Yes! I think a Kickstarter Campaign or IndieGoGo page might be beneficial and maybe raise some awareness of this project.
If we can aim for $500 US or LESS, definitely count me in.
If we can aim for $500 US or LESS, definitely count me in.
Can somebody write a brief description of what this thing will do?
Or post a link to something concise, thorough, yet understandable?
Chucky, would there be any benefit to putting it up on Indiegogo?
Hi
Back in the 70's JVC worked out how to modulate at high frequencies (above say 20 kHz) the additional information that permitted the decoding of discrete 4 channels, the system had real problems in terms of increased record wear and noisy dropouts plus the need for a special cartridge.
see:
https://en.wikipedia.org/wiki/Compatible_Discrete_4
Not sure how many CD4 recordings were made.....perhaps one of you guru's can assist?
Regards
Chucky
U
Omg. Thank you got the explanation and the link. Not sure I understood it all and I have a headache, but that's not your fault!
So, the device you're trying to build helps those who have them play these CD-4 records?
I thought you all were trying to convert analog records/tapes to digital, before they wear out, or something.
So, if you're trying to build a demodulator, does that mean many or all of you don't have one already?
Or you're building a better one? Am I understanding the situation?
Lou has told, that his new Demodulator would have a channel separation of 35 dB instead of the typical Demodulators with 30 dB. I think, that there are many fans, who have further on playing their CD-4 records direct with players and Demodulators like me. So I mean, that more orders for the new Demodulato will come . I self own 400 CD-4 records and would pay also $ 700 for a new Demodulator.
Dietrich
My uneducated guess is that a sensible approach would be to make a hybrid product, one that uses Dorren's hardware in the front end and DSP onwards.I have been giving the topic some background thinking time since the start of this thread and the main problem is how to deal with the varying levels of the high frequency carrier tone and the subsequent need for level calibration to match all the cartridge output levels. You will note that the existing SM box has no provision for adjustments and so if we were to cheat and use the existing SM electronics we need to be tricky. Currently my thoughts are to use an AGC (automatic gain control) approach on this carrier to unify levels......................still thinking!
I've been thinking about CD-4 demodulator design for 7 years since I started reading about it. I'm surprised AGC wasn't used on the carrier. What about taking it a step further with error correction via interpolation in the digital domain? Maybe borderline-playable records would have less harsh dropouts.
What price did they go for?
Regards
Chucky
You can use two boxes, one for the analog circuitry and the other for DSP.Need to stick to existing SM box.
You can use two boxes, one for the analog circuitry and the other for DSP.
I'd be in for the DSP box if it allows the input of a digital disc player, using specially prepped discs.
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