Technics CD-4 Cartridges with no audio output

[Circular Vibes]

I really hope you'll be able to put it back into service.

It is a matter of time plus ready cash, My will (and yours) be done! I have actually wondered if I offered one of my SH3480s to an interested tech in exchange for restoring the other for me. I wonder if it would entice anyone enough as a fair trade...

 

[Doug G.]

I have accidentally switched a demodulator to SC with a magnetic cartridge installed and it didn't hurt anything but yeah, I wouldn't recommend it as a general practice.



Doug

 

[Wurly1]

It is a matter of time plus ready cash, My will (and yours) be done! I have actually wondered if I offered one of my SH3480s to an interested tech in exchange for restoring the other for me. I wonder if it would entice anyone enough as a fair trade...

Quite possible.

 

[Wurly1]

I'm happy to report my SS1100-D CD-4 system is now working properly and flawlessly. I draw the schematics of the amplifier section and the CD-4 decoder board. It helped me a lot to pinpoint the many faults my system had.
I must say i'm very impress by the performances of this all transistor CD-4 decoder.
I heard CD-4 system had poor front-back image. Well i must say this one has a very good front-back image.
This decoder does not use PLL circuit (phase-lock loop), instead it uses diode detection much like early FM radios. It make a simpler circuit since the only signal (channel) it tune is the 30khz carrier.

I read in a document explaining in minute details the process of encoding and decoding of CD-4 vinyl records and i found that when cutting the master they produce a 40 microseconds delay between the CD-4 (front minus back) 30khz carrier and the (front plus back) stereo signal. This is to account for the time the decoder need to decode the (front minus back) signal from the 30khz carrier.

In plain english it means the (front minus back) signal is recorded 40 microseconds before the (front plus back) stereo signal creating a delay between the two.
The explanation is simple: In real life, it takes more time to decode a modulated signal than it takes to simply amplify it. (40 microseconds in our case)

So while decoding the CD-4 records it's crucial for the decoding circuit to take exactly 40 microseconds decoding time to restore correct phasing and restore the front / back spatial image. Each transistor introduce it's own delay and therefore each stages can be precisely calculated to match that 40 microseconds target.

Conclusion, new electrolytic capacitors will greatly improve the correct phasing as bad capacitors in some case can introduce phase delay.
The fact the decoder in the SS1100-D is all transistors and have no RF-coils nor RF-transformer is a plus in achieving correct phasing.
Finally, this decoder have no adjustment whatsoever except for the final matrix front/back separation.

 

[Circular Vibes]

Wurly, I am glad you got it going again. I think you will enjoy your SG cartridge as much as I enjoy mine. Is your headshell removable? If it is and you have or get another cartridge, there are 0.5 mil conical tips available to play all your other microgroove records and they are very economical compared to the Shibata tip for CD4. Have a look on Yahoo Auctions Japan as the EPS46STST shows up frequently in quantity.

 

[Wurly1]

Wurly, I am glad you got it going again. I think you will enjoy your SG cartridge as much as I enjoy mine. Is your headshell removable? If it is and you have or get another cartridge, there are 0.5 mil conical tips available to play all your other microgroove records and they are very economical compared to the Shibata tip for CD4. Have a look on Yahoo Auctions Japan as the EPS46STST shows up frequently in quantity.

Thank You Circular Vibes.
I replaced 96 electrolytic capacitors, 4 transistors and 1 IC plus
removed a left-right short circuit wire placed there by some previous
owner and added a jumper to fix a broken trace on the preamp pcb.
So don't worry i enjoy it a lot! It's like brand new.
The "feel" is different than a velocity sensitive magnetic cartridge.
It's like listening with new ears.
I wonder why these SC cartridges did not become more common.

I found 2 new CD-4 LP on Ebay still in shrink wrap. I can't wait to ear
them. Currently i own only 2 used CD-4 LP and they are far from pristine
but they allowed me to discover that anti-skating adjustment is critical
to ensure correct reading of both left and right groove walls 30khz signal.

Thank you for the tip on replacement stylus.
I currently have a yellow stylus marked STEREO and a Red Shibata tip stylus. I got the later new from Voice Of Music in USA for about $58. US
Yes the head shell of my TT is removable which is safer when switching stylus.
I wonder what's the current price for an SC cartridge?
Do you also find shibata tip stylus on Yahoo Auctions Japan?

