Any chance an Ortofon Super OM 40 will work with CD-4

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HiVision99

Member
Joined
Feb 5, 2017
Messages
41
Location
Houston, Tx
Main question is in the header.... I've read and read and read thru these posts and can't find enough info that would answer this. I have one available (Ortofon Super OM 40) for not much money. For what it's worth, it's spec'd out to 30kHz at the top end of its response. Any chance it would have enough usable signal at 45kHz where the carrier resides for the demodulator to lock onto..? Overall, I really like the sound of the (lower end) Ortofon cart I already have. And to elaborate, I just picked up a Lafayette CD-4 demodulator. By the way, will that Lafayette accept line level or only phono stage inputs? (I absolutely cannot find a user manual online. I have one for my SQ-W now but need one for the CD-4). Thanks for your help!

Sam
 
All CD-4 decoders accept only cartridge leads. They are preamp and decoder in one.
I wouldn't expect that cart to work but I don't know for sure after those AT carts. Disclaimer: I still haven't changed my cart-to-decoder wiring and don't get consistent good playback throughout an entire side on any CD-4 record (but close, and those first few songs are great).
 
All CD-4 decoders accept only cartridge leads. They are preamp and decoder in one.
I wouldn't expect that cart to work but I don't know for sure after those AT carts. Disclaimer: I still haven't changed my cart-to-decoder wiring and don't get consistent good playback throughout an entire side on any CD-4 record (but close, and those first few songs are great).

Thanks for the reply and insight. The more I read up, I see this Audio Technica AT440MLb would be at least a good contender. And it seems to have rave reviews even comparing it up against the better Ortofons. $200 bucks is fairly reasonable too. Plus it's a microline stylus. I've read that (the Quadfather) recommended its forerunner, the AT440MLa and claimed he got great results. The demodulator's due in in a few days so we'll see, lol. It's a fun pursuit, regardless. At any rate, I'd like to have Quadradiscs to play along with my SQ/RM collection. There are a number of titles in CD-4 quad that are only available otherwise on Q8 tapes.
 
Thanks for the reply and insight. The more I read up, I see this Audio Technica AT440MLb would be at least a good contender. And it seems to have rave reviews even comparing it up against the better Ortofons. $200 bucks is fairly reasonable too. Plus it's a microline stylus. I've read that (the Quadfather) recommended its forerunner, the AT440MLa and claimed he got great results. The demodulator's due in in a few days so we'll see, lol. It's a fun pursuit, regardless. At any rate, I'd like to have Quadradiscs to play along with my SQ/RM collection. There are a number of titles in CD-4 quad that are only available otherwise on Q8 tapes.

I believe the AT440 is amongst the line of stylii that Audio Technica are discontinuing. You may want to check this to be certain. If it is the case you may want to get one sooner rather than later as IIRC the new range with the cheapest microline stylus is more expensive.
 
The OM 40 has a Fritz Gyger stylus
- Stylus type: Nude FG 70
- Stylus tip radius: r/R 7/70 µm

I have always wondered if this kind of stylus would be good for CD-4. I also use a Lafayette CD-4 demodulator. Want to make sure you have a low capacitance cable (like a Blue Jean LC-1). Without that low capacitance cable, I can't get anything to work well with the Lafayette (including a AT44MLa).

vinylguy4
 
The OM 40 has a Fritz Gyger stylus
- Stylus type: Nude FG 70
- Stylus tip radius: r/R 7/70 µm

I have always wondered if this kind of stylus would be good for CD-4. I also use a Lafayette CD-4 demodulator. Want to make sure you have a low capacitance cable (like a Blue Jean LC-1). Without that low capacitance cable, I can't get anything to work well with the Lafayette (including a AT44MLa).

vinylguy4

For any cartridge to work well for CD-4 playback, it MUST have adequate ultrasonic (30kHz ~ 45kHz) channel separation. It isn't enough to just be able to play those frequencies. I very much doubt that the OM40 will work, and if you like Audio Technicas you should find an AT15Sa instead of a 440MLa. Shibata is the only stylus shape that was intended for CD-4 playback. Other 'fine-line', 'micro-ridge' and 'hyper-elliptical' designs are similar ... but they are not the same. The CD-4 carrier signal is located at a different place on the LP's groove wall, and the stylus must be able to track both locations at the same time. If the stylus tracks too low in the groove, it will not capture the carrier frequencies properly. Like I said, it isn't just about frequency response. Here is some interesting reading on the topic:

http://www.cieri.net/Documenti/Altr... of view about the quadraphonic evolution.pdf
 
