CD-4 - The thin line between success and failure, but still in the fight!

[Marcsten]

CD-4 advice is like asking how long is a piece of string? There's lots of answers. To make CD-4 work I am convinced that 90% is the cartridge and cables. If you are sure your table has low cap leads then the cart is the most important thing. I am running a Lyra Kleos moving coil cart. It aint cheap at about $5k but I love the smooth sound and it rocks CD-4. I have an old Marantz CD-400B and it works fine. Not great in terms of sound but the separation with this cart is super discrete. So if you are running an M24H, which I ran for many years you are missing out. The new gen of carts track so much better and makes those trashy sounding CD-4s clear!! Also, clean your CD-4s, but that is another thread...

 

[kfbkfb]

Could be helpful to have a "clearinghouse" for info about CD-4 hardware (primarily cartridges that work well even with the early CD-4 discs [~1972]), listed by name.


(I'm interested in specifics about how particular carts work w/CD-4 - good on outer grooves, poor on inner grooves, good on CD-4s that are cut at a low level but distort on CD-4s that are cut at a high level etc.)


Kirk Bayne

 

[edisonbaggins]

I'd love to hear about those carts that handle everything pretty well...

 

[edisonbaggins]

Radar light active, even with a stereo stylus

 

[edisonbaggins]

Anyone know what I should ground the 4DD-10 to?
It creates a hell of a hum! Only has a 2-prong plug, so I'll have to pigtail a wire off its ground screw.
Thanks!

 

[fredblue]

Anyone know what I should ground the 4DD-10 to?
It creates a hell of a hum! Only has a 2-prong plug, so I'll have to pigtail a wire off its ground screw.
Thanks!

if you attach the ground cable from your turntable to any other preamp you have connected to the mains power you should be fine, you then shouldn't have to earth the demodulator as well

 

[fredblue]

Radar light active, even with a stereo stylus
View attachment 81720

that's somewhat encouraging, maybe but lighting that light is only step 1, i would say.

what happens when you playback a test disc with a 30kHz pilot tone? does it meep or does it squawk?

 

[J. PUPSTER]

It creates a hell of a hum!

 

[edisonbaggins]

if you attach the ground cable from your turntable to any other preamp you have connected to the mains power you should be fine, you then shouldn't have to earth the demodulator as well

TT ground is presently connected to the preamp ground screw. Interestingly, the preamp only has a 2 prong plug!
Guess I'll try finding a good ground point on the amp or pre/pro...

 

[furui_suterioo]

Radar light active, even with a stereo stylus
View attachment 81720

I have this demodulator, the radar light comes on with any signal above 6khz, which is fine for cd-4 but necessitates switching into 2ch direct mode for stereo records, unless of course you want to hear it try and demodulate those.

 

[furui_suterioo]

I want to make it abundantly clear, that I have had some success with CD-4 (quadradisc.) But recently much more failure, primarily due to two things:

1- sandpaper effect &
2- issues with old 70's era gear (hum)

When CD-4 works well, the results can be amazingly great. Very discrete mixes brought to life. But let's not fool ourselves, CD-4 is a DEAD format for all practical purposes. I'm not aware of a single bit of hardware that supports/functions with it since the 70's (I'm sure others will correct me if I'm wrong here!)
Heck, even in the whole of this very niche QQ surround/Quad forum of supposedly over 10,000 members; I wouldn't be surprised if there're only a few dozen actively listening directly to CD-4 albums.

So when it comes to support for hardware, a grand search must be undertaken for places like qrxrestore etc. that still have the knowledge and abilities to do the job right.

Long before I started working towards a CD-4 system of my own, I was a non-member lurker here taking in the knowledge the forum offered. And once I took the plunge and got into the forum, I found friends with similar interests to help me along and further my education. To date, I believe I've pretty much read most of what's offered here for CD-4 information. But that doesn't necessarily translate to a golden ticket of success. The struggle must be endured to get there.

It took me till my 3rd try at a turntable before I found one I liked and fit the bill. It's a Technics SL1200MK7. Then I had to find the right carts. I started with an AT440MLb and that did a decent job, but I felt a little more separation could be had, so I changed over to an older AT15S (Shibata) which I've been happy with, especially for CD-4. I still have a new AT VM740ML (MicroLine) to give a try; however that's one area I don't relish, is changing out carts and having to adjust/realign each time.

I've actively been buying CD-4 albums (primarily through sellers on discogs) in NM or better condition which is another added expense. Of course that's all part of the cost of the hobby, I don't really mind that, the hunt is an enjoyable aspect for me. I had a nice little stack built up and cleaned ready to go and Demodulate/Convert to digital also; when I discovered my QRX-8001 had a couple of new issues. First the Left Rear channel is cutting in and out, but I could still rip/convert the LP. Then I discovered it also developed some nasty hums (both a lower level and some higher toned hums.) Well the Sansui had already been gone over a couple years ago by qrxrestore along with the Holy Grail alignment; I can tell you, along with the initial cost of the Sansui and the qrxrestore work (along with shipping costs for the beast) it ain't cheap folks! OK, so I'm not ready to send this back again to qrxrestore for more work. I can afford it just fine, I just hate all the tearing down of my system, packing up and shipping out, etc. etc.