 

[Circular Vibes]

The Shibata tips command high prices in Japan and even used and damaged ones are sometimes offered. The ones from The Voice Of Music is the cheapest and most reliable that I have found for regular sale. I keep an eye on auctions but ePrey sellers tend to think they are selling Tiffany diamonds when they sell these. As to why they didn't become more common, I can only speculate that people don't tend to like changing thinking, in general of course. They were very popular in Japan for similar units like yours and when they died they either got thrown out or parted as in more current times. There were also many 2 channel SG systems with yellow styli into the 80s which may explain why there are so many replacements available cheaply there. Yahoo Auctions gets them fairly often, sometimes monthly and if you catch it right, the Sg carts and sometimes even sealed genuine Technics Shibata styli can be found at more reasonable costs.
As to CD4 LPs, groove wear and damage like scratches will take away from them but a good wet cleaning does wonders. Japanese sealed Victor label discs can still be found for lesser known titles. I bought 10 different titles from someone who is a member here but I have forgotten his user name. He runs a German quad site you will linked on the home page of QQ. He may still have copies for sale.
I am glad you have done such an amazing amount of restoration and hope you documented it with photos that you might share in another thread later.

 

[Wurly1]

There were also many 2 channel SG systems with yellow styli into the 80s which may explain why there are so many replacements available cheaply there. Yahoo Auctions gets them fairly often, sometimes monthly and if you catch it right, the Sg carts and sometimes even sealed genuine Technics Shibata styli can be found at more reasonable costs.
I bought 10 different titles from someone who is a member here but I have forgotten his user name. He runs a German quad site you will linked on the home page of QQ. He may still have copies for sale.
I am glad you have done such an amazing amount of restoration and hope you documented it with photos that you might share in another thread later.

I will certainly have a look on Yahoo Auctions Japan for cartridges and stylus.
Please if you remember the name of the guy in Germany could you send me a note?
This whole restoration project have been so instructive and good people like you to give some encouragement.
I still have two stretches to go before the end do. I need to replace the power transformer for it to work on 120v instead of 240v and i wish to build a new cabinet as the original is cheap vinyl coated wood imitation (Mac-Tac like). I also have the original big speakers too, same vinyl finish but the wood is so thin it make them sound too boxy. Good for disco, bad for everything else.
I don't know if i will keep them or not.
Should i re-inforce the side panels from inside, build new cabinets same size with better wood or throw them away?
I am torn apart between keeping it original or make it look much better.
"Human decision required" lol

 

[Circular Vibes]

As to the speakers and cabinet, I am out of my league here. Most of not all were made similarly and the Japanese ones suffered badly from being in a damp salty sea air climate. I would try other speakers and see how you like them, paying attention to the original speakers ohms readings. I do not know if they used odd drivers like 16 or 32 ohm or some non standard nonsense. Many of those types of systems in Japan are also sold without the cabinets. Space is at a premium in major cities and it was easier to move a receiver, especially if the turntable or speakers died.
As to the transformer, I am wondering about the line frequency as 240 volts usually means 50 Hertz and 120 usually is 60. Is the turntable on speed? Is the motor DC? Somehow I might have thought it could be an AC synchronous motor that would have the speed tied to line frequency. Most of those units did not include any tape decks which solves the other obvious problem. I have seen many pictures where the space under the cabinet was used to house a reel or cartridge player instead of records.
When I remember the record sellers name I will let you know.

 

[Circular Vibes]

Here is Klaus Hönemann's contact page. He was at one time selling them through his website. I can not be sure he still has any but if he does, he is very nice to deal with. My experience was exemplary. I know he was and possibly still is a member here but I can not find his member name.
quadraphonie.de webpage contact.

Please consider looking around the rest of his site, you will find pictures of quad gear and enthusiasts from Germany, much is uncommon to rare, a word I really don't use often.

 

[Doug G.]

Great site! Although I have seen a picture of the Panasonic FM demodulator before (I think on here, somewhere), it is still about one of the coolest quad things I have ever seen. So is the JVC Memory Meter.

More reminders of what a shame it was that CD-4 was stifled by various factors.

Doug

 

[Doug G.]

As far as why SC/SG cartridges haven't become more popular or didn't, back then (cost is a real factor, these days, I believe people were just so wedded to magnetic cartridges being the ultimate that they ignored any other technology.

The same thing happened with the Micro Acoustic stereo cartridges in spite of the almost universal praise for them.

I really lucked out on getting my EPC 450C II several years ago. The guy who had the eBay auction didn't know what he had. I think he assumed it was just another ceramic cartridge like the Tetrads he had in the auction. 25 bucks for all of them for me.

Doug

 

[Wurly1]

As to the transformer, I am wondering about the line frequency as 240 volts usually means 50 Hertz and 120 usually is 60. Is the turntable on speed? Is the motor DC? Somehow I might have thought it could be an AC synchronous motor that would have the speed tied to line frequency. Most of those units did not include any tape decks which solves the other obvious problem. I have seen many pictures where the space under the cabinet was used to house a reel or cartridge player instead of records.
When I remember the record sellers name I will let you know.

Yes the motor does not turn at the correct speed. I tried to replace both the motor and platter twice but everytime there was something that didn't quite fit. I finally found a suitable turntable, TAYA MP-200 which i believe was another Panasonic/Technics brand. Here is the original TT and the new one.
yes the system is in a cabinet with space for a reel-to-reel or cassette deck.
As for the speakers, on the back of the amplifier it says 8 ohms minimum.
I think i will do away with the original speakers and the original cabinet and place it in a set-top cabinet.

