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 Post subject: What was the last year Zenith used the Cobra tone arm?
PostPosted: Jan Mon 19, 2009 3:59 am 
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I have always liked Zeniths Cobra-matic series of players,besides being very light weight for their time,the arm was very oddly styled and looked like a futuristic snake complete with eyes.
I have a portable from around 1956 that has the Cobra tone arm but the changer is made by V-M.
What was the last year Zenith made the Cobra arm changers?
Was there ever a stereo cobra?
Also,if memory serves me correctly I recall seeing a variation of the Corba arm without the eyes..did the eyes creep people out or something?


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 Post subject:
PostPosted: Jan Mon 19, 2009 4:43 am 
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Yes, there was a later stereo cobra changer. It was just a Zenith branded VM built changer with the cobra tonearm. The cartridge was a regular old ElectroVoice ceramic. I think they switched from the cobra arm to the microtouch 2G arm somewhere around '61.


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 Post subject:
PostPosted: Jan Mon 19, 2009 4:48 am 
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I'm not sure of the exact year that Zenith started using VM to build their Cobra changers. I think it was around '56, before stereo in '58.

However.... they continued to build their own deluxe cobra changer that had a 45 spindle that split and folded down into the turntable platter. Like the VM models, the cobra arm on this Zenith built model was used in the first stereo units then later used the Micro-touch 2G tone arm.

This version disappeared after VM started building Cobras
Image

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 Post subject:
PostPosted: Jan Mon 19, 2009 6:20 am 
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Nice stroboscopic Cobra changer! thats actually my favorite Cobra model! I love the "stroboscopic" script. and the flowing design of the case.
I used to have a danish modern console with the Micro-touch 2g tonearm,it had a clear cartridge that floated inside a white headshell and there was a button you could depress to rotate the stylus from microgroove to 78.

I know the Cobra was also used in the Wurlitzer 1100 jukebox.
In the early ads when the Cobra appeared it showed a Cobra arm with lighting bolts traveling down the length of the arm and said "Out of this world...music played via radionic wave".
I have always wondered what they meant,was the pickup wireless and it somehow transmitted signal to the preamp?


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 Post subject:
PostPosted: Jan Mon 19, 2009 6:47 am 
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radiotvnut wrote:
Yes, there was a later stereo cobra changer. It was just a Zenith branded VM built changer with the cobra tonearm. The cartridge was a regular old ElectroVoice ceramic. I think they switched from the cobra arm to the microtouch 2G arm somewhere around '61.


Thanks for the info,I have never seen a stereo cobra sure would be neat to find a portable!


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 Post subject:
PostPosted: Jan Mon 19, 2009 1:09 pm 
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The Cobra above has a low voltage electronic cycle trip solenoid. the reject button is a switch and the trip at the end of the record is an electrical contact point.

Hi-Fi in Fiberglass wrote:
...music played via radionic wave".
I have always wondered what they meant,was the pickup wireless and it somehow transmitted signal to the preamp?

The original Cobra cartridge used a moving vane technique to generate the audio signal. It was more of a variable capacitance cartridge that varied a radio frequency oscillator. The oscillator signal was detected much like an AM radio signal and converted to audio.

When hi-fi became the buzzword in the mid '50s, Zenith dropped the original cobra moving vane cartridges for ceramic.

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 Post subject:
PostPosted: Jan Tue 20, 2009 2:20 am 
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I believe the last use of the cobra shaped arm was in
1962 on Zeniths custom built "Stereo Professional"
belt drive record changer that doug mentioned.
This changer was only used in the top of the line
units and was supossedly the first belt driven changer.
This changer was in use in their top models until 1969.
This changer is an outstanding performer.
I recently converted my top of the line 1967 Y960
consoles Micro-Touch arm to use a small Ortofon
magnetic cartridge and i was able to put this cartridge in the Zenith hinged floating bracket to keep the original look. It tracks perfectly at 1.5 grams. This is less than the original two grams for the original cartridge, but the arm is friction free
due to it riding on jeweled bearings (Zenith really got this right) so it works at the lower force with no problems and beacuse the changer is belt driven,
there is no rumble or noise.
Of course i did have to add a preamp for the cartridge.


