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

[TVB]

I followed the Lou Dorren thread as he was developing his demod every day for years and was quite shaken when I found out he had passed. With no further Adieu and beyond the shadow of a doubt my choice would be the LOU DORREN demod with the cartridge he was going to sell with it. Not all is gloom and doom though, because way back when, I was lucky enough to pick up a NOS jvc 4md20x and 4dd5 of a Canadian website and taped all of my favorite cd-4 records onto Q4's. My problem has never been the demod but that pesky little stylus. I get perfect decodes for about 20-25 records immediately after replacing the stylus. After that, I then begin to hear "dirty record noise", which sounds like the stylus has a dust ball on it. I bought 3 of those stylus's until they went out of production but was able to get all of my cd4's taped. In regards to the 4dd5, I do have to say how dumb do you have to be to put the controls on the bottom and back of the demod. Oh brother!

 

[kfbkfb]

After that, I then begin to hear "dirty record noise", which sounds like the stylus has a dust ball on it.

This might help (stylus cleaning without solvents):
http://www.pspatialaudio.com/stylus_care.htm

Kirk Bayne

 

[par4ken]

I followed the Lou Dorren thread as he was developing his demod every day for years and was quite shaken when I found out he had passed. With no further Adieu and beyond the shadow of a doubt my choice would be the LOU DORREN demod with the cartridge he was going to sell with it. Not all is gloom and doom though, because way back when, I was lucky enough to pick up a NOS jvc 4md20x and 4dd5 of a Canadian website and taped all of my favorite cd-4 records onto Q4's. My problem has never been the demod but that pesky little stylus. I get perfect decodes for about 20-25 records immediately after replacing the stylus. After that, I then begin to hear "dirty record noise", which sounds like the stylus has a dust ball on it. I bought 3 of those stylus's until they went out of production but was able to get all of my cd4's taped. In regards to the 4dd5, I do have to say how dumb do you have to be to put the controls on the bottom and back of the demod. Oh brother!

I agree about the stylus, I always had trouble with the inner grooves on CD-4 records. I found that switching to a moving coil gave much better results. I had two cartridges the same and with the one that I used the most I had the same sandpaper sound on CD-4 but that same cartridge still sounded fantastic with stereo/matrix records. The unit with less miles on it still worked perfect on CD-4.

I used a Grado cartridge back in the day and played a lot of vinyl, despite replacing the stylus regularly i'm now convinced that ANY amount of wear to the stylus is troublesome for CD-4.

The thing to do with CD-4 is to dub to tape as you did or better yet to the computer's hard drive.

 

[TVB]

Kirk, I cleaned those styli until the red paint was removed from the undercarridge of the stylus assembly with the discwasher special brush and stylus cleaning fluid. Have you tried the magic eraser stuff. If you do, where do you get it from?

 

[kfbkfb]

The Magic Eraser cleaner is available at Walmart type places and Grocery stores in the home cleaning products section (I bought mine at Walmart). I bought an AT-LP60 [not CD-4] just as a stopgap, my main turntable system needs upgrading, I don't play many LPs, I tried the Magic Eraser procedure but the stylus wasn't very dirty due to my lack of playing LPs.


Kirk Bayne

 

[TVB]

Thanks, im going to give it a try

 

[jaybird100]

Can anyone still fix a 4DD-5? Would it even be feasible anymore?

 

[Owen Smith]

Can anyone still fix a 4DD-5? Would it even be feasible anymore?

OxfordDickie did some work on his and said they're very easy to work on. Lots of discrete components, good quality PCB which tolerates heat well, etc,

 

[fredblue]

OxfordDickie did some work on his and said they're very easy to work on. Lots of discrete components, good quality PCB which tolerates heat well, etc,

did OD ever release any Quads from CD-4? do you know how he's keeping? i sincerely hope he is doing well.

 

[Doug G.]

Gosh, I have Shibata/line contact styli that have played way more records than what you guys are talking about and they are still fine. I know my S4000D/I and S440D styli are way beyond that.

Doug

 

[Owen Smith]

did OD ever release any Quads from CD-4? do you know how he's keeping? i sincerely hope he is doing well.

He never quite got around to doing CD-4 releases. I had a test transfer from him of a CD-4 and it sounded fantastic to me, but you know OD. Never satisfied with his work and always trying to do better. He was still making mods to his CD-4 turntable (separate from his stereo turntable) and mods to one of his JVC 4DD-5 demodulators.

