Have I been doing cd-4 wrong all this time?

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ArmyOfQuad

2K Club - QQ Super Nova
Since 2002/2003
Joined
Apr 22, 2002
Messages
2,320
Location
Attleboro, MA
Before you say no way, your past conversions sounded great, lets just throw out everything we know, because I think holding onto past knowns has thrown me off for years now.

My cd4 setup for years had been Cai's old setup, a mitsubishi linear tracking turntable with signet cartridge. When I got this pairing, it seemed to be a magic bullet, and away I went converting Black Sabbath - Paranoid and Hugo Montenegro - Love Theme From the Godfather with results that had been described as the best sounding cd4 conversions from US vinyl. (or "well, it sounds.....okay.....but your demodulator may need work" from a guy who's name starts with Q and ends with uadbob)

But, I wonder....have I been calibrating correctly?

The marantz cd4 calibration record that is supposed to pair with the cd400 states that you turn the knob fully clockwise, use the 30kHz tone which will sound distorted, and go counter clockwise until it isn't distorted. However....what is distorted/not distorted? That is, how should the tone sound when it isn't distorted?

Before you say, not distorted, duh....the thing is, I don't know what we have for a tone. Is it a pure sine wav? Because, up until now, I've calibrated for it to sound like a buzzy kinda wave, maybe sawtooth like. Turning the knob had me going back and forth between sandpapery breakup, and consistent buzz wave, with me thinking that that is what it sounds like. But, after going through many trials and failures, I finally broke down and got the one cart that ever gave me magic bullet results retipped, since I can't find a replacement stylus anymore. And it was retipped with a line contact tip, which should be within spec. But....I didn't get those magic bullet results, and like everything else I've been trying over the past few years while Japanese imports sit on the to do pile collecting dust, my results have be going.....eh.....well.....maybe? I think that sounds like it did? Er....no....NO...FUCK THIS ALL, I FUCKING HATE FUCKING CD4 FUCK FUCK......eh, you get the idea.

But, I don't know that I've been turning the knob the right way for distortion to end. I think I've been going counterclockwise, and turning clockwise, going through the breakup spot, until I get the sawtooth wave, which is the opposite of what the instructions say when I double checked that today. So, this time I started clockwise, had my buzz wave, went through the sandpaper, and ended in pure sine wave territory.....which had me going....no.....no....I couldn't have been doing this wrong all those years and gotten the results I did.

Did I?

Well, the results seem to be good. I'm still uncertain, all cd4 confidence I once had years ago is long gone at this point, but....I think I was doing it wrong and somehow got lucky with records that decode great even with bad calibration, and EQing to correct the dulled results that come from turning too far clockwise.

Or....I'm wrong now, the retip isn't as good as the original tip (plus I've decided I hate linear tracking and have gone to a pivot arm...which this morning I think I improved things slightly by going with a stevenson alignment since the most problematic parts of the playback have been at inner grooves), and the rotations are reversed to take into consideration the control is on the back, and you are likely going to reach back from the front.


ARRRGGGHHH.....I don't seem to know anything anymore, and am at a point where I need feedback from the experts, since clearly I am not one of them anymore in this department.....or I was.....or, I need to relearn or.....ugh....ok, I'm rambling at this point, time for the other cd4 gurus out there to chime in.
 
I give up. cd4 has brought me nothing but disappointment, misery, frustration, and wasted money....it can't work adequately. Period.
 
I feel your pain. The frustrating thing about CD-4 is getting . . . so . . . close to remarkable sound, and then something is off.

I was hoping the Lou Dorren project would right some of these wrongs. Hope is getting pretty slim these days . . .
 
. . . so . . . close to remarkable sound
Pursuing Quad is mostly about the mix, not the quality of the recording.

Adding to the above, using old equipment is always complicated.

I wish for a software solution for CD-4, hopefully based of half-speed playing.
 
Pursuing quad listening is about the mix. Allowing quad preservation to rule your life is about being miserable about years of shitty quality control and awful technology, with the exception of the quad reel...which even that has it's issues.

Ugh....maybe I need to play with more equipment....anyone in the bay area have some spare demodulators, high end cartridges, and turntables that we can play around with and try to find a good pairing for once and for all?
 
This time (been 10 years)It took me about 6 weeks to get a cart and headshell matched up and working. I have been playing with 3 carts and 3 headshells, an AT15 AT20 and LC needle AT440. It takes time and work to get one to match up and get it aligned. I finally have the AT15 dialed in perfect. That was after I had the AT20 up and recording for a month. Something was just a tad off, starting all again. It would have a tiny breakup on one channel on some lps. Plus was not plowing thru the RCAs well. The tough one is to get the cart to play thru tough lps. that is tricky. but it can happen. It does take work. The first hint you dialed it in will be being able to play a RCA cd4 and it sounds good!!! A huge hint is the overhang must be correct. Pull the cart way back usually to almost the back on most tables. Cut a piece of paper to however many millimeters you need and check that measurement.
The demod makes a damn big difference. The JVC were the best by miles and miles. good conversion here real soon.
 
With the use of an alignment print out tool, and the zooming on my phone's camera, I've been alignign things precisely. But, I can't get it at all.

As I mentioned, I got the best luck with a Stevenson alignment, which favors the inner grooves. I get the most problems on those inner grooves.