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 Post subject:
PostPosted: Jan Tue 20, 2009 5:56 am 
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orthophonic wrote:
I believe the last use of the cobra shaped arm was in
1962 on Zeniths custom built "Stereo Professional"
belt drive record changer that doug mentioned.
This changer was only used in the top of the line
units and was supossedly the first belt driven changer.
This changer was in use in their top models until 1969.
This changer is an outstanding performer.
I recently converted my top of the line 1967 Y960
consoles Micro-Touch arm to use a small Ortofon
magnetic cartridge and i was able to put this cartridge in the Zenith hinged floating bracket to keep the original look. It tracks perfectly at 1.5 grams. This is less than the original two grams for the original cartridge, but the arm is friction free
due to it riding on jeweled bearings (Zenith really got this right) so it works at the lower force with no problems and beacuse the changer is belt driven,
there is no rumble or noise.
Of course i did have to add a preamp for the cartridge.




Hi Orthophonic!
I have never seen a belt drive Cobra turntable,would it be possible to post a photo?
Thanks!


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 Post subject:
PostPosted: Jan Wed 21, 2009 4:02 am 
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Location: Winter Park, Florida
I don't have a digital camera yet but hope to get one soon to post a picture.


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 Post subject:
PostPosted: Jan Wed 21, 2009 4:17 am 
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If this is of any interest ? The Wurlitzer jukebox company used the Zenith cobra cartridge & circuit in some of their jukeboxes . My model 1250 has it .


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 Post subject:
PostPosted: Jan Wed 21, 2009 5:13 pm 
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Hey Ken, to add to it, Wurlitzer used the green cobra up to the end of their mono machines. The late 104 selection models after stereo appeared still used the green cobras up to about 1961. They were not common as most came as stereo. I owned a 2304 from 1959 and have worked on 2404 and 2504 which still were using the green Zenith cobra cartridge. All the 100 and 200 selection versions of the 2300 to 2500 I have seen were stereo with Sonotone cartridges.

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 Post subject:
PostPosted: Jan Thu 22, 2009 11:39 am 
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Fred Rice wrote:
Hey Ken, to add to it, Wurlitzer used the green cobra up to the end of their mono machines. The late 104 selection models after stereo appeared still used the green cobras up to about 1961. They were not common as most came as stereo. I owned a 2304 from 1959 and have worked on 2404 and 2504 which still were using the green Zenith cobra cartridge. All the 100 and 200 selection versions of the 2300 to 2500 I have seen were stereo with Sonotone cartridges.


I had no idea Wurlitzer used the Cobra arm that late!
A friend has a 2300 but its the stereo version so it doesnt have the Cobra and I have a 2510 that is mono as it just says "high Fidelity on the dome,but it doesnt have the Cobra either.
It has the gold arm with sonotone cart.
Its a great looking box though and has Jetsons styling with gold hourglasses that float on poles in front of the speaker screen.

Speaking of the Cobra,is the "power point" type of cartridge they used on the early Zenith Cobras as well as Motorola Calypso harmful to records?


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 Post subject:
PostPosted: Jan Thu 22, 2009 1:15 pm 
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Hi-Fi in Fiberglass wrote:
... Speaking of the Cobra,is the "power point" type of cartridge they used on the early Zenith Cobras as well as Motorola Calypso harmful to records?


Don't confuse a Cobra plug in cartridge with a Power Point. They were different. The early moving vane Cobra cartridges were state of the art. The later ceramic version was not as good but it was still better than some of the competition.

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 Post subject:
PostPosted: Jan Thu 22, 2009 4:12 pm 
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Doug brought up a good point. The original Cobra pickups (Radionic types) like the green, red/green and red cartridges were perhaps the earliest and only ones that don't generate a voltage. All the later ones with a ceramic element generate voltage when used. The earlier ones control the output of an external oscillator tube.


Hi-fi in fiberglass,
Speaking on the cobra jukeboxes again, I spent 25 years in that business and wondered why, by the late 50s, would Wurlitzer market the same machine with 50 or 52 records. They had used 52 records (104 selections) starting with the 1500 of 1952 which intermixed 78s and 45's. A lot of locations had Wurlitzer remote control wallboxes. When the 2300 came out in 1959, (the first year of stereo jukeboxes), they offered 50 record models that could work with competitors wallboxes. I don't think many of the 52 mono jukeboxes were being sold by then except to upgrade a diner or a place with a lot of existing wallboxes. The old wallboxes could stay along with the same 52 records and a new machine rolled in. I only ever saw one 2504 in my years in the business. Most were usually the 2510 50 record models like yours.