So I decided to look for a stand alone Demodulator while I sit on the Sansui issue some more and chew on it. I found a nice Marantz CD-400B that was listed on eBay as a NOS, and it looked every bit of a new in box type unit. So I bid on it and got it for a measly $198 with shipping. Not bad, but I knew full well that even though it looked new in box, who knows what it's really been through and also that for a nearly 50 year piece of gear that doesn't count for much. But for that money, and feeling somewhat wanting of something right away I bit on it. Well it turns out it works pretty well except it too has a mild low level hum. I thought at first, after doing some research, and hearing some vocalization in the hum perhaps I have a ground loop issue. But, after doing some other testing on my setup of:

A: Recording a regular LP through a MOTU UltraLite mk4 with just my Technics SL1200MK7 and Rotel preamp, no hum!
B: Recording a QS LP through a MOTU UltraLite mk4 with my Technics SL1200MK7 and through my Surround Master v2 for Quad, and again no hum!

All that I've talked about here on the open forum is only a tiny tip of the ice-berg as to conversations I've had with very experienced and knowledgeable folks in private messages about my CD-4/Quad issues. They all have been very valuable friends and supportive in trying their best to help me out. I feel I am sooo very close to have it all working as it should, only if the old gear would hold up. But that's the rub right!

We're now working with the idea that the hum is possibly caused (the Marantz Demod.) by either a dry joint or a failing electrolytic capacitor. None of that means much to me, as I don't have experience in working on electronics, and have no interest in learning at my advanced age. So now where does that leave me? I guess I find someone that can work on such things, kindly offer to have a go at fixing my limping Marantz; or I find another old 70's piece of Quad gear to throw money at

From my perspective CD-4 can be a beautiful lady waiting to be aurally caressed, or as more often, it appears to me at least, a cold hearted soul crushing Bitch!
Yes I'm still in the fight, but my time is running short if I'm going to fully realize this dream.

Here's a sample of the Marantz hum (the Marantz was turned on at about 27 sec. into this one min. mp3 sample) and boosted about 30 dbs so you can hear the hum better.

I know how it is investing in cd-4, I have a big investment in strain gauge carts/styli and expensive oddball SH-3480 demodulator which has low output in one channel, so they are just sitting. I can either buy another expensive demodulator such as a technics Sh400 or Panasonic se405, or try to persuade a shop to attempt a fix the SH-3480. Until then, it's the AT440MLB with the JVC 4DD-10 which works well enough. I will not give up on trying to get the strain gauge system going though, it just needs more money thrown at it.

 

[J. PUPSTER]

I know how it is investing in cd-4, I have a big investment in strain gauge carts/styli and expensive oddball SH-3480 demodulator which has low output in one channel, so they are just sitting. I can either buy another expensive demodulator such as a technics Sh400 or Panasonic se405, or try to persuade a shop to attempt a fix the SH-3480. Until then, it's the AT440MLB with the JVC 4DD-10 which works well enough. I will not give up on trying to get the strain gauge system going though, it just needs more money thrown at it.

@sjcorne (that lucky Dog!) has a similar setup with the SH-400 and a strain gauge cart and swears by it. Now if I can just find me one of those SH-400's (I rarely see one even come up for sale, only manuals LOL)

 

[DuncanS]

View attachment 81727

That picture should be banned! along with all Snakes & garden gnomes

 

[J. PUPSTER]

That picture should be banned! along with all Snakes & garden gnomes

It's the Mighty Ho Ho Ho Hummers

 

[DuncanS]

It's the Mighty Ho Ho Ho Hummers

Were is a Howitzer when you need one!

 

[fizzywiggs41]

I was going through some olde CD-4 info notes (CD-FORUM) and came across this rather blurry copy of JVC'S latest and greatest for Dec 76. At first I thought this must be the Preamp , but no its the demodulator.
It's hard to read but I finally deciphered what the title of this unit says :

CD4- 50 DISC DEMODULATOR


SO ...did anyone bother to purchase one of these back in the late 70's ?

 

[edisonbaggins]

So... my JVC 4DD-10 might be bad...
Connecting my TT (Pioneer PL-12D) straight to the phono input of the demod:
Stereo (from a stereo source) is totally silent.
CD-4 (from the stereo source) sounds BAAAAAADDD.

It occurs to me that I should check how a CD-4 source sounds?

Side note: if I connect the TT's ground wire to the 4DD-10's ground peg doodad, it creates MORE hum. If I leave it dangling, there is hum, but much less. Not pleasant though.

 

[fizzywiggs41]

So... my JVC 4DD-10 might be bad...
Connecting my TT (Pioneer PL-12D) straight to the phono input of the demod:
Stereo (from a stereo source) is totally silent.
CD-4 (from the stereo source) sounds BAAAAAADDD.

It occurs to me that I should check how a CD-4 source sounds?

Side note: if I connect the TT's ground wire to the 4DD-10's ground peg doodad, it creates MORE hum. If I leave it dangling, there is hum, but much less. Not pleasant though.

Yep.

Unfortunately these things happen. You might try a reliable electronics audio repair shop , as it may be something minor that can be fixed likety-split.

But before that unplug it... open it up.... and take a peek for your own piece of mind.

 

[edisonbaggins]

Yep.

Unfortunately these things happen. You might try a reliable electronics audio repair shop , as it may be something minor that can be fixed likety-split.

But before that unplug it... open it up.... and take a peek for your own piece of mind.

It was a freebie, FWIW.
I have been known to achieve some minor repairs. Would be fun to see inside [I'm sure there's a dirty joke there, somewhere, somehow]...

 

[J. PUPSTER]

Yep.

Unfortunately these things happen. You might try a reliable electronics audio repair shop , as it may be something minor that can be fixed likety-split.

But before that unplug it... open it up.... and take a peek for your own piece of mind.

I'm needing to find a reliable local electronics repair dude, but starting to think I've missed a humgeld payment to the Hum Gods