CD-4 demodulator adjustment

Help Support QuadraphonicQuad:

fredblue

2K Club - QQ Super Nova
QQ Supporter
Joined
Mar 30, 2009
Messages
24,272
Location
London, England
Thank you both, Doug and quadsearcher.

To be honest, I didn’t like the idea of placing a screwdriver in the back of a live unit, so I did what quadsearcher suggested...

I put a Quadradisc record on the turntable, disconnected the CD-4 RCA cables, then placed one of them in each of the four inputs. They all hummed, and played independently. I connected them all back, and I’m pleased to say that miraculously, it’s now all working, and I’m experiencing the glory of discrete quadraphonic sound! The Discrete 4 mode on my receiver is working fine.

Interestingly though, the CD-4 adjustment record still doesn’t separate front and rear; could it be that it was just a poor record?

Many thanks for all your help, everyone!
one of the JVC Adjustment 45s (4DE-202) had an issue, which one do you have?
 

RockaMarka88

Member
Joined
Jan 20, 2021
Messages
12
Location
GB
one of the JVC Adjustment 45s (4DE-202) had an issue, which one do you have?
Hi, fredblue.

Yes, my one is 4DE-202.

D1EFA1DA-C3AB-4DE8-864B-6E89ECF46BD2.jpegB4CFA1B0-4E53-4B75-BB23-03F10B708B15.jpeg

So it had an issue? No wonder I couldn’t get any separation! In the end, I just used one of my Quadradisc records!

Many thanks!
 

fredblue

2K Club - QQ Super Nova
QQ Supporter
Joined
Mar 30, 2009
Messages
24,272
Location
London, England
Hi, fredblue.

Yes, my one is 4DE-202.

View attachment 62194View attachment 62195

So it had an issue? No wonder I couldn’t get any separation! In the end, I just used one of my Quadradisc records!

Many thanks!
yes 4DE-202 has the channels lumped together in one of the test tracks so you can chuck it! 😂

tbh my favourite CD-4 setup disc is the Fisher Test & Performance Standard CD-4/SQ LP, i like having separate L&R adjustment tones and some of the demo tracks are hilarious with fun mixes!


F3279E38-8617-49A7-8655-BB877767BF0C.jpeg
 

J. PUPSTER

2K Club - QQ Super Nova
QQ Supporter
Joined
May 30, 2017
Messages
7,659
Location
CALIFORNIA (CENTRAL)
yes 4DE-202 has the channels lumped together in one of the test tracks so you can chuck it! 😂

tbh my favourite CD-4 setup disc is the Fisher Test & Performance Standard CD-4/SQ LP, i like having separate L&R adjustment tones and some of the demo tracks are hilarious with fun mixes!


View attachment 62208
Thanks Freddie, just picked one up for a Jackson :)
 

aludra

Senior Member
QQ Supporter
Since 2002/2003
Joined
Sep 4, 2003
Messages
227
Location
Nashville
Would this defect also be on the Pioneer PQX-1101? On the disc itself it is written in underneath (4DE-202)...Is this a JVC disc with a Pioneer stamp? Thanks for any info.
 

surround.sound.enthusiast

400 Club - QQ All-Star
Joined
Mar 25, 2014
Messages
435
Location
Massachusetts
Glad to hear it all worked out for you RockaMarka88, welcome to the world of CD-4. I hadn't read about the botched JVC calibration disc before. I got lucky that my 4DD-5 came with a different iteration - because it set-up very easily.
 

fredblue

2K Club - QQ Super Nova
QQ Supporter
Joined
Mar 30, 2009
Messages
24,272
Location
London, England
Glad to hear it all worked out for you RockaMarka88, welcome to the world of CD-4. I hadn't read about the botched JVC calibration disc before. I got lucky that my 4DD-5 came with a different iteration - because it set-up very easily.
4DE-205's the other JVC 4DD-5 pack-in adjustment disc that i have and afaik its fine, even if it doesn't have separate warble tones for Left & Right but only L&R simultaneously it seems to be ok for setting up.

there were quite a few of these 7-inch 45rpm CD-4 Setup discs bundled in with demodulators made by the numerous brands doing CD-4 Quad at that time, some appear to be clones of the JVC discs but some have unique material including a couple of examples for the Japanese market i found from manufacturers including Toshiba and Kenwood, which have narration and channel announcements in English by folk with Japanese accents and rather than duplicate Side A's setup tones they have demo music material in 4-channel on the B-Side.
 
Top