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www.wrdv.org
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 Post subject:
PostPosted: Jan Sat 24, 2009 8:18 am 
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Doug VanCleave wrote:
Hi-Fi in Fiberglass wrote:
... Speaking of the Cobra,is the "power point" type of cartridge they used on the early Zenith Cobras as well as Motorola Calypso harmful to records?


Don't confuse a Cobra plug in cartridge with a Power Point. They were different. The early moving vane Cobra cartridges were state of the art. The later ceramic version was not as good but it was still better than some of the competition.


Hi Doug,
Yes you're right,I didnt mean to confuse them,I was refering to the later Cobra type,the same style used on the Calypso that takes the Astatic 93T stylus.
I have heard it said that they were hard on record grooves.


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 Post subject:
PostPosted: Jan Sat 24, 2009 2:01 pm 
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Hi-Fi in Fiberglass wrote:
...I was refering to the later Cobra type,the same style used on the Calypso that takes the Astatic 93T stylus.
I have heard it said that they were hard on record grooves.


In their day, they weren't the worst. They usually tracked around 6-grams, had good frequency response and were easy to replace. 6-grams are not as bad as it sounds on a mono record groove. At the time there were many other style ceramic cartridges that were much harder on the records.

If you have ever played a stack of 45-rpm records on a Dual 1229Q turntable with a Shure V15 type 3 moving magnet cartridge tracking just under 1-gram, anything less seems almost barbaric. :lol:

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 Post subject:
PostPosted: Jan Sat 24, 2009 3:00 pm 
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In the late ‘80s I had a friend that contracted for vending machine and arcade game companies as a mechanical technician. He could take an old pinball machine and really bring it back to its former glory. He was working on the mechanics of an early ‘50s Wurlitzer juke box but was out of his league when it came to the amplifier. He brought the amplifier chassis to me to be serviced. I replaced all of the leaky capacitors and the pair of half dead 6L6s.

The phono oscillator circuit for the Cobra cartridge was more sophisticated than the simple one found in Zenith equipment. It had an adjustable oscillator coil that you could tune and much like an AM radio, it could be slightly detuned for better high frequency response. I was impressed; The Cobra sounded as good as a magnetic cartridge.

I never heard that juke put back together but I was told that it was a major attraction at the arcade company for a few days because of its unbelievable sound. I understand that it found a new home rather quickly.

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 Post subject:
PostPosted: Jan Sat 24, 2009 3:48 pm 
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Doug VanCleave wrote:
If you have ever played a stack of 45-rpm records on a Dual 1229Q turntable with a Shure V15 type 3 moving magnet cartridge tracking just under 1-gram, anything less seems almost barbaric. :lol:


I had the 1229Q (no quad records at the time, though!) and it only started acting funny after I wanted to use it full time as a stacker! Too bad, since it's a nice table...adjustable arm angle was very nice.

They're finicky machines, though, don't you think? I noticed that if I didn't want to become a Dual EXPERT, that I would pretty much need a more rugged machine.

eric


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 Post subject:
PostPosted: Jan Sat 24, 2009 7:57 pm 
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I bought my 1229Q new back in the mid '70s. Duals have a few quirks but when you learn what they are, they are fairly easy to maintain. It's my favorite precision, fully automatic turntable.

If you look through any record changer parts and service manual, you will not find any reference to anything called a stacker. :roll:

Sorry, as an old TT guy that word bugs me. It was invented by a boutique store owner who didn't know the proper name of any of the parts on an automatic record changer. :lol:

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 Post subject:
PostPosted: Jan Sat 24, 2009 8:11 pm 
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I thought i would mention that Motorola used a "radionic" oscillator type cartridge in a couple of their radio/record players also. It was used with an early VM trio-speed changer and the hint that the changer was equipped with this cartridge is that the tonearm had a red tip on it. It unplugged just like the Zenith ones but pulled out from the end of the tip instead of pulling out from underneath the tip. I know as i have one of these and its a good sounding machine.
-Tony


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