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Converting Turntable to SQ?

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colinbc

New member
Joined
Jul 26, 2010
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2
Location
Austin, TX
Hello,

I'm new here and I wanted to know how possible it is to convert a normal stereo turntable to play Stereo Quadraphonic records in 4-channel sound. Right now I have a Stanton STR8-100 with a normal stereo cartridge, and I don't really want to go around looking for an old SQ Turntable... Are there still SQ cartridges available? What kind of decoder would I need?

Any help here would be appreciated...
 

Bob Romano

Administrator
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Since 2002/2003
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Apr 26, 2002
Messages
4,655
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Viva Las Vegas
Hello,

I'm new here and I wanted to know how possible it is to convert a normal stereo turntable to play Stereo Quadraphonic records in 4-channel sound. Right now I have a Stanton STR8-100 with a normal stereo cartridge, and I don't really want to go around looking for an old SQ Turntable... Are there still SQ cartridges available? What kind of decoder would I need?

Any help here would be appreciated...
SQ records will play on any stereo turntable. They need to played through an SQ decoder like a Tate (big $$$$) or the like - or they can be recorded into your computer and run through a script using Adobe Audition to separate out the front from the rear.

Check out this thread for more details..
https://www.quadraphonicquad.com/forums/showthread.php?10456-A-new-SQ-method!!!&highlight=SQ+adobe
 

Bob Romano

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Absolutely... however like anything - the better the cartridge the better the result but I have a Shure SC35C and an Ortofon Concorde (both relatively cheap $$) that work just fine. I also have an Audio Technica AT15Sa that works great for both SQ and QS as well as CD4. Your biggest hurdle is going to be decoding the SQ signal from your records.
 

Doug G.

1K Club - QQ Shooting Star
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Jul 8, 2007
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Location
Rochester, Minnesota
The only quad LP format that requires a special cartridge having a frequency response and separation up to 45kHz is CD-4. The wiring in the turntable must then be of low enough capacitance so the high frequencies from the cartridge are not attenuated. These two things are really the only difference between a stereo and quad turntable. Any of the matrix formats, of which SQ is one, play fine using regular stereo equipment.

This is because the matrix formats are all recorded and pressed with frequiencies all in the audible range.

As Bob said, your biggest concern will be how to successfully decode SQ, not how to retrieve it from records.

I have a Sony SQD-2050 and, although it may not be as good as a Tate, it does just fine creating a convincing quad soundfield.

Doug
 

MidiMagic

Senior Member
Joined
Jul 5, 2010
Messages
298
I got TWO SQ decoders on eBay a few years ago for a pittance. The shipping was more than the unit in each case. One is a Metrotec SQ/EV decoder, and the other one is in a Sylvania receiver. They are out there.
 

MidiMagic

Senior Member
Joined
Jul 5, 2010
Messages
298
Is the Metrotec a straight decoder? Is there any logic involved?

Thanks,
Doug
No logic. But it has 4 settings.

The SQ setting is the basic 10-40 blend decoder.

The EV setting is close to EV, but just blends the back SQ channels 80 percent instead of providing the EV back channels.

The Synthesized Quad setting is (amazingly) the EV Universal decoder - almost a year before EV had it out.

The 4th position is unlabeled. I found that I could easily modify it with an unused switch pole in the pushbutton assembly to give the SQ 4 corners without blend.

The Sylvania has a choice of SQ front back logic or SQ 10-40. I don't use it anymore because the controls keep getting noisy again after I clean them.
 

DJWORM

New member
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Jul 3, 2019
Messages
2
Location
PA
I too am wondering what I need to do to transform my stereo turntable into Quad. I just acquired the following: Phase Linear 8000 linear tracking turntable, Pioneer QC 800 pre amp, Pioneer QM 800a power amp. I have a line on a Ortofon SL 15 Q cartridge which is good for CD 4. What is necessary to install it on the PL 8000 aside from normal stylus set up to enable Quad?
 

tcdriver

Well-known Member
Since 2002/2003
Joined
Aug 2, 2002
Messages
182
Location
Valley of Heart's Delight
I too am wondering what I need to do to transform my stereo turntable into Quad. I just acquired the following: Phase Linear 8000 linear tracking turntable, Pioneer QC 800 pre amp, Pioneer QM 800a power amp. I have a line on a Ortofon SL 15 Q cartridge which is good for CD 4. What is necessary to install it on the PL 8000 aside from normal stylus set up to enable Quad?
There are/were three major quadraphonic era systems: SQ, QS and CD-4. The SQ and QS systems can use any ordinary two-channel stereo cartridge, so, they are the easiest to set up. A good QS / SQ decoder is needed to play these formats. The Involve Audio's Surround Master V2 is an excellent modern QS / SQ decoder. A search on this website will turn up a lot of information on this unit.

----------------------------------------------------------CD-4 ---------------------------------------------------------------------

To successfully play a CD-4 (aka Quadradisc) disc, you will need the following:


1. CD-4 encoded record. It should say CD-4 or Quadradisc on the cover.

2. CD-4 demodulator, either stand alone or built into a receiver, preamp or integrated amplifier.

3. CD-4 capable phono cartridge. i.e. capable of frequency response to 45kHz. The carrier frequency, 30kHz., is frequency modulated from 20kHz. to 45kHz. Conical or elliptical shaped diamonds are not suitable for frequency response to 45kHz. The Shibata diamond tip was introduced specifically to play back the high frequencies found on CD-4 records. Other stylus shapes, “Quadrahedral”, “4 Dimensional”, “mico-ridge”, “line contact”, etc. were also developed for CD-4 disc use.

4. Turntable with low capacitance arm wiring and low capacitance interconnects. The total capacitance from headshell to the end of the cable that plugs into the CD-4 capable phono inputs should be < 100pF.

Some examples of CD-4 (Quadradisc) records:
CD-4 Records small(800x627).jpg
 
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