Wow - Quadraphonic Sound

[Stubies]

Who remembers Quadraphonics?

I just purchased an old Rotel TT, here is something from the manual:

http://i1176.photobucket.com/albums/x321/stuarttill/4channel.jpg


And look at what is on ebay just now: Vintage JVC 4DD-5 Disc Demodulator CD-4 Quad 4-channel Turntable Phono Pre Amp
http://i1176.photobucket.com/albums/x321/stuarttill/cd4front.jpg
http://i1176.photobucket.com/albums/x321/stuarttill/Capture.jpg
http://www.ebay.com/itm/Vintage-JVC-4DD-5-Disc-Demodulator-CD-4-Quad-4-channel-Turntable-Phono-Pre-Amp-/221179673101?pt=US_Home_Audio_Amplifiers_Preamps&hash=item337f55fa0d


So all i need now, is a 4 channel cartridge... !

I wonder how they 'demodulated' the sound from the turntable to get 4 channels....? :scratch:

[Roy S]

I used to have a pair of quadraphonic headphones, had to lie down when I wore them otherwise I'd have snapped by neck :lol:

[Rare Bird]

I have a Sony SQD2020 & SQD2050 decoder & recently picked up an Akai CR80DSS Quad 8 Track machine

[Wakefield Turntables]

I always collect Quadraphonic vinyl when I see it just for the hell of it, I have several albums now salvaged from various charity shops. :lol:

[twotone]

I've Roberta Flack's Killing Me Softly on Quadra Disc, UK first press I think, if anyone is interested @ £9 posted.

Tony

[PaulStewart]

I wonder how they 'demodulated' the sound from the turntable to get 4 channels....? :scratch:

Hi Stuart,

Way, way back in the day I was Tech Liaison Officer at JVC (UK), and I still have a collection of various CD-4 bits plus quite a few discs, I did some CD-4 remixes as well. The system works by having a high frequency carrier on the disc that contains the difference signal between front and rear. This is picked up by the cartridge, which must have a Shibata or similar profile to enable it resolve these beyond 20kHz signals. Also, the whole low noise vinyl, half speed master thing (they needed to half speed master to resolve the carrier as the cutting heads could not go that high), came from CD-4 as did line contact styli, so as well as being the best vinyl based quad system, it improved stereo reproduction too. These days you can do it all in software from the digital stream, but back then it was quite astounding. We did some cutting edge stuff, that I have never heard bettered.

[Rare Bird]

I'm always on the look out for JVC 'VR 100' Quad recievers

[dantheman91]

Love my Sansui QEX 5500 now theirs a beast

[Stubies]

Interesting there was such a specialized technical approach. I would not have guessed that there were separate signals embedded in the music!

thanks for the REAL explanation Paul!


Hi Stuart,

Way, way back in the day I was Tech Liaison Officer at JVC (UK), and I still have a collection of various CD-4 bits plus quite a few discs, I did some CD-4 remixes as well. The system works by having a high frequency carrier on the disc that contains the difference signal between front and rear. This is picked up by the cartridge, which must have a Shibata or similar profile to enable it resolve these beyond 20kHz signals. Also, the whole low noise vinyl, half speed master thing (they needed to half speed master to resolve the carrier as the cutting heads could not go that high), came from CD-4 as did line contact styli, so as well as being the best vinyl based quad system, it improved stereo reproduction too. These days you can do it all in software from the digital stream, but back then it was quite astounding. We did some cutting edge stuff, that I have never heard bettered.

[Rare Bird]

Love my Sansui QEX 5500 now theirs a beast

Sansui 'QS1' is a beauty if you ever see one

[The Black Adder]

I remember it,... only just. I had a crown hifi that had it in the 80's.

Crown ey!... Were they any good? The stuff in the 80's was pretty dire as far as I remember. Awful quality, well externally anyway.

[Stubies]

Yea, not just the equipment, everything was dire in the 80s. No memorable cars, music was less memorable too, and everyone wore lots of brown. It was bad!




I remember it,... only just. I had a crown hifi that had it in the 80's.

Crown ey!... Were they any good? The stuff in the 80's was pretty dire as far as I remember. Awful quality, well externally anyway.

[walpurgis]

Yes the eighties were pretty cheap and nasty. Still, at least you had your Filofax handy! :eyebrows:

[The Black Adder]

Yea, not just the equipment, everything was dire in the 80s. No memorable cars, music was less memorable too, and everyone wore lots of brown. It was bad!

Right on brother!

:)

[Rare Bird]

I was at my most active Hi-Fi buying wise in the 80's i can't say i was ever happy with much.