Classic Hifi Care

I've never seen a discussion of the advantages of the Radionic cartridge system Zenith used. It's in my Wurlitzer jukebox. I can think of some advantages. It's a system that modulates an RF signal via the moving stylus then demodulates it. I would imagine that this would allow a lower-mass stylus that would respond better to high frequencies, and that it would permit higher compliance because the stylus does not have to flex anything to generate a signal, for less stylus and groove wear. It's much like a magnetic cartridge system in those regards. That may be why it was chosen for jukebox use--extended stylus and record life.

But maybe there were other considerations? Like just being different for advertising purposes?

Does anybody know?

Chris Campbell

I seem to remember a discussion sometime ago about Radionic cartridges but that may have been on the old Vintage forum.

Bill

A few years back, a Zenith HF1284 from 1957 was in the shop, small chassis added with a 6J5 for use with a Radionic Cart.
I did not try to restore the cobra matic, it needed too much work and customer wanted radio and amplifier mostly.

A friend bought an old Zenith mono record player with a radio and using a Radionic cartridge at an auction. He brought it to me to "make it work again without spending any money". It needed a cartridge, since the needle was broken. Even it being a Zenith, which never work for me, it built out nice and he uses the thing to play records on. He is into bluegrass, and says he plays stereo records on it with no issues. He thinks it is the best thing since sliced bread. I find that a bit difficult to believe, but whatever.....

The Zenith Radionic Cobra cartridge was great when it came out in the late 1940s. It had good compliance and relatively low record wear. Zenith dropped the cartridge in the mid-1950s and the later ceramic Cobra cartridges have better frequency response for hi-fi.

Wurlitzer used the Radionic cartridge right through their last mono jukeboxes in 1962. Wurlitzer used a more complex oscillator circut than Zenith had used and actually got good hi-fi sound from the Radionic cartridge in their jukeboxes.

Ken Doyle wrote: ↑Sat Jan 11, 2025 2:34 pm The Zenith Radionic Cobra cartridge was great when it came out in the late 1940s. It had good compliance and relatively low record wear. Zenith dropped the cartridge in the mid-1950s and the later ceramic Cobra cartridges have better frequency response for hi-fi.

Wurlitzer used the Radionic cartridge right through their last mono jukeboxes in 1962. Wurlitzer used a more complex oscillator circut than Zenith had used and actually got good hi-fi sound from the Radionic cartridge in their jukeboxes.

Those were the advantages I expected. The reduced record wear would have been a plus for jukebox service. My '48 Wurlitzer 1100 doesn't have extended high frequency response but that may be built into later amp stages.

Chris Campbell