CD-4 - The thin line between success and failure, but still in the fight!

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J. PUPSTER

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Was typing this when I read Sonik Wiz' post directly above.

Is the demodulator grounded to anything, or just to the turntable? To each other isn't really grounded.

Often the screw on the middle of a AC wallplate can be loosened and used as a ground. CAREFUL or you'll get a 110 volt jolt! If all else fails, find a water pipe or connect to a grounding rod in the ground. Ham radio & electronic supply distributors may still carry them. Copper rod with a bolt to screw ground wire to and shaped like a spike that drives into ground.
Sure, but the TT has a three prong grounded plug into a surge protector, shouldn't that ground it from there?
 

Sonik Wiz

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Like what exactly?
For a quick 'n dirty test find any old extension cord or device you really don't use any more & simply pull the center ground pin out of the plug with pliers. They come off easy. Crimp or solder this to the demod ground wire & insert the pin into the middle ground socket on the wall plate. If it helps then shop around for something nicer at a hardware store or such.
 

4-earredwonder

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Just a side step in threads here from Mr. Baggins' thread here.

My latest Panasonic SE-405 (as with all my Quad gear) is hooked up with Blue Jean LC-1 cables. I consider these to be pretty good quality shielded cables. The hum is not found with my other gear, like my Surround Master v2 etc.

I'll soon record in the hum I currently have in the Pany SE-405 and post here later for folks to listen to it. As I said before, I can usually hear voices in the background if cranked up; it could very well be some kind of local Radio interference IDK.

@barfle mentioned a part called a โ€œpower supply filter capacitorโ€, don't know if @Sonik Wiz replaced that one in my Marantz or not? But, all three Demodulators I now own have the same type of hum: Marantz CD-400B, JVC 4DD-5 & now the Panasonic SE-405. So even if it's that โ€œpower supply filter capacitorโ€, and you could find old one's out of a parts Demodulator for replacement, you'd still be using really old and unreliable parts IMO. So, are these โ€œpower supply filter capacitorsโ€ available new that would work in the Demodulators?

I probably mentioned this before, but when converting some of these 70's Japanese Cd-4 LPs I have to raise the recording-in amplitude by about 12-16 dbs to get a decent level with my current cart., an AT-15S. That just raises the levels across the board for stuff like hum to come out and it's very difficult to reduce after the fact. It might take 3 passes with Noise Reduction software to quiet it down which isn't good because I believe it is taking some dynamics out of the music and mudding it up a little IMO.
JP, before you commit thousands more to CD~4 demodulators, cartridges and even power conditioners, methinks you need to enlist the services of a competent licensed electrician to do a survey of your current incoming power source.


When I installed my main power gulping system years ago, I was experiencing electrical noises such as when my gas burner kicked in buzzing through my speakers. I had to bring in a new electrical panel, had my 'mains' grounded to a copper spike, and with it dedicated power outlets for all my high powered amps and paid special attention to my digital front end by installing its own dedicated outlet and power conditioners and wallah ... all that extraneous noise vanished and even the noise floor was dead silent!

And since you live in the U.S' most populous state with ever increasing energy demands, unless you've taken the steps I've outlined above, the main culprit might just be your need to upgrade your incoming power supply.

And even though I abandoned vinyl playback some years ago, even my high end digital system sounds better than ever ........

It really is ashame that CD~4 vinyl playback remains a hit or miss proposition but the noises you describe in your current system would drive me bonkers and is really unacceptable in this day and age.

New electrical panels, dedicated power outlets and even grounding your mains to a copper spike ain't cheap but in my situation it was an ultimate remedy which to this day brings me much joy and NO frustration like the kind you are currently experiencing.

If you've done ALL of the above and the problem still persists ....... I'm at a loss for words to further assist you in your quest for ultimate perfection in CD~4 playback .... if there is such a thing [and I don't mean to sound 'cheeky']!
 

J. PUPSTER

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Not unless the surge unit is itself grounded to something as discussed above.
It should be as far as I know.

JP, before you commit thousands more to CD~4 demodulators, cartridges and even power conditioners, methinks you need to enlist the services of a competent licensed electrician to do a survey of your current incoming power source.


