CD 4 Distortion

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The Bushmaster

500 Club - QQ All-Star
Joined
Nov 24, 2012
Messages
599
Location
Ava. MO
O K guys...I've heard all kinds of reasons why CD 4 records have distortion usually on the last band on a side, but not always on the last band. I have one that I just got that has some distortion on band one and a lot on band 5 on side one only. Side two is near perfect.

What causes this damaged grooves? Might get it from the experts.
 
Depends on the album sometimes, too. I think there's a Cat Stevens CD-4 LP that is a notoriously grungy pressing.
 
If you haven't given it a thorough wet cleaning, that is my suggestion. I have had strange good luck with wet cleaning, even when the seller clearly cleaned the discs. I have experienced a weird grunge on Japanese records because of the humidity of the country, and possibly from putting the record in a plastic inner sleeve before the groove is dry. I have even had LP's arrive moldy after the online pic was beautiful. On a rare occasion, a second wet cleaning may be necessary. Hope this helps.
 
http://www.vinylengine.com/cartridge-alignment-protractors.shtml

If you are using a (non radial tracking) tonearm, it seems like the
problem is phono cartridge misalignment in the tonearm.

I realigned my phone cartridge in my tonearm and the CD-4 reproduction
(particularly on the inner grooves) improved dramatically (I'm using a
non CD-4 Shure V-15 Type III and a Technics SH-400 demodulator).

Kirk Bayne
 
I have tried both a AT15S and an AT14Sa mounted on separate heads. Mounted on a Dual CS721. If I go to a Grado MF-1 I no longer have the distortion. The MF-1 does a fair job of reproducing the 30,000 carrier and turning on the CD 4 radar light.
 
Not sure we are going in the right direction here. The distortion that I'm experiencing is just on certain loud instruments (sounds) and not on all CD 4 records. That includes two records that are the same.
 
Do you mean two copies of the same CD-4 record? A possible explanation would be unusual wear from a too-light tracking force. I did that myself long ago to a stereo record by having the tracking way too light on a cheap turntable, the reason being that instead of tracing the groove, the stylus floats and shaves off some of the peaks.
 
Yup...One with spot distortion (gravely) and the other good all the way through.

AT15S and an AT14Sa set at 1 1/2 gms tracking force.
 
Sounds like somebody might have damaged one of those two copies. Either by playing with a bad setup or during manufacture. By bad setup I refer to my mistake in 1979 of playing a new record on a fold-out portable record player with detachable speakers, a ceramic cart with the tracking too light. Seriously, I did that. Of course, I was 16 at the time and didn't know better.
 
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In that most of the distortion is in the rear channels that would explain why the Grado MF-1 plays perfectly.
 
I use an Audio Technica AT440MLa. I understand that it has been replaced with the AT440MLb, which I hear is just as good. It is rare that I hear distortion. I run it at about 1.75 grams. A lot of stereo carts run at 1.5 grams and that is probably what is recommended by Audio Technica, as it is sold as a stereo cart. But it has a microline stylus, and it plays CD-4 beautifully. Also, it's not particularly expensive, about $180.00 last time I looked. The advice about cleaning is good also.
The Quadfather

P.S. Bushmaster, I was trying to read the text on your logo, perhaps you could share that with us.
 
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Logo text... Mike's Folder 244 (Medium).jpg
 
The specs you quote are for stereo play. This cart is not sold as a CD-4 cart. My experience is that you just need a little more weight for the stylus to correctly track a CD-4 record. It doesn't hurt the records, I've been playing them that way for quite some time now, if the records were being harmed, the first manifestation of that would be poor CD-4 performance. And as I said, I get good CD-4 performance. I also get crisp, clean cymbals. I looked to see, since I haven't adjusted my balance in quite awhile, I'm actually tracking at about 1 7/8 grams, a little lighter than I had stated. You could probably run it at 1 3/4 without much problem. Remember that CD-4 records are made with super vinyl to combat record wear.
The Quadfather

Recommended tracking weight for this stylus is 1.4g.

See the specifications tab on this page: http://www.audio-technica.com/cms/cartridges/2cafc1c694070c54/

2.0g is outside of the recommended range, so mind you're not subjecting your records to extra wear!
 
How is it with clearance from the vinyl surface? I have one for general use and find it's more compliant than the average cart and the body tends to dip a little when in the stylus is in the groove. Mind you I also have the VTA more towards the rear to try and tame the sound a little.
 
The specs you quote are for stereo play. This cart is not sold as a CD-4 cart. My experience is that you just need a little more weight for the stylus to correctly track a CD-4 record. It doesn't hurt the records, I've been playing them that way for quite some time now, if the records were being harmed, the first manifestation of that would be poor CD-4 performance. And as I said, I get good CD-4 performance. I also get crisp, clean cymbals. I looked to see, since I haven't adjusted my balance in quite awhile, I'm actually tracking at about 1 7/8 grams, a little lighter than I had stated. You could probably run it at 1 3/4 without much problem. Remember that CD-4 records are made with super vinyl to combat record wear.
The Quadfather

As I'm poised to dip a toe into the CD-4 waters, my interest is piqued by your last comments that CD-4 records were made with super vinyl to combat record wear.

Reading through past QQ posts on the subject, I've seen some conflicting reports about how fussy CD-4 records can be and how they can (allegedly) be trashed if played using a non-compliant (non-Shibata?) stylus or whatever..?