For any cartridge to work well for CD-4 playback, it MUST have adequate ultrasonic (30kHz ~ 45kHz) channel separation. It isn't enough to just be able to play those frequencies. I very much doubt that the OM40 will work, and if you like Audio Technicas you should find an AT15Sa instead of a 440MLa. Shibata is the only stylus shape that was intended for CD-4 playback. Other 'fine-line', 'micro-ridge' and 'hyper-elliptical' designs are similar ... but they are not the same. The CD-4 carrier signal is located at a different place on the LP's groove wall, and the stylus must be able to track both locations at the same time. If the stylus tracks too low in the groove, it will not capture the carrier frequencies properly. Like I said, it isn't just about frequency response. Here is some interesting reading on the topic:

http://www.cieri.net/Documenti/Altr... of view about the quadraphonic evolution.pdf
May I ask what your opinion is on the Audio Technica AT20SLA. Is it an earlier version of AT440Mla and AT440Mlb. It's my original cd-4 cart from way back with very little usage. It worked fantastic back in the day. Are there better ones available today.
Thanks.
 
May I ask what your opinion is on the Audio Technica AT20SLA. Is it an earlier version of AT440Mla and AT440Mlb. It's my original cd-4 cart from way back with very little usage. It worked fantastic back in the day. Are there better ones available today.
Thanks.

The AT20SLa is virtually identical to the AT15Sa, and an excellent choice for CD-4 playback. The AT20S (and it variants) is supposedly a hand-picked AT15S. I have an AT15Sa that is installed on my dedicated CD-4 turntable (a Rega P3-24 with Incognito-wired RB300 tonearm), and I bought a new/old stock ATN20 replacement stylus for it ... not because I thought it would be an improvement, but because I found it at a great price.
 
The AT20SLa is virtually identical to the AT15Sa, and an excellent choice for CD-4 playback. The AT20S (and it variants) is supposedly a hand-picked AT15S. I have an AT15Sa that is installed on my dedicated CD-4 turntable (a Rega P3-24 with Incognito-wired RB300 tonearm), and I bought a new/old stock ATN20 replacement stylus for it ... not because I thought it would be an improvement, but because I found it at a great price.
Thanks for the reply. Soon I will be hooking this baby up again after over 30 years. That is if my JVC demodulator still works. If not then I'm hopeful that the Involve people will come through.
 
Thanks for the reply. Soon I will be hooking this baby up again after over 30 years. That is if my JVC demodulator still works. If not then I'm hopeful that the Involve people will come through.

The JVC demodulator is a tried and true unit. It is also the model that most CD-4 circuitry was based on, and several manufacturers sold the JVC under their own brands. The only issue that usually comes up is the 2-ch/4-ch switch on the back that allows a Moving Magnet phono signal to be directed to another preamp for 2-channel or matrix LP playback. Cleaning the switch with DeOxit can help, or you can just replace the switch. I got my JVC on eBay for about $100 from a Canadian seller who had a number of brand new units in sealed boxes. I had a Marantz CD-400B (still do actually), but it started to have issues. I should really offer it for sale to someone who needs parts from it.
 
The AT20SLa is virtually identical to the AT15Sa, and an excellent choice for CD-4 playback. The AT20S (and it variants) is supposedly a hand-picked AT15S. I have an AT15Sa that is installed on my dedicated CD-4 turntable (a Rega P3-24 with Incognito-wired RB300 tonearm), and I bought a new/old stock ATN20 replacement stylus for it ... not because I thought it would be an improvement, but because I found it at a great price.

I recently bought a AT150Sa and it does at least as well as my AT20SLa on my system, both have shibata stylus.
They are discontinuing the AT150Sa so are under 300 bucks at some sites. The stylus' on one the new lines of AT will fit the AT150SA so won't go obsolete.
If you have the AT20SLa, then you should be good.
Unfortunately the AT20SLa stylus will not fit the AT150SA.

vinylguy4
 
The OM 40 has a Fritz Gyger stylus
- Stylus type: Nude FG 70
- Stylus tip radius: r/R 7/70 µm

I have always wondered if this kind of stylus would be good for CD-4. I also use a Lafayette CD-4 demodulator. Want to make sure you have a low capacitance cable (like a Blue Jean LC-1). Without that low capacitance cable, I can't get anything to work well with the Lafayette (including a AT44MLa).

vinylguy4

Just a quick question regarding your Lafayette CD-4 demodulator. Does the "Direct Output" simply pass through the phono-level signal straight from my cartridge to my receiver's phono stage (for matrix LP's, etc...)? Thanks! Sam
 
Just a quick question regarding your Lafayette CD-4 demodulator. Does the "Direct Output" simply pass through the phono-level signal straight from my cartridge to my receiver's phono stage (for matrix LP's, etc...)? Thanks! Sam

I believe the phono input is passed straight to the direct output. IIRC, I did open the case one time to check that.

vinylguy4
 
I believe the AT440 is amongst the line of stylii that Audio Technica are discontinuing. You may want to check this to be certain. If it is the case you may want to get one sooner rather than later as IIRC the new range with the cheapest microline stylus is more expensive.

