CD-4 adjustment question

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gvl_guy

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My old CD-4 demodulator didn't have a carrier level adjustment, so I didn't need to do that. I just had to adjust front/rear separation for both left and right. Easy peasy.

But my Sansui QRX-7001 has this adjustment and it seems to do little as I turn the knob.

If I have the knob turned all the way to the left I definitely notice it's incorrect. But as I start to turn it to the right, once things start sounding okay, turning it any further to the right doesn't seem to make any difference. And it starts to sound correct only about a quarter of a turn from left to right into the adjustment.

My question is, do I turn this dial to the right just until everything sounds okay? Or do I turn it further? Does it really make any difference?

Also, I have two different CD4 cartridges. Shure and a JVC. Do I need to readjust everything when I switch to the other cartridge?

I appreciate your help! Good morning
 

soesbeout

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My old CD-4 demodulator didn't have a carrier level adjustment, so I didn't need to do that. I just had to adjust front/rear separation for both left and right. Easy peasy.

But my Sansui QRX-7001 has this adjustment and it seems to do little as I turn the knob.

If I have the knob turned all the way to the left I definitely notice it's incorrect. But as I start to turn it to the right, once things start sounding okay, turning it any further to the right doesn't seem to make any difference. And it starts to sound correct only about a quarter of a turn from left to right into the adjustment.

My question is, do I turn this dial to the right just until everything sounds okay? Or do I turn it further? Does it really make any difference?

Also, I have two different CD4 cartridges. Shure and a JVC. Do I need to readjust everything when I switch to the other cartridge?

I appreciate your help! Good morning
 

soesbeout

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Messages
293
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My QRX 7500 has 3 also the carrier level was adjusted on 1 particular track on the Sansui adjustment record.
 

gvl_guy

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Messages
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Location
Greenville, SC
Should be similar to this.
View attachment 51685
Enjoy CD-4! It is way challenging but when it works it is very satisfying.
Ah ha! So, according to this, I turn the carrier level adjustment all the way to the right. I play the tone, then turn it counter clockwise until I don't hear the tone anymore. Then just back it off a bit. Perfect. Thank you!
 

gvl_guy

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I'll hopefully be diving into the CD-4 experience in the next couple months with my QRX-8001 also; any advice on the procedure and adjustment discs would be appreciated- thanks!
I have 3 discs. One came with my Pioneer receiver many years ago. 7" It works, but sounds a little like sandpaper. (I guess it doesn't have to sound perfect for the tones to work.) It's 45rpm.

I also bought a new-old-stock JVC demodulator that wouldn't power on and I sent it out for repair. It came with a disc, too. Also 7" and 45rpm

Last, I purchased a CD-4 demonstration disc with music from the WEA group that also included the tones. It's 33 1/3rpm and an LP.

There are a bunch out there. Find one on eBay. I wouldn't spend more than about $8-10 on one. Some people call them "rare," but unless you have a demodulator, they are pretty worthless. 🙂
 

Sonik Wiz

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I'll hopefully be diving into the CD-4 experience in the next couple months with my QRX-8001 also; any advice on the procedure and adjustment discs would be appreciated- thanks!
Along with proufo's info, give a listen to that CD-4 set up record I sent you, even if it's just in stereo for the moment. It starts off with slow & boring narrative but it turns very useful, explaining step by step how to adjust & what it should sound like.
 

J. PUPSTER

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Along with proufo's info, give a listen to that CD-4 set up record I sent you, even if it's just in stereo for the moment. It starts off with slow & boring narrative but it turns very useful, explaining step by step how to adjust & what it should sound like.
I haven’t forgotten; and much thanks 😊
 

fredblue

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Along with proufo's info, give a listen to that CD-4 set up record I sent you, even if it's just in stereo for the moment. It starts off with slow & boring narrative but it turns very useful, explaining step by step how to adjust & what it should sound like.
which record is that?
 

Sonik Wiz

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which record is that?
The record was purchased through a former quad newsletter distributor called 4 Quad. It's the only CD-4 test record I know of with the guiding hand of Lou Dorren himself, and indeed a special collaberation with Brad Miller on the Sound Bird label. I can find some Sound Bird info on Discogs but this is so rare it's not even there. So at least there's this:


It even has bands to check automatic CD-4 switching, side front to back sweeps and rumble test.

Edit: Good thing I have one more!
 
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sjcorne

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Along with proufo's info, give a listen to that CD-4 set up record I sent you, even if it's just in stereo for the moment. It starts off with slow & boring narrative but it turns very useful, explaining step by step how to adjust & what it should sound like.
On one of my set-up LPs (I think Project 3's Popular Science?), the announcer triumphantly states "welcome to the wonderful world of CD-4!" after the tones end.
 

Sonik Wiz

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Yeah, Easy Peasy right? 😬
My 1st CD-4 Demodulator was a Sansui stand alone unit & the 2nd one was a large removable plug in cartridge that inserted into my Kenwood 9940 receiver. Both had carrier level & separation adjustments & they came with pretty minimal set up records. I have never been too obsessive over cart/TT set ups, but despite that I've also had really good luck setting up & playing back CD-4.

I have dozens of CD-4 records but even in the day the surround results never impressed me. I don't think this is expressly due to any technical flaw in CD-4 but the artists chosen & the unimaginative skill of many mixes.

I mean Frank Zappa, The Doors, Jethro Tull... this should be some dynamic exciting stuff. Most of the mixes are just plenty tame & fail to excite. Now there are many hyped up demo sampler discs that go just the other direction with swirling instruments, crazy sound FX, instruments in each corner. In other words too much of a good thing. I guess it's like Spinal Tap might say: "It's such a fine line between stupid and clever."

Edit: In rference to comment about artist chosen.... I don't mean Tull, Doors, Zappa. I am mainly thinking of all the Henry Mancini, The Carpenters, Bread, Art Blakeley etc easy listening stuff out there. And there's a lot of it on CD-4.All those artists I just mentioned I respect them & have very much enjoyed their talents. What I'm getting at is this is not the type of music that really shows off a discrete format, tape or disc.
 
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MidiMagic

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I was never impressed with CD-4 because it had the side imaging problem.
 
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