Please forgive the potentially incorrect terminology throughout my post, hitherto I've only been an ever-so-humble SQ and QS vinyl spinner (SQ and QS may have some shortcomings but they seemed so much easier to handle, especially to a Quad vinyl rookie like yours truly, who hadn't so much as played a slice of vinyl in a decade or more up to the point I decided to go Quad vinyl..!) and as I am starting to acquire used CD-4 records right now, I want to make sure I am not picking up stacks of used CD-4 records that are to all intents and purposes useless.

Thanks in advance.
 
The only problem I have with clearance is that some records that have the leadout groove close to the label, sometimes the label scrubs a little. It still tracks the groove, but it's a little noisy. It does ride a little low. As far as stylus damage goes, they are long lasting. I'm on my second one, and I've had my cartridge since the early 2000's.
The Quadfather
 
I collected quad records of all the major types at the end of the quad era. But my first CD-4 demodulator was a cheap one. I couldn't find a good one and probably couldn't afford it if I did. My first cart was an AT14S which had a worn stylus. I couldn't find nor could I afford a replacement stylus. So I played the records and put up with the distortion. After awhile I gave up on getting decent sound out of CD-4 and disconnected the demodulator. I was under the impression that the carriers was never correctly pressed into the vinyl and the quad was unextractable without distortion. So I replaced my Shibata stylus with a new elliptical, and played my CD-4 records as stereo records through my Audionics Space and Image Composer (SQ decoder). A number of years later I found a JVC 4DD5 at an Alabama flea market and decided to give CD-4 another chance. I had to work on the demodulator, as it had a few bad capacitors, but I got it working. I found a new old stock stylus for the old cart off the internet, which I had just started using. I also found that the internet allowed me to find many records I had missed during Quad's commercial demise, including CD-4 records. I hooked up the demodulator and put on the new stylus, and for the first time I actually got mostly distortion free music. But those records had been mistreated by playing with an elliptical stylus. Yet they were playing well. I found that as I played more records it actually improved. The point is, the records are sturdier than a lot of people give them credit for. Once cleaned good, they usually play OK. The exception is when someone played them on a cheap BSR turntable with a crystal cart, it can wipe the carriers from the record. I only found one record like that. Most people who bought CD-4 records had the better gear because they cost a lot more than SQ or stereo records, about double. And if you weren't equipped to play them, you opted for the stereo version.

The AT440 MLa does have a Shibata type stylus, but the Microline stylus is an improvement on the Shibata design and will out perform an average Shibata, I believe. The Microline stylus will dredge up gunk from the groove that cleaning methods fail to get. I expect this on a new aquisition if it isn't still sealed in the wrapper it came in. After a few plays with you having to stop and clean the stylus, there is no more and the record will play flawlessly. I picked up some of my CD-4 records at flea markets mixed in with stereo records. They all play. So get you a good quad era turntable, and a new AT440MLb, which is the newer version, a good demodulator (the JVC 4DD5 is generally recognized as the best), and you should be on your way to good quad. You might want to get yourself a cartridge alignment protractor kit. Good alignment is necessary. And you will be tracking that cart at just under two grams, not 1.4 . Now be aware that turntables for CD-4 are required to have low capacitance wiring. It's more than just the lead wires, the tone arm wires have to be low cap too. That's why I say get a quality quad era turntable. The low cap wiring will be evident, because they are thick like video cables. Any of the major brands of the era will suffice. Marantz, Pioneer JVC of course (it's their system), Fisher, Sansui. It's a little more trouble getting it all set up, but once it's right, you'll know it. See the archives on setting up the demodulator. I have discussed this in detail in several postings. And as far as bad records go, you won't know until you try to play them, unless they're obviously scratched up. You probably won't find many that don't demodulate well. There are a few records that have a reputation as hard to track. The worst one most will agree is Cat Stevens Greatest Hits. Get that one to play well and you've hit CD-4 nirvanna! And yes, the records are made with super tough vinyl developed for CD-4. And when you want to play your SQ records, just turn your demod to the stereo setting and it serves as a preamp. It has to be plugged into the auxillary "line level" jacks, as it's output level is the same as a tape machine. You connect your SQ decoder in the tape monitor loop, and decode that way. Most SQ decoders have a tape connection so you can do this and still have a hookup for your tape equipment. The Microline stylus will not harm your SQ and QS records.
The Quadfather


As I'm poised to dip a toe into the CD-4 waters, my interest is piqued by your last comments that CD-4 records were made with super vinyl to combat record wear.

Reading through past QQ posts on the subject, I've seen some conflicting reports about how fussy CD-4 records can be and how they can (allegedly) be trashed if played using a non-compliant (non-Shibata?) stylus or whatever..?

Please forgive the potentially incorrect terminology throughout my post, hitherto I've only been an ever-so-humble SQ and QS vinyl spinner (SQ and QS may have some shortcomings but they seemed so much easier to handle, especially to a Quad vinyl rookie like yours truly, who hadn't so much as played a slice of vinyl in a decade or more up to the point I decided to go Quad vinyl..!) and as I am starting to acquire used CD-4 records right now, I want to make sure I am not picking up stacks of used CD-4 records that are to all intents and purposes useless.

Thanks in advance.
 
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