I just ordered one... $174 (NIB). Not too bad. Regardless, of its CD-4 performance, it'll be an improvement over the lower-end Ortofon that I have now. (And it doesn't sound half bad to begin with... I need a "brighter" sounding cartridge like the Ortofons or AT's tend to exhibit) In that regard, it's a good replacement/upgrade for what I have) We'll see how well it behaves (along with my tonearm wiring, etc) with this demodulator. Lol
 
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For any cartridge to work well for CD-4 playback, it MUST have adequate ultrasonic (30kHz ~ 45kHz) channel separation. It isn't enough to just be able to play those frequencies. I very much doubt that the OM40 will work, and if you like Audio Technicas you should find an AT15Sa instead of a 440MLa. Shibata is the only stylus shape that was intended for CD-4 playback. Other 'fine-line', 'micro-ridge' and 'hyper-elliptical' designs are similar ... but they are not the same. The CD-4 carrier signal is located at a different place on the LP's groove wall, and the stylus must be able to track both locations at the same time. If the stylus tracks too low in the groove, it will not capture the carrier frequencies properly. Like I said, it isn't just about frequency response. Here is some interesting reading on the topic:

http://www.cieri.net/Documenti/Altr... of view about the quadraphonic evolution.pdf
Very informative read. Thanks for passing that onto me. I'm learning as I go. But half the fun (to me anyway, is experimenting) I already have a nice collection on matrix encoded LP's and Q8 tapes and even a few Q4 open reels and deck (along with modern SACD/DVD-A) so this Quadradisc pursuit is just a fun add-on. I have hope that this will work eventually with the usual tweaking. But I really appreciate all of the educational posts and info. That's made it a LOT easier. -Sam
 
I believe “HiVision99” already found a solution, but if you don´t mind, I continue this topic.

Yesterday evening I tried to get my CD-4 setup working. I have a Sansui QRX-7001 receiver and a Dual 510 turntable with Ortofon Super OM40 cartridge.
I have a Sansui 7” CD-4 adjustment record and I used that to adjust my equipment. I was able to get pretty good front-back separation. When listening to music, loud parts were very distorted and even the smallest scratches made very loud pops. Result was no good.
Before I say OM40 is not suitable for CD-4 reproduction, I´d like to remind that it could be just me who couldn´t do the adjustment right. Or maybe a worn out LP´s I have? My receiver is fully serviced 3 years ago by a repairman who is specialized in vintage gear.
I have alsoa Ortofon Super OM30 with Nude Fine Line stylus. I think I´ll try that one too. I contacted Ortofon customer service and they said, not surprisingly, that 2m Black would be the best choice. It is also a very expensive choice.

My question about Audio-Technica cartridges is, what is the difference between AT440MLa and MLb ?

How about anti-skating adjustment, my Dual has adjustment for spherical and elliptical stylus + something that says “CD-4”. How is that different from the others?
 
I ask Quadzilla where the information about the carriers being at a different level (physically) from the audio frequencies in the groove came from. It has always been my understanding that the carriers are engraved the full length of the groove based on information from RCA/JVC.

Other than that, I completely agree that a CD-4 cartridge must have both response AND separation at ultra-sonic frequencies. That's why most cartridges not designed for CD-4 will fail, in spite of claims by the manufacturer.

I can't remember the exact difference between the AT440MLa and AT440MLb other than I know it has to do with the stylus construction. Performance is similar and I know I've read about at least one MLb user having success with CD-4.

The more contact there is with the groove wall from the stylus, the more friction and the greater anti-skating force necessary. That's why manufacturers of CD-4 turntables had a separate scale or adjustment for conical, elliptical, and CD-4. That being said, CD-4 is much more critical for anti-skate and the final setting must be made by adjusting it for minimum or, ideally, no distortion from both channels rather than just relying on a scale setting.

Doug
 
For any cartridge to work well for CD-4 playback, it MUST have adequate ultrasonic (30kHz ~ 45kHz) channel separation. It isn't enough to just be able to play those frequencies. I very much doubt that the OM40 will work, and if you like Audio Technicas you should find an AT15Sa instead of a 440MLa. Shibata is the only stylus shape that was intended for CD-4 playback. Other 'fine-line', 'micro-ridge' and 'hyper-elliptical' designs are similar ... but they are not the same. The CD-4 carrier signal is located at a different place on the LP's groove wall, and the stylus must be able to track both locations at the same time. If the stylus tracks too low in the groove, it will not capture the carrier frequencies properly. Like I said, it isn't just about frequency response. Here is some interesting reading on the topic:

http://www.cieri.net/Documenti/Altr... of view about the quadraphonic evolution.pdf

Quadzilla, Have you tried the AT440MLa? It does perform well. The microline stylus is an improvement on Shibata, and it performs very well. Also, it lasts and performs well for a long time. I'm not criticizing the AT15Sa, I'm sure it's a fine cart. But isn't that a quad era cart? Can you still get the stylus for it?
The Quadfather
 
I ask Quadzilla where the information about the carriers being at a different level (physically) from the audio frequencies in the groove came from. It has always been my understanding that the carriers are engraved the full length of the groove based on information from RCA/JVC.

