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To give you an idea of the extent of the fake goods problem. In a 2016 survey by Apple - 90% of the 'Apple' chargers sold through Amazon - using the other the two methods..which includes the "Fulfilled by Amazon" option -  were found to be counterfeit....90%! 


« Time for a quick nixie tube video | Main | Review: Feiyu Tech Wearable Gimbal »

CX Discs - Better, Worse & The Same as a normal record

CBS envisioned all records made after 1982 utilising their CX encoding system, but if you've bought any music on vinyl since the mid 80s, you won't see a CX logo on the what was CX and what went wrong. Watch this video to find out. 
As always there are some great contributions in the comments - especially this link to a DIY CX decoder kit.

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Reader Comments (16)

Great video! CX! ;) I completely forgot about it, except for analog sound on early Laserdiscs!
(Which used a modified version of CX)

Found this:

A DIY CX encoder!
Here's the complete issue:

So it sems your RS120CX have the 3-chip CX solution as you pointed out in the video. eg. 3 op-amps IC's, one (the 13700D ) a bit unusual... TL084 is industry standard op-amps.
Would be fun to see which CX design board they put into the direct drive RS220CX!

Also, the CX line output of the Telefunken players needs to adjusted if a new pickup or different brand is fitted, normally the Audio-Technia AT-72K was factory fitted. This is according to the manual and a german Forum I've found.

October 19, 2017 | Unregistered Commenterpinswede

Great video as always!
Ok, this doesn't have anything to do with it, but after watching it, I've thinked about TECHMOAN!

The console of the car! Am I the only one who thinks it's... beautiful!

have a great day everybody!


October 19, 2017 | Unregistered CommenterClaudio

CBS patent for CX system:

More nice info, albeit in German:

October 19, 2017 | Unregistered Commenterpinswede

Thanks for that amazingly in-depth video! Sorry if I sent you down the rabbit-hole (or is that pot hole?) with the suggestion. You covered more than I could ever imagine.

And I'm so glad for having lived on both sides of the pond to really 'get' both sides of your muppets' jokes. Brilliant!

October 19, 2017 | Unregistered CommenterDahFinstah

Oh, forgot to mention: the short clips you pulled from the Telefunken (CX) record player were out-of-phase.

October 19, 2017 | Unregistered CommenterDahFinstah

Hi Matt,
I must confess I am impressed by the amount of time and research you put into these videos. I worked in the Hi Fi Trade for many years and never came across this one. I never knew of it's existence.

Perhaps it was because I sold hi end equipment that I missed it and perhaps the reps didn't want to push their luck.

When you think of the technology of today you could probably introduce something similar today but I don't think the purists would accept it.
Thank you for your time and effort. I really enjoyed this one.
PS I suspect the motor in the belt drive turntable was of the frequently generator type and that was were the bad speed issue was.

Jeremy Travis.

October 20, 2017 | Unregistered CommenterJeremy

Hi, Mat. Once again you have made an interesting, informative and entertaining video on a technology that I have never heard of, and I used to think I was well up on these things! I immediately checked all the many CBS albums in my collection - not a single CX amongst them!
Quadrophonic next? - another abortive technology that Sony and Columbia (and others) tried in the 1970’s.....

October 20, 2017 | Unregistered CommenterRoland

Thanks for all the comments and info - I've added the link to the DIY kit into the post as well.

October 20, 2017 | Registered CommenterTechmoan

I searched your site for Quadrophonics with just this comment being found. Is there any Quadrophonic equipment about I wonder? In the 70's I visited Decca's studios in London and saw them testing Quadrophonic remixes (someone and his two pianos I think?). Sometime later I also managed to get a copy of Simon & Garf's Bridge Over Troubled Water in a quadrophonic format (I still have it somewhere!) never managed to play it on any Quadrophonic kit, but it was compatible with stereo cartridge & turntable and was very high audio quality. I'd be interested to know if you've ever seen any equipment around?