When I installed my main power gulping system years ago, I was experiencing electrical noises such as when my gas burner kicked in buzzing through my speakers. I had to bring in a new electrical panel, had my 'mains' grounded to a copper spike, and with it dedicated power outlets for all my high powered amps and paid special attention to my digital front end by installing its own dedicated outlet and power conditioners and wallah ... all that extraneous noise vanished and even the noise floor was dead silent!

And since you live in the U.S' most populous state with ever increasing energy demands, unless you've taken the steps I've outlined above, the main culprit might just be your need to upgrade your incoming power supply.

And even though I abandoned vinyl playback some years ago, even my high end digital system sounds better than ever ........

It really is ashame that CD~4 vinyl playback remains a hit or miss proposition but the noises you describe in your current system would drive me bonkers and is really unacceptable in this day and age.

New electrical panels, dedicated power outlets and even grounding your mains to a copper spike ain't cheap but in my situation it was an ultimate remedy which to this day brings me much joy and NO frustration like the kind you are currently experiencing.

If you've done ALL of the above and the problem still persists ....... I'm at a loss for words to further assist you in your quest for ultimate perfection in CD~4 playback .... if there is such a thing [and I don't mean to sound 'cheeky']!
And I've mentioned that already in several posts about getting an electrician to check my situation, thanks!
 

J. PUPSTER

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Also, seems like since "all" of these old 70's Demodulators only have a 2 prong plug; that I wouldn't be the only one having these kinds of issues?

I see lots of three prong to two prong adapters but not a two prong to three prong adapter, I must be missing something?
 

4-earredwonder

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Also, seems like since "all" of these old 70's Demodulators only have a 2 prong plug; that I wouldn't be the only one having these kinds of issues?

I see lots of three prong to two prong adapters but not a two prong to three prong adapter, I must be missing something?
They're referred to as 'cheater plugs' and I was told though they may be a temporary solution they're not recommended!
 

4-earredwonder

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I'm running 3 surround systems in my house and since I did ALL of the above my systems are ALL free of any electrical anomalies ........ spend the $$$ on a licensed electrician instead of committing your resources to more 'vintage' CD~4 playback equipment!
 

4-earredwonder

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R.1b133afe5437bb434a63c8660ee850ed

WAITING FOR YOUR CALL, PUPSTER?
 

Quad D

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It should be as far as I know.


And I've mentioned that already in several posts about getting an electrician to check my situation, thanks!
Are you getting the same hum when using a regular phono stage (not CD-4)?
 

4-earredwonder

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and while we're on the subject, what does your current CD-4 set up consist of Ralphie? ๐Ÿคจ

I grew dissatisfied with vinyl playback YEARS AGO as I listen to a LOT of classical music and solo piano recordings and even a modicum of vinyl 'inclusion' used to drive me insane so I invested in a VERY high end digital front end and never looked back. Have all the CD~4 paraphernalia sitting in mothballs including a very pricey Sota Sapphire TT with a Grace tonearm and separate vacuum clamp to ensure the discs are flat on the platter but really don't miss any of that 'rigamarole' AT ALL! And I'm also a movie addict so I put my resources into a SONY 3D Laser projector and 120" screen and would much rather spend the loot on 4K movies than CD~4 records. And most new flicks also include ATMOS soundtracks which I can fold down to 7.4 ....... and IMO, are a LOT cheaper than 70's CD~4 discs!

But what it really comes down to ....WHATEVER FLOATS YOUR BOAT!
 

J. PUPSTER

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heya Mister P ๐Ÿค— maybe asking a silly question but worth a try? ๐Ÿคท๐Ÿปโ€โ™€๏ธ rather than grounding the Technics TT to the CD-4 demodulator, have you tried connecting the ground wire from the Technics to the Stereo preamp instead and then demodulating the CD-4 discs with it grounded that way? ๐Ÿคž
Yes, no difference. Also somebody mentioned someplace they unhooked the ground wire all together and it cured their hum, I even tried that, but that's definitely a no-no hum boiler maker.
 

fredblue

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Yes, no difference. Also somebody mentioned someplace they unhooked the ground wire all together and it cured their hum, I even tried that, but that's definitely a no-no hum boiler maker.
right oh, well i'm very sorry i wasn't more help in this particular instance but i shall keep my thinking balaclava firmly on to keep my brainz warm and will be right back with more handy (hopefully not useless!) hints.. soooon!! ๐Ÿ˜˜๐Ÿคฃ๐Ÿค 
 
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