Other than that, I completely agree that a CD-4 cartridge must have both response AND separation at ultra-sonic frequencies. That's why most cartridges not designed for CD-4 will fail, in spite of claims by the manufacturer.

I can't remember the exact difference between the AT440MLa and AT440MLb other than I know it has to do with the stylus construction. Performance is similar and I know I've read about at least one MLb user having success with CD-4.

The more contact there is with the groove wall from the stylus, the more friction and the greater anti-skating force necessary. That's why manufacturers of CD-4 turntables had a separate scale or adjustment for conical, elliptical, and CD-4. That being said, CD-4 is much more critical for anti-skate and the final setting must be made by adjusting it for minimum or, ideally, no distortion from both channels rather than just relying on a scale setting.

Doug

Doug G You are correct in your assessment about where the subcarrier resides in the groove. They're mixed in with the main audio, and sent to the cutting head as one signal per groove wall. Think of it like the stylus is like the tires on your car on a dirt road. The tires follow the changes and ridges of the road and stay on it. However, every now and then you hit that patch of hard clay where the surface has small washboard like ridges and the tires just tend to skate over them without actually going into the valleys, they just hit the tops of the "modulations" without following them into the depth of them. As a driver, you can feel the car losing it's grip. Well, that's what a bad stylus does on a CD-4 subcarrier. It follows the main audio, but those fine modulations just produce a skating effect and the stylus doesn't follow the surface of the vinyl into the valleys. the valleys are fine and close together, unlike the main audio, which has larger valleys the stylus can follow. The lower the frequency, the larger the valleys and vice versa. The problem is that with the speed of the record and the frequency involved, the stylus has to be thin enough to fit between the peaks and fall into the valleys, otherwise the subcarriers will not be accurately reproduced, and you will not get good CD-4. If the stylus just skates over the peaks, you get degraded subcarrier, and the PLL circuit can't get a good lock on it. The stylus shape is the most important thing in CD-4. I have found that the frequency response of the cartridge itself is less important, probably because the cartridge manufacturers underrate them. In the case of the AT440MLa, it's only rated out to 20KHZ which is supposed to be the upper limit of human hearing,though most people's ears can only do about 15KHZ. I know this, because that's how an analog TV repairman knows he's getting old, when he loses the ability to hear a defective, laboring horizontal oscillator in an old CRT television. It's 15KHZ, and the old guy can't hear it, but the young guys are going crazy because they hear it, and it's driving them batty. But I digress. The AT440MLa works, and it works well, in spite of the rated frequency response. This means it's reproducing out to 45KHZ, or it wouldn't work. The main reason for the low capacitance wiring is to make sure the capacitance of the wiring together with the wire's inductance doesn't form a pi type low pass filter and filter out the subcarrier. that's also the reason the cables are kept short, to keep both the total capacitance and inductance low. This puts the roll off frequency above the subcarrier frequency. A true CD-4 turntable has low capacitance wiring inside the tonearm as well as from the tonearm terminal board to the RCA output jacks. In CD-4 the subcarriers are responsible for the front to back separation. Left to right separation is maintained by the fact that left is recorded on one groove wall, and right is recorded on the other groove wall, along with their respective subcarriers. This is called vector modulation. The demodulator inside is actually two demodulators, one for left, and one for right. They operate independently of each other.
The Quadfather
 
Stumbled about this thread accidentally today. While I can't answer the original question, I can ascertain everybody in the forum that I had and still have the best CD-4 results with non Shibata good quality MC cartridges like Ortofon MC-30 Super and similar with Van-den-Hul or other "modern" styli plugged into a MCA 76 before it goes into the CD-4 demodulator. I recently compared this cartridge to a AT-20 SLA, which is for many the best CD-4 cartridge, on the same arm and turntable and the result was so much in favor of the MC-30 that I probably will start to offer all my original CD-4 cartridges soon. None of the difficult CD-4 records like Barry Manilov or the last track on BW Stevensons Calabasas are a problem with such a MC cartridge.
When I started into Quad more than 20 years ago I tried an MC-30 accidentally, because it was mounted on my turntable and the results were good, but I didn't know how good because I had no comparison. When I learned more about quad I bought and tried many of the CD-4 cartridges, most of them were still new. The results were not so good and for years I've blamed my setup for it. But now, since more than 2 years I've returned to the MC-30 again and CD-4 was never better!:sun
 
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