Ok, I guess I better wade into this thread!
First off, a lot of things will "work" inspite of the published specifications for CD-4.
You can use a turntable that wasn't rated for CD-4 frequency response and that doesn't include either proper anti-skate adjustment for CD-4 nor low-capacitance tonearm wiring.
You can use "standard" interconnect cables that again are not "low-capacitance" as defined by the CD-4 specifications (and virtually every user's manual for a CD-4 demodulator or receiver)
You can use any cartridge you like........disregarding frequency response and/or its internal impedence.
And then, of course you can come right here and post about how great (or horrible) it performs!
In any discussion of this nature.....there are always subjective and objective observations. I usually do my best to define my comments so that you know a) the facts......and b) my own subjective analysis.
Anytime we start discussing whether A is better than B, or that C is a tremendous improvement you really have to start with my old favorite "What is your point of reference? (POR)". I've noted that even within this
thread some of you have at least made comment about what else you've heard and experienced. That is really good! But, one thing that "flavors" all these discussions is the rest of your setup.....as I noted at the beginning.......your TT, cables, cartridge......AND the demodulator under review!
Ok, here is my POR when it comes to CD-4. I have owned, modified, experimented with and/or listened to the following:
Demodulators: JVC 4DD5 (about 6 copies), JVC 4DD10, JVC CD4-1000 (Greg B. referred to it as the CD4-10 which is incorrect and could be confused with the 4DD10) and the JVC 5456X receiver (CD-4 built-in demod). The Technics SE-405 (about 4 copies), SE-405H, and SH-400 (3 copies). Lafayette CD-4, Marantz 400 (4 copies) and 400B (about 6 copies). Sansui QC-04 (4 copies) and of course the built-in demodulators in receivers by Sansui (QRX-7001/
8001/9001), Kenwood (9940), Pioneer (747, 949, and 949A) and the aforementioned JVC. And, probably a few others that I can't remember right now!
Cartridges: AT 12S, 14S, 15S, 20S. Empire (can't remember the model...but it was their "true" CD-4 cart) JVC 4MD-10, 4MD-20. Pickering UV-15 2000Q and 2400Q. Sansui SN-40. Shure M-24, V-15 III, IV, V. Stanton 780 4DQ. And, again probably a couple of others.............
TT: Teac (non CD-4 circa 1982), Kenwood 2050 (non CD-4 circa late '70s), Duals; CD-4 rated 1229Q, 2046, 2056 and a few others! And the designated CD-4 tables by Panasonic, JVC, and Sansui.
Many of these I "tested" by doing direct A/B or switching...calibrating, listening tests one after the other. I've used various combinations over fairly long periods of time (up to 8 years). Over the years I've often been asked and advised others on setting up for CD-4 playback.....and I've always tried to emphasis the basic requirements for CD-4 as the "starting point":
1) CD-4 capable turntable.....rated for CD-4 use and including low-cap wiring
2) Low-capacitance interconnect cables of the highest quality affordable
3) A "true" CD-4 cartridge capable of a full 20-45KHZ (minimum) frequency response.
Deviate from those 3 design requirements for CD-4 playback and as far as I'm concerned you've entered the "twilight zone"! It may work, it may not......it may sound good, it may not and you may or may not be actually hearing CD-4 as intended and designed!
I've often seen others here recommend one cartridge or another totally ignoring the 100K impedence requirement of ALL CD-4 demodulators....the Shure V-15's and Trackmaster come to mind. I've tested the
Shures.......I haven't tested the Trackmaster (no opportunity/desire). But, from technical publications and comments, I've seen it published that an impedence mis-match will cause a loss of High Frequency transmission and/or possible "ringing" between the cartridge and phono stage.
I do know that while I love my Shure V-15III for stereo/SQ/QS application.....I've never preferred it to most of the better "true" CD-4 cartridges when properly setup and adjusted with a good/new stylus.
I readily noticed high frequency distortion....not always really annoying.....but there nonetheless.
Ok, the above is my point of reference......and this thread is really dealing with the JVC 4DD5 rather than CD-4 in general. The 4DD5 has the honor of probably being the "first" commercially available CD-4 demodulator ....
...introduced around 1972 as CD-4 rolled out the gate towards the great
quadraphonic train-wreck.
Any claims that the JVC 4DD5 is the "best" demodulator....would have to presuppose that; No advancements were made to CD-4 demodulator design or production after 1972. And that gentlemen, is very easy to refute! JVC themselves brought out the 4DD10, and their last demodulator design
which can be found in the 5456X receiver uses the very same CD-4 ICs as the 1974 introduced Sansui QRX-7001. And, I'm not trying to denegrate JVC at all! They invented the format, and their CD4-1000 studio demodulator that I listened to at Nick P's house with its matched JVC cartridge
still is the best sounding CD-4 I've heard via long term memory.
In my research/modification/testing of the Sansui QRX-9001's demodulator I still had the memory of the CD4-1000 in mind as I listened. The "HG" Sansui demodulator is the closest to it I've heard! If I had to choose one or the other......I'd probably lean towards the JVC, but my astonishment when
I first heard the JVC probably plays a large part in that! Greg B's. comments I think accurately reflect his experiences at the time........remember he worked for RCA, and at the very beginning there wasn't much other than the 4DD5 to choose from. In my experience I would agree on his comments regarding the ANRS circuits and the Panasonic/Technics demodulators dullness, although I always preferred "dull" to overly sensitive and noisy (as he mentioned). I can say that part of the process in "creating" the HG Sansui is recalibrating the ANRS circuit to really open up the freq. response!
However, in comparing the "HG" Sansui vs. anything else.....its not even close! And, yes the 6 or so 4DD5s that I've used would rank well down the list. And, yes that is my own totally subjective opinion, with the only corroboration being the few others who have heard the "HG" Sansui. I've yet
to have any feedback from them that anything they've heard is better. (Feel free to chime in here guys!). And, I should note that when I tested the
4DD5.....it was with a "true" CD-4 cartridge, CD-4 capable TT, and low-cap
interconnects!
So, use what you want.....connected anyway you want. It's your ears and your enjoyment! But, I think you might really want to review the technical requirements before making strong recommendations to those that are just starting out trying to set up for one of the most technically challenging
audio formats ever brought to market!