elguapo511
Senior Member
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- Sep 18, 2010
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- 210
and if I only have the LP and appropriate needle, will it not work?
What makes a turntable a quadraphonic turntable?
- Thread starter elguapo511
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Disclord
900 Club - QQ All-Star
Any turntable is quadraphonic if the correct stylus is used for CD-4 or an SQ/QS matrix album is played. So except for the few turntables that had a built-in CD-4 demodulator, any turntable is a quad turntable.
Doug G.
2K Club - QQ Super Nova
That's generally correct. A lot of beginning enthusiasts believe there is something magical about a quadraphonic turntable but it really is no different from a regular one except for having a CD-4 cartridge on it.
Another spec. is that, ideally, the wiring needs to be low capacitance to avoid attenuation of the ultra sonic frequencies before they get to the demodulator. Say, 100pF or less. But, I wonder how many turntables met this spec. even before CD-4 development.
I believe a turntable needs to have anti-skate to be successful with CD-4 too because the tracking of the two groove walls is more critical than with regular two channel stereo. Of course, most turntables already had this before CD-4 also.
Doug
Another spec. is that, ideally, the wiring needs to be low capacitance to avoid attenuation of the ultra sonic frequencies before they get to the demodulator. Say, 100pF or less. But, I wonder how many turntables met this spec. even before CD-4 development.
I believe a turntable needs to have anti-skate to be successful with CD-4 too because the tracking of the two groove walls is more critical than with regular two channel stereo. Of course, most turntables already had this before CD-4 also.
Doug
elguapo511
Senior Member
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It has been so long.... anymore thoughts on this as a priority necessity for my system?
is it all about low capaciitance?
is it all about low capaciitance?
Doug G.
2K Club - QQ Super Nova
Other than having a CD-4 cartridge, if that is what you want to play, yes. Low capacitance is a must for successful CD-4 reproduction. If the ultra-sonic signals get attenuated and the demodulator doesn't see them, there will be no demodulation of the front-back signals and, hence, no CD-4 quad.
I did mention anti-skate as a means of obtaining equal trackiing of both groove walls which is crucial for CD-4 also. So, in the end, it is a matter of those things combined for CD-4.
Matrix encoded records (SQ, QS,etc.) will play fine with any stereo cartridge and the capacitance doesn't really matter any more than with regular 2 channel records.
Doug
I did mention anti-skate as a means of obtaining equal trackiing of both groove walls which is crucial for CD-4 also. So, in the end, it is a matter of those things combined for CD-4.
Matrix encoded records (SQ, QS,etc.) will play fine with any stereo cartridge and the capacitance doesn't really matter any more than with regular 2 channel records.
Doug
Is there any difference in antiskating for stereo/SQ/QS and CD4? I know some turntables had separate numbers on the antiskating dial for conical/elliptical/shibata tips, but most only have one set of numbers.
Doug G.
2K Club - QQ Super Nova
A Shibata will create the highest skating forces of the three and anti-skate is more crucial with CD-4 as far as tracking and distortion. That being said, it is a matter of trying a setting and listening with CD-4. The markings don't mean all that much. However, I have found results are similar to other styli as far as VTF vs. anti-skate settings.
Doug
Doug
Most Japanese turntables (Technics, Pioneer, Sony, JVC, etc.) of the Quad era work fine for CD-4. Nearly EVERY brand of QUALITY turntable made from '74 forward will have low capacitance cables. If you have access to specs, as Doug mentioned, you'll know the actual capacitance of the cables. Many turntables have rear panel jacks, rather than dedicated (attached) patch cords. The wire in the tonearm and in the turntable chassis would also require replacement, which are much more involved than replacing a patch cord.
There are other turntable issues that can affect the CD-4 performance. Adequate tracking force is one. Too low a tracking force was often as bad for CD-4 as too heavy, sometimes worse. Either a stylus force gauge or balancing the tonearm so that dead-on horizontal equals 0g are most helpful in calibration. Think of the tonearm as a see-saw.
IF you're using multiple cartridges, be sure to move the counterweight by holding the weight itself. On an S-shaped tonearm, a common mistake is to move it by the disc with the tracking numbers itself. This maneuver completely "uncalibrates" the tonearm. Some cartridges have different physical weights. If there is a significant weight difference, re-calibrating the arm may be necessary each time the cartridges are switched.
Proper alignment can also affect CD-4 performance. An alignment gauge can be extremely helpful. Many turntables included an alignment device. Mofi's Geodisc is an example of an "aftermarket" alignment tool.
A CD-4 calibration disc is also most helpful for CD-4.
These procedures and devices become most helpful if you have little or no experience in setting up turntables.
Back in the day, our sales and support staff most often could get this dead-on without the aid of these devices! The key here was each person setting up dozens, even over 100 turntables per week.
There are other turntable issues that can affect the CD-4 performance. Adequate tracking force is one. Too low a tracking force was often as bad for CD-4 as too heavy, sometimes worse. Either a stylus force gauge or balancing the tonearm so that dead-on horizontal equals 0g are most helpful in calibration. Think of the tonearm as a see-saw.
