(1974-12) SQ Stereo Enhancement [CBS Labs]

QuadraphonicQuad

Help Support QuadraphonicQuad:

J. PUPSTER

💿🐕 Senior Disc Chaser 🎸
QQ Supporter
Joined
May 30, 2017
Messages
11,312
Location
CALIFORNIA (CENTRAL)
Make sure your location settings are set Worldwide on the left side in eBay;
Chips, don't forget the sodas!

chips.JPG
 

par4ken

2K Club - QQ Super Nova
QQ Supporter
Joined
May 28, 2011
Messages
2,575
Location
NW Ontario
Nope - highly likely! All you need is a pile of random chips and a printer. It is a massive industry.
Very highly unlikely, check the sellers feedback! While it would be easy to pass off something like 741 op amps as something much higher grade, (as most people would not be able to check). You can't fake these chips, fakes would just not work!

Paypal and eBay would be on your side as well! Buy with confidence!
 

par4ken

2K Club - QQ Super Nova
QQ Supporter
Joined
May 28, 2011
Messages
2,575
Location
NW Ontario
When I purchase some I'll let you know if they work or not. I have the Heathkit decoder I'm experimenting with. I have a few good MC1312P chips and MC1314P as spares but I blew all my MC1315P's years ago while farting around with it (one like it, my original board). So I need some more MC1315P's. The chips currently on the board are all good.

Incidentally I also have some MC1313P's the 12Volt version of the MC1312P.
 
Last edited:

par4ken

2K Club - QQ Super Nova
QQ Supporter
Joined
May 28, 2011
Messages
2,575
Location
NW Ontario
Most of the listings shown do have the date code, I don't know what that CPDD number is supposed to be. But once again you are fully protected when purchasing through eBay. Also it's not a lot of money to begin with! I would think it best to avoid those with the weird number where the date code is supposed to be.
 

Soundfield

1K Club - QQ Shooting Star
Joined
Dec 29, 2011
Messages
1,776
Location
Essex, UK
Also it's not a lot of money to begin with!
Frankly it's that which also fuels my suspicions. For years these chips were almost unobtainable and when they did show up they were pricey. But all of a sudden, decades after they ceased production, they have all magically appeared again in China and for next to nothing.
 

kfbkfb

1K Club - QQ Shooting Star
QQ Supporter
Since 2002/2003
Joined
Feb 20, 2003
Messages
1,486
Location
Midwest USA
Since this is an arbitrary surround sound creation method, does it matter that much if the circuits produce ~60 degree or ~120 degree phase shifts instead of 90 degrees (or multiples thereof)?

Is it worth the trouble to get actual SQ ICs - some regular opamps and some (simple) phase shift circuits should be able to emulate the SQ stereo enhancement preprocessor well enough.


Kirk Bayne
 

par4ken

2K Club - QQ Super Nova
QQ Supporter
Joined
May 28, 2011
Messages
2,575
Location
NW Ontario
Frankly it's that which also fuels my suspicions. For years these chips were almost unobtainable and when they did show up they were pricey. But all of a sudden, decades after they ceased production, they have all magically appeared again in China and for next to nothing.
Yes but there could've been stocks of parts in the orient as that's where most of the equipment was manufactured. As for price, if there is a stock pile that no one needs nor wants the price of the parts will reflect that! I used to purchase from domestic distributers that would've got parts directly from Motorola, so as soon as they were no longer manufactured there was no more supply.
 
Last edited:

par4ken

2K Club - QQ Super Nova
QQ Supporter
Joined
May 28, 2011
Messages
2,575
Location
NW Ontario
Since this is an arbitrary surround sound creation method, does it matter that much if the circuits produce ~60 degree or ~120 degree phase shifts instead of 90 degrees (or multiples thereof)?

Is it worth the trouble to get actual SQ ICs - some regular opamps and some (simple) phase shift circuits should be able to emulate the SQ stereo enhancement preprocessor well enough.


Kirk Bayne
Yes for the decoder/encoder I would suggest using the Fosgate circuit. It's six pole and all the parts are readily available, but I would recommend using a better op amp than the TL084. On the other hand the MC1312P and the after market ECG/NTE type replacements are also readily available.

The enhancement circuit should produce 90° phase shifts as that's what you need to simulate SQ encoding.
 
Top