October 21, 2017 | Unregistered CommenterSteve Wootton

Want albums to sound better, do what i did back in the early 80's, get a dbx compressor/dynamic range expander.. Heck of a difference and you get to play engineer

October 22, 2017 | Unregistered Commentertj treinen

Thanks as always for the video - and for your tenacity in making it happen.

I grew up in the late 1970s and pretty clearly recall compander mania - luckily, I only spent little money on a marked-down Sanyo SuperD unit. (And of course, my first cassette deck was equipped with Dolby B - an Elcaset type, by the way...) But I recall that CBS was tinkering with CX - and the only record I ever came across that was encoded with CX was at friend's place. He had bought the disc unknowingly (and, of course, had no CX decoder). He was and is no HiFi buff - but even to his ears it was obvious that the system was not compatible at all. At the end of every track one could hear very annoying noise trails - so saaad! :-)

And as you pointed out, the CD revolution was around the corner. CX was a futile attempt to prolong vinyl's life. By the way: I think it is very interesting to hear crackle even with CX turned on. I would have expected that a noise reduction specifically designed for vinyl would do better...

Speaking of prolonging vinyl's life: When it became clear that audio would go digital, Telefunken came up with the idea of using vinyl for bits and bytes...The prototype went under the name Mini-Disk (; as far as I know, the disc and stylus were based on the mid-1970s TED video disc. (

October 23, 2017 | Unregistered CommenterKurt Mueller

@tj treinen:

"Want albums to sound better, do what i did back in the early 80's, get a dbx compressor/dynamic range expander.. Heck of a difference and you get to play engineer"

These days, you can do that by digitizing your vinyls (preferably with a decent stylus/phono pre-amp/PC soundcard) and using any decent wave editor. As far as I can see, even the free "Audacity" does that job... (

October 24, 2017 | Unregistered CommenterKurt Mueller

Hi Mat,
In the same issue of Popular Electronics ( mentioned here for CX decoder DIY schematics and board, there is something more.
If you go to the page 21, you'd see the Technicolor model 212 VCR test.
I believe it uses yet another 1/4 inch tape cartridge format, but different from all those already discovered by you!

Maybe a good candidate for your next research?


About the cassette (from the Internet):
"Vintage early 1980s. Japan's Funai joined forces with Technicolor to create and market the Compact Video Cassette (CVC) system in the early 1980's. The CVC format uses quarter inch high video tape in a small cassette. This was the lightest and most portable recording system of it's time. Widely known as the "Technicolor Format," it used quarter inch cassettes that were generally only available in a 30 minute length - a factor that contributed to the format's downfall. In the late 80's, a few desperate retailers stuck with large inventories of unsold CVC units tried to unload them as 8mm VCR's." The picture quality that I saw this format produce back then was better than some VHS models of the same period."

October 25, 2017 | Unregistered Commenterpiwex69

Yes I'm aware of the format - and have read up on it - it's also not uncommon on ebay and there's a nice old all-in-one portable system that uses it that has a built in CRT.

October 25, 2017 | Registered CommenterTechmoan

Did CX only do compression or did it also change the tone by compressing some frequency bands more than others?

If it didn't change the tone, I find it highly amusing that the same mastering engineers that complained about a bit of loss of dynamic range were 10 years later caught up in a loudness war that squashed any dynamics in music completely to oblivion, much more drastically than CX ever did, looking at your wave comparison. Also, any music being played on a popular radio station at that time would have had much more compression applied to it than CX applied.

If you listen to the CX record without decoder, does it actually sound weird to you? I did not get that impression from the video.

March 8, 2018 | Unregistered CommenterErwin Timmerman

I'm not clued up enough on the process to know exactly what they did with the audio - however when I played the record back on it's own it sounded fine to me. The only way I knew some of the levels were different (the quieter sections were louder) was when I listened to it next to the original version. I've seen a few comments from people who had CX discs and weren't aware of this until seeing the video.

March 8, 2018 | Registered CommenterTechmoan

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