OD is fully vaccinated against covid-19 (as am I) which these days counts as doing well. He's also now old enough to receive his UK state pension which has made him a bit less financially stressed. His mental health issues are better than they've been in recent years, but his nerve damage from diabetes continues to get worse. One foot tends to drag now if he's not careful. For a man I've only met in person twice years ago for a few hours on each occasion, I know more about him than many people I see on a weekly basis.

 

[Wurly1]

Hi Wurly1, do you have a system with PLL circuits?
I would be interrested to know which type the chips are, so my next Quadro amplifier gets much smaller.
(Normal Stereo PLL need a 19kHz carrier to activate them instead looking for the 36kHz carrier.)

No it does not have a PLL circuit. It simply tune the 30khz carrier and detect it (demodulate the signal) .

 

[par4ken]

Gosh, I have Shibata/line contact styli that have played way more records than what you guys are talking about and they are still fine. I know my S4000D/I and S440D styli are way beyond that.

Doug

You should be able to get more than 20-25 good playings from a stylus, but from experience stylus wear is a big factor in CD-4 playback.

 

[Wurly1]

You should be able to get more than 20-25 good playings from a stylus, but from experience stylus wear is a big factor in CD-4 playback.

From my experience, way more than 20-25 good playing! In fact i worry more about records wear than stylus wear but then again, their vinyl formulations make CD-4 quite durable.

 

[par4ken]

From my experience, way more than 20-25 good playing! In fact i worry more about records wear than stylus wear but then again, their vinyl formulations make CD-4 quite durable.

I've never played any CD-4 record over and over so as to worry about record wear. Yes JVC's Super Vinyl should be very durable, the audiophile labels even used it! While I never wore out any CD-4 records, I did wear out a lot of stereo LP's and a few SQ records as well.

 

[Sonik Wiz]

I've never played any CD-4 record over and over so as to worry about record wear. Yes JVC's Super Vinyl should be very durable, the audiophile labels even used it! While I never wore out any CD-4 records, I did wear out a lot of stereo LP's and a few SQ records as well.

Same here. It is legendary how many of us have purchased how many copies of some Pink Floyd's SQ discs because of wearing out.

In the end I think one of the best contributions of CD-4 technolgy was actually beneficial to stereo records; virgin vinyl, Shibata stylus, & half speed mastering.

 

[Doug G.]

You should be able to get more than 20-25 good playings from a stylus, but from experience stylus wear is a big factor in CD-4 playback.

Of course. The stylus tip has to remain able to trace those super sonic frequencies. I have written, elsewhere, about my two EPC-450C II styli, one that came on a used cartridge so I don't know its history, and the other one from a new cartridge. The former plays regular LP's fabulously but won't reliably play the inner tracks of a CD-4 record without distortion. The latter stylus plays everything beautifully. Obviously, the used stylus is worn enough to cause its limitation.

Doug

 

[kfbkfb]

http://www.pspatialaudio.com/stylus_wear.htm^^^
...the acceptable stylus-wear limit is reached for a conical stylus of 0.0007" (18µm) radius in under ten hours if tracked at 5 grams.

(also has some info about line contact stylus wear)


After reading this, I pretty much stopped playing records on my new AT-LP60, which has a conical stylus and ~3.3g tracking force.


Kirk Bayne

 

[Owen Smith]

After reading this, I pretty much stopped playing records on my new AT-LP60, which has a conical stylus and ~3.3g tracking force.

What is the purpose of having it if you can't play records with it?

 

[Doug G.]

I have always thought some get too obsessive about this. I have records over 50 years old and I have never really kept track of how long I have used any given stylus. In fact the stylus in my V15 Type III is from about 1979 and has been checked one or two times in its life and neither time has revealed any serious wear. It still performs perfectly fine with the same brilliance and detail it has always had.

Those old records still sound the same, too.

The V15 isn't the only cartridge I have used over the years, of course, but it has had its fair share of use.

Note also that, most of the alarming information comes from using extreme tracking pressure (3 - 5 grams) and wear of both record and stylus goes up exponentially from 1 - 1.5 grams and those pressures.

So, i think we need to just relax and enjoy our records.

Doug