 

[Wurly1]

As far as why SC/SG cartridges haven't become more popular or didn't, back then (cost is a real factor, these days, I believe people were just so wedded to magnetic cartridges being the ultimate that they ignored any other technology.

The same thing happened with the Micro Acoustic stereo cartridges in spite of the almost universal praise for them.

I really lucked out on getting my EPC 450C II several years ago. The guy who had the eBay auction didn't know what he had. I think he assumed it was just another ceramic cartridge like the Tetrads he had in the auction. 25 bucks for all of them for me.

Doug

You were very lucky indeed!
i find the SC cartridge to be impervious to static. They don't seems to be affected as much as magnetic ones.

 

[Wurly1]

Here is Klaus Hönemann's contact page. He was at one time selling them through his website. I can not be sure he still has any but if he does, he is very nice to deal with. My experience was exemplary. I know he was and possibly still is a member here but I can not find his member name.
quadraphonie.de webpage contact.

Please consider looking around the rest of his site, you will find pictures of quad gear and enthusiasts from Germany, much is uncommon to rare, a word I really don't use often.

Thank you for the link

 

[Circular Vibes]

I think the Taya table is an upgrade from the original. It is possibly a CEC clone. It looks good in the cabinet and if you use the original turntable base and build a box for the receiver it will also look good. 8 ohm speakers makes your choices very easy for todays market.

 

[MidiMagic]

A few notes:

Speaker impedance has not been nearly the problem with solid state amplifiers as it was with tubes. Since the output of a tube was high impedance, a matching transformer had to be used to drive a low-impedance speaker, so they had taps on the transformer for 4, 8, and 16 ohm speakers.

Solid state amps are much more forgiving. Follow the instructions. The two main caveats are not to short the amp output or leave it unloaded.

Another possibility is to buy a 120V to 240V transformer or run a 240V outlet for your component. If you have a 3-wire service, 240 volts are available in your breaker box.

I used to have a Seeburg jukebox quad decoder. It was a derivitive of the Dynaquad system.

 

[Wurly1]

A few notes:

Speaker impedance has not been nearly the problem with solid state amplifiers as it was with tubes. Since the output of a tube was high impedance, a matching transformer had to be used to drive a low-impedance speaker, so they had taps on the transformer for 4, 8, and 16 ohm speakers.

Solid state amps are much more forgiving. Follow the instructions. The two main caveats are not to short the amp output or leave it unloaded.

Another possibility is to buy a 120V to 240V transformer or run a 240V outlet for your component. If you have a 3-wire service, 240 volts are available in your breaker box.

I used to have a Seeburg jukebox quad decoder. It was a derivitive of the Dynaquad system.

Yes you are right about tube amp which sometimes used some exotic impedance speakers sometimes impossible to find nowadays.
In the case of the SS1100-D, the outputs are AN272 (5 watts RMS) integrated circuits with a push-pull output configuration and two power supply (+13v and -13v). The outputs are direct capacitor-less and there is a speaker switch on the front panel to disconnect them.
With this configuration, there is no problems using it without speakers for a while, A precaution would be to plug some earphones to provide some load to the amp or keep the volume control at zero.

I currently use a 120v to 240v transformer but it's too bulky for permanent use.
It's a big and heavy 1500 watt unit. 26 x 24 x 17 cm or 10-1/4 x 9.5 x 6-3/4 inches while the SS1100D system only need 53 watts.
I also tried smaller travel-type transformer but they tend to overheat so i consider them to be unsafe.

So now i'm looking for a transformer with the following specifications:
primary: 120V
sec 1: 22.2v min 500 mA (all preamp, tuner and CD-4 decoder)
sec 2: 20v center tap (2 x 10v) min 2A (power output)
sec 3: 12v center tap (2 x 6v) min 500ma (lights)

All lights can be replaced by low power LEDs and therefore sec 3 is not mandatory.

I might also consider using 2 transformers providing their combined size is not too big for the available space.

 

[Doug G.]

Actually, tube amps will be more forgiving of an overload for a while, sometimes quite a while. A solid state amp will be damaged in short order with a substantial overload, putting two 4 ohm speakers in parallel, for example. Some solid state amps are designed to handle that but those are pretty rare. Almost all solid state amplifiers do not want to see less than 4 ohms impedance across the output transistors and that actually stresses the output devices in spite of what the manufacturer says.

Also, a solid state amplifier doesn't care if there is a load or not. If there is nothing connected across the outputs, there is no current flow and no heat.

 

[Doug G.]

Wurly, have you seen the Simran units which are step-up, step-down? They are about 5" X 4" X 3". They come with different wattage ratings. I bought one that's 200 watts max to run some British model train power packs and it works fine.

Of course, those power packs don't draw anywhere near 200 watts but it doesn't even get warm with those.

Doug