The Bell SQ Quadmatrix decoder addon - anyone got some info?

[wizard]

The old Bell Radio and Television corp did an add on SQ decoder.
What year was it released?
It has logic enhancement one assumes not full logic?
It had power amps for the rear - modest 15 watts per channel?
Just wondering as there is very little info on it anywhere.

SQ decoding came from very basic (nothing) to the full blown fostgate tate along with sonys SQ 2020 toward the top end of logic decoding.
Fostgate had something to do with the SQ era and when it died Mr Dolby purchased the patents for 250K and created dolby prologic etc. when DTS brought out neo 6 , Mr Dolby went back to Mr Fostgate to create Dolby prologic II.
Quadraphonic never died it just got taken over and redeveloped.
The ultimate Sansui QX-9000? at the end of the era did the full monty very well I am led to believe having all systems SQ, QS and CD-4 done to the highest quality.

Not talking about QS or CD4 just wondering about more info on the local Bell SQ Quadmatrix decoder and what generation of CBS logic it used?

Cheers for looking more thanks if you Know some info.
Regards
Bill

[Michael Wong]

Did those early systems use logic steering ?

:eek:

I imagine they would be quite rudimentary compared to today's systems, with noise and pumping effects as the content moved from channel to channel.

[wizard]

Hi Michael,

I cannot answer that question. at the end of the era 1976 ish the Fosgate Tate was the system (30db plus separation all channels), that had it been released at the start, SQ would have won and continued, it had maximum separation all channels and on all diagonals - when you realise he invented Prologic II - yup makes sense Mr Fosgate did well.

The late 1976 decoders all had full logic steering which produced no pumping - was