IF you're using multiple cartridges, be sure to move the counterweight by holding the weight itself. On an S-shaped tonearm, a common mistake is to move it by the disc with the tracking numbers itself. This maneuver completely "uncalibrates" the tonearm. Some cartridges have different physical weights. If there is a significant weight difference, re-calibrating the arm may be necessary each time the cartridges are switched.
Proper alignment can also affect CD-4 performance. An alignment gauge can be extremely helpful. Many turntables included an alignment device. Mofi's Geodisc is an example of an "aftermarket" alignment tool.
A CD-4 calibration disc is also most helpful for CD-4.
These procedures and devices become most helpful if you have little or no experience in setting up turntables.
Back in the day, our sales and support staff most often could get this dead-on without the aid of these devices! The key here was each person setting up dozens, even over 100 turntables per week.
My turntable certainly wasn't quadraphonic. It was a Philips with those cool looking green touch buttons that lit up. It must have had high capacitance wiring. Couldn't get my Marantz demodulator to work good enough to be useable, but I preferred reels anyway.
We were a Philips dealer. As I recall, GA 212 was NOT low capacitance wired. The replacement GA-312, released in mid-late '74 WAS low capacitance.
(22) GA-212:
(22) GA-312:
If my memory is correct, the GA-312 changed four things:
1- Low-capacitance wiring
2- Black head shell
3- Tonearm lift at end of record
4- A servo mod to make it more reliable (not positive about this one)
A great vintage turntable. Note the round lit sensors on the turntable. The electronics below used a similar system for many functions, albeit with two silver plates and a red LED.
A couple years later, when Philips was trying to get their electronics into Pacific Stereo, we were gifted a high end system in our Chicago (IL/WI/TX/GA) region. We sold lots of Philips turntables. We didn't carry the other electronics. The system was offered in a sales contest for Sept - Dec '78 season. Happily, I won the system! I wasn't fond of the current (22) GA-877 Philips turntable included, so I returned it to stock for credit and replaced it with a Sony PSX-6 turntable, which also had red LED's with touch controls. Everyone scoffed at this system, until I played it for them. The power amp was 500W RMS @ 8 ohm. With an Ortofon MC-20 and Teac 3300, it ROCKED!
I still have the speakers, which are currently driven by an Onkyo 5.1 receiver on my #3 surround system. I have replaced the drivers. 12" woofers, dome tweeters and midrange.
photo from OakTree Vintage
(22) GA-212:
(22) GA-312:
If my memory is correct, the GA-312 changed four things:
1- Low-capacitance wiring
2- Black head shell
3- Tonearm lift at end of record
4- A servo mod to make it more reliable (not positive about this one)
A great vintage turntable. Note the round lit sensors on the turntable. The electronics below used a similar system for many functions, albeit with two silver plates and a red LED.
A couple years later, when Philips was trying to get their electronics into Pacific Stereo, we were gifted a high end system in our Chicago (IL/WI/TX/GA) region. We sold lots of Philips turntables. We didn't carry the other electronics. The system was offered in a sales contest for Sept - Dec '78 season. Happily, I won the system! I wasn't fond of the current (22) GA-877 Philips turntable included, so I returned it to stock for credit and replaced it with a Sony PSX-6 turntable, which also had red LED's with touch controls. Everyone scoffed at this system, until I played it for them. The power amp was 500W RMS @ 8 ohm. With an Ortofon MC-20 and Teac 3300, it ROCKED!
I still have the speakers, which are currently driven by an Onkyo 5.1 receiver on my #3 surround system. I have replaced the drivers. 12" woofers, dome tweeters and midrange.
photo from OakTree Vintage
I bought a GA 212 out of the PS store in Carlsbad in 1978 as a gift to the family I lived with to finish high school. Either it was still current or maybe a close out?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
It was definitely not current at that point. GA-312 may have been the current model early in '78. Late '78 saw the "77" series 877, 777, etc. If yours was open, it was likely something the service department repaired, and then they sold as a "demo."
surteess
Senior Member
Am I right in when you talk about tracking & skating forces, would both of these be better with a linear turntable - skating could not be altered in this case as it is set by feedback sensing which in-turn allows the arm to move forward/backward?.
I'd say yes. I had a Technics SL-7 which worked incredibly well, but needed a special cartridge, so couldn't have done CD-4. But Revox did make a Linear tracking turntable which could take a standard cartridge, so with low capacitance cable I would have thought it would be good for CD-4.
Doug G.
2K Club - QQ Super Nova
There is no skating force with a linear arm. Skating force is a function of a pivoting arm with an offset headshell.
Doug
Doug
Thank You everyone for your input here.......:sun
Quad901
Member
To qualify to be a quad turntable, it must have Low capacitance wiring and anti-skating scale with CD-4 marking. The Dual 1245 meets these requirements.