But, at this point, I'm looking for a good setup to get good recordings. if someone else has it, I've got a pile of rare Japanese stuff that needs recording.


Do you own copies of Godspell and Captain and Tennille - Love Will Keep Us Together? If so, could you send me recordings of the last cuts on side 1 of both? If you can play those back cleanly, we should get some rare cd4 records onto that setup for preservation.
 
Ok, for now I think the answer is....no, I've been doing it right. The pure tone on the test tone results in a more open high end, but more distortion on the decode. My conversions sound more open on the top end because I've never shied away from tweaking the EQ, even if it means bringing out a bit more record noise along with EQing it to sound where I think it needs to be. Calibrating the demodulator with the methods I've always used can bring results I'm used to hearing on certain records, and I managed to luck out with my selections for early cd4 conversions. Cai used to always comment that most American pressed cd4s didn't make the cut to be converted, and I think even with the best of circumstances with what is available to me right now, there's no avoiding the sibilence on the last cut of side 1 of Captain and Tennille. But....with things calibrated to ideal conditions, maybe I can try to EQ it to something listenable, I dunno, the record is a loaner so I'm going to record it in with ideal conditions anyways. I've also convinced myself that software decoding with 96kHz files should be possible, if someone with the knowhow took on the project. I also think I've been a bit tough on the CD, the science behind the nyquist theorem is sound, CD can accurately go up to 22.05 kHz, which is adequate for the human hearing range....but it certainly won't have me swearing off vinyl or hi-res.

This has been an educational experience beyond quad.
 
One little update, in case anyone is ever reading this for tips on what to do....or better yet tips on what not to do. After a day of looking at several cd4 records, I noticed something quite obvious I never noticed before. They have more dead space on the inner grooves than standard LPs, which makes the Stevenson alignment a bad choice since that aligns the null point right at a spot where there is no music. Stick with the baerwald.
 
I get good results with my AT440MLa cartridge and stylus. If you have splatter, then more than likely the stylus is failing to track, or is just skating over the fine subcarrier modulations, like a car tire on a washboard dirt road. Get that right, and CD-4 troubles just melt away.
 
I get good results with my AT440MLa cartridge and stylus.

I just put one of those on a Sony PS-X75 last night. Either my fumbling 54 year old fingers guided by lousy eyes managed to get everything perfect with just a screwdriver and the alignment guide on the reverse of the turntable mat or it's one hell of a forgiving cartridge. I had a clean carrier lock all the way to the end of side one of "No Secrets" and also enjoyed what I heard on some non-CD-4 vinyl.

It replaced a Shure/Radio Shack RXT5 that's been on that deck since circa 1986. That cartridge and stylus are still just fine, but I was starting to get worried about the squishy parts deteriorating and figured another CD-4 option couldn't hurt.

Only complaint: I hesitated to buy the cartridge at ~$150, then got annoyed when Amazon raised the price to almost $200. After a week or so of hoping it would drop back down, I went ahead and ordered one via my Prime account. It took three days rather than two to arrive (to be fair, a lot of Prime orders actually arrive the next day) and...the price as of yesterday is down below $150 again. I wrote Amazon a whine-o-gram and they gave me back $13 and change. Better than nothing, I guess.
 
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Yes, the AT440MLa is a good cartridge. It uses a microline stylus which is an improvement on the Shibata type. Otherwise known as a line contact stylus, they last too, I used one stylus for nearly 10 years, possibly longer. I am just starting on my second one. I am very pleased with it's performance.
 
I used the AT440ML Stylus in the Audio Technica AT155LC cartridge for years with GREAT results. However now I use an AT20SS, but my straight tonearm and built to CD-4 specs BIC 1000 turntable works better than any I've heard. (of course it comes with low cap. wiring, a necessity for CD-4).
Never knew of any linear tracking turntables with CD-4 wiring, but obviously you've found one. I just don't care for "S" tonearms after hearing the BIC.


Yes, the AT440MLa is a good cartridge. It uses a microline stylus which is an improvement on the Shibata type. Otherwise known as a line contact stylus, they last too, I used one stylus for nearly 10 years, possibly longer. I am just starting on my second one. I am very pleased with it's performance.
 
B&O had a few LT tables in the mid 70s capable of CD-4, some had the demod built right into the table, maybe solving the capacitance issue. I'm gonna try my B&O TX(1983) once I get it rehabbed.
 
I wonder who did the quad to DVD of the Japanese CD-4, Marvin Gaye - "What's Going On".

They definitely figured out and ironed out the bumps in the CD-4 road for that one. Just stunningly beautiful.

But then, The Jackson 5, and Diana Ross & the Supremes Greatest Hits CD-4s are also total winners.

Those darn Japanese LP pressings I tell ya.
 
I was doing it wrong all along. But they came out right. I hate CD4. Kinda.
AOQ, are those your babies? They are my top three conversions from CD-4. But then again what would one expect from Japanese pressings, exclusive (quad material) program, top rate musical material. Next in line is the Temps "All Directions" - now if this is also your investment of time and resources, then you do get into the gates of heaven. I mean your are already in the quad HOF no doubt.

What wonderful gifts to the world, I hope someone else forked out the cash and let you spend the time (and frustration) to get them as right as you could st the time.

Btw, what did you learn later that is an indication you did it all wrong?
 
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