect too much high-end sizzle or volume from that tweeter; it's just a little plastic sandwich. Anyone coming from solid state high-fi equipment may be disappointed in the tonal range of a K-731 or any vintage tube radio. Still, it does add to the experience, and while the K-731 is a wonderful radio it isn't as good as the larger 8 or 12 tube models like the H845 or the MJ 1035.

Even so, many have complained of Zenith's speaker quality, especially concerning the big MJ, but these radios are about smoothness, reception, and quality packaging. With proper care they will still be playing long after most of the modern stuff has been tossed in the dump.

Enjoy them!

Randy Bassham · #5 06-18-2007, 02:40 PM

It must say something that in the final incarnation of these sets, the 845's the tweeter was conventional. My 845's tweeter works just fine, it really brings out the high frequencies especially cymbals when I listen to the local NPR station that plays Jazz in the evenings. These little sets with their output circuits and loudness compensation were light years ahead of other companies offerings of the time, and as Nolan said they were about smoothness, I'd also say pleasing sound. I'm amazed everytime I use my 845 at what the Zenith engineers were able to accomplish with a single 35C5 and about a watt or so output.