If you could purchase any CD-4 demodulator.....

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fredblue

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a fully functioning one! :LOL:

only the Marantz CD-400B i got a couple of years ago works without any problems, my 4 other units all have issues.


afaik the Marantz is essentially "just" a JVC 4DD-5 with auto carrier lock but it works first time every time and its been way more reliable than either of my actual 4DD-5's, so far.. one of the 4DD-5's only demodulated down one side of the room (brilliant!) and now is totally useless, while the other one does work but is temperamental, some days it works like a champ but most of the time its having none of it!

the Grundig Quadro i got about 5 years ago was a great little gizmo but after several years of faithful service it suddenly started leaking a bit of something out of the back of the "Blend" switch so i stopped using it.

if Involve were to release a CD-4 unit tomorrow i'd be first in line for sure! 🙏
 

Doug G.

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It would be between the Panasonic SE-405 and Technics SH-400. I may give the edge, in fidelity, to the SE-405 but the SH-400 has the cool meter and is so dang easy to adjust.

Plus, 15 years ago, or so, neither one cost me over 50 bucks. :D

Doug
 

surround.sound.enthusiast

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This is a fairly tough question, as there is quite a list of outboard demodulators I'm interested in and eventually want.

I'll say, first, I'm with fredblue and anticipant of the day that Involve Audio are able to make their demodulator. Boy, that'll be a sweet gift to all of us die-hard quaddies!! (Fred - I just got my hands on a Grundig CD-4 myself. What color something started leaking out of your blend switch, clear like contact lube or colored like melted something or other?)

But otherwise I have to say a JVC/Victor CD4-1000, which are impossibly rare. I'd love to have an entire JVC/Victor 4-channel Laboratory set-up as my core quad system, with the matching JP-V1000 pre-amp, two JM-S1000 stereo power amps, and two SEA-80 equalizers. There's always at least one piece of quad gear we can dream about... (unless you're rustyandi, that man seems to have every piece of candy!).
 

fredblue

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This is a fairly tough question, as there is quite a list of outboard demodulators I'm interested in and eventually want.

I'll say, first, I'm with fredblue and anticipant of the day that Involve Audio are able to make their demodulator. Boy, that'll be a sweet gift to all of us die-hard quaddies!! (Fred - I just got my hands on a Grundig CD-4 myself. What color something started leaking out of your blend switch, clear like contact lube or colored like melted something or other?)

But otherwise I have to say a JVC/Victor CD4-1000, which are impossibly rare. I'd love to have an entire JVC/Victor 4-channel Laboratory set-up as my core quad system, with the matching JP-V1000 pre-amp, two JM-S1000 stereo power amps, and two SEA-80 equalizers. There's always at least one piece of quad gear we can dream about... (unless you're rustyandi, that man seems to have every piece of candy!).
it was clear liquid and slightly thick, not much at all tbh but i panicked at the sight of it and unplugged the gizmo right away and banished it to the closet! 😝
 

senorverde

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One with an auto carrier lock. I have a pretty beat up Claricon unit (pretty much the same as the one Lafayette sold) that works pretty well but I wouldn't mind getting a nicer Technics/Panasonic unit so I can have the option to mate it with a strain gauge cart if I ever come across one.
 

Q-Eight

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I've got a Technics SH-400 and that's after going through a number of them. I've had the Pioneer QD-240, several Panasonic SE405's, and a Marantz 400. Whomever said that all demodulators are built equal must've never done any back-to-back testing.

But, then again, I ran one of those Ed Saunder's "CD-4" cartridge/stylus combos for a while and learned how poorly that performed as well.

But back to the demodulators.... I've found the Pioneers were good and quiet, but with the same cartridge/stylus I have NOW (the AT 440MLa), the Pioneer can't match the Technics for separation. It seems to hit a brick wall, like it's only designed for 10-12db of front to rear separation. The Technics can go 20+, almost making things that appear in the front very near silent in the back.

The SE-405's I've tinkered with DO NOT like my 440MLa. Both demod's I've tried are similar to the Pioneer; lacking in big time separation, difference being with the Panasonics, if you try to crank things up, you just get a splattery mess. They don't seem to like high levels of carrier. Turn everything down and sure, you get smooth, noticeable separation, but still doesn't compare to the Technics.

The Marantz I was allowed to borrow didn't seem to jive with the 440MLa at all.... it was a Marantz with the manual carrier adjust and if you turned the carrier control up all the way, I could barely get the radar light to flicker. Might have been something wrong with this one - not 100% sure. A friend uses it as a stereo pre-amp and he's happy with it.

'Bout the only thing I have bad to say about the SH-400 is I'm always tweaking the carrier level controls. It really does seem to vary from LP to LP. To it's benefit, it seems to LOVE high levels of carrier not distorting at all even with both controls cranked right up. It'll even hold carrier lock at low levels, just the performance will be seriously diminished.
If this box had an automatic carrier control, it might have been the one to get.
 

fredblue

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It's vaporware, but I would have loved to have gotten my hands on one of the demodulators Lou Dorren was working on when he died. From what I heard, it would have been the "Holy Grail" of demodulators.
RIP to a great man in Quadraphonics :cry: ..i hope all his CD-4 knowledge didn't die with him and the key info's documented somewhere safe.. 🤞
 

Doug G.

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I've got a Technics SH-400 and that's after going through a number of them. I've had the Pioneer QD-240, several Panasonic SE405's, and a Marantz 400. Whomever said that all demodulators are built equal must've never done any back-to-back testing.

But, then again, I ran one of those Ed Saunder's "CD-4" cartridge/stylus combos for a while and learned how poorly that performed as well.

But back to the demodulators.... I've found the Pioneers were good and quiet, but with the same cartridge/stylus I have NOW (the AT 440MLa), the Pioneer can't match the Technics for separation. It seems to hit a brick wall, like it's only designed for 10-12db of front to rear separation. The Technics can go 20+, almost making things that appear in the front very near silent in the back.

The SE-405's I've tinkered with DO NOT like my 440MLa. Both demod's I've tried are similar to the Pioneer; lacking in big time separation, difference being with the Panasonics, if you try to crank things up, you just get a splattery mess. They don't seem to like high levels of carrier. Turn everything down and sure, you get smooth, noticeable separation, but still doesn't compare to the Technics.

The Marantz I was allowed to borrow didn't seem to jive with the 440MLa at all.... it was a Marantz with the manual carrier adjust and if you turned the carrier control up all the way, I could barely get the radar light to flicker. Might have been something wrong with this one - not 100% sure. A friend uses it as a stereo pre-amp and he's happy with it.

'Bout the only thing I have bad to say about the SH-400 is I'm always tweaking the carrier level controls. It really does seem to vary from LP to LP. To it's benefit, it seems to LOVE high levels of carrier not distorting at all even with both controls cranked right up. It'll even hold carrier lock at low levels, just the performance will be seriously diminished.
If this box had an automatic carrier control, it might have been the one to get.
Although the 440MLa performs adequately, it isn't as good as one of the better vintage cartridges designed for CD-4. I have one and it generally works well but it comes up short when the going gets rough on more complex passages. It has a tendency to mistrack on the carriers in those situations and you get sandpaper.

My Empires, Pickering XUV, and Panasonic strain gauges all easily outperform it. Heck, even my AT912Sa does.

Doug
 

kfbkfb

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I wanted a Technics SH-400 since I first found out about it in the mid-1970s, I got one in 1992.

It uses the QSI5022 CD-4 IC which doesn't need a carrier level control, I don't understand why the SH-400 has carrier level controls.

Hardware CD-4 decoder:
The only other hardware CD-4 decoder I wanted was a JVC CD4-50, partly based on the description in Audio mag:
^^^
...the CD-4/50 is able to clean up the sound of quite a few CD-4 "problem" records to a remarkable degree.

Software CD-4 decoder:
Pspatial Audio


Kirk Bayne
 

sjcorne

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SH-400 is definitely the one to get, if only for the built-in "hi-blend" noise reduction. It's amazing how flipping that switch gets rid of most of the surface noise without seriously diminishing the high-end response. The Eagles' One Of These Nights is finally listenable! I also love having the separation & carrier crosstalk controls as easily-adjustable knobs on the front, rather than screws on the bottom or back of the unit.
 

Doug G.

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In writing about the AT440MLa above, I actually made an error. I wrote that the cartridge mistracks in the carrier frequency range with complex passages when I didn't really mean that. What I meant is that somehow, the cartridge, probably electrically, attenuates the carriers more than a cartridge designed for CD-4. It was probably designed like a typical 2 channel cartridge with the typical frequency response instead of the response of a typical CD-4 cartridge.

It obviously has better response and separation specs than the published ones but probably falls a bit short for CD-4. I mean, it generally works fine but I have had it "misbehave", sometimes.

Doug
 

Q-Eight

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It obviously has better response and separation specs than the published ones but probably falls a bit short for CD-4. I mean, it generally works fine but I have had it "misbehave", sometimes.
I went from the Ed Saunders to the 440MLa. But, I also invested in a Geodisk as it turns out, my cartridge alignment skills were severely lacking.
So far, I've found the 440 and my SH-400 really like each other. I've played some notoriously difficult CD-4 lp's on my setup with no issue. The sound is amazing. But the same stylus and cartridge certainly did not get along with the Panasonic demodulator nor the Marantz. I have been trying off and on to scoop one of the little common JVC units just to see how it likes my setup but so far I've not had any luck.
 

Owen Smith

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Oxford Dickie found the AT440MLa did not work well with his JVC 4DD-5 demodulators (he had two at the time) and moved that cartridge to his stereo deck. He managed to find a New Old Stock designed for CD-4 cartridge, AT15 I think (might have been AT16) and that worked much better.
 

par4ken

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If I could purchase any CD-4 Demodulator it would be Lou Doran's modern design. Many people here were ready to order as soon as it became available for purchase. Sadly Lou passed away before completing his project, I wonder if any working prototypes exist?
 

gvl_guy

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I think that yeah, a lot of people on this board wouldn't consider buying one for a reasonable price. But talk about limited appeal! :cautious: Maybe it could be built into something that's already semi-popular. I highly doubt anyone would manufacture something like this only because they wouldn't make a lot of money.
 

Doug G.

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I was signed up for Lou's demodulator.

Addressing the matter of why the SH-400 has carrier level adjustments when the QSI 5022 chips don't need it, Lou Dorren stated that he tried to convince the engineers who designed the SH-400 that they didn't need to include those controls in the unit but they were adamant. I think it was a "just in case" argument but, you know how it goes. Egos and all that.

I believe that explains why, regardless of where on the meter you set the carrier level, the demodulator seems to work, even with the displayed level very low. I can hear some distortion if I set the level way beyond the ideal level but that is far outside of a normal adjustment.

It's still fun to turn those controls and watch the level change on the meter, though. :D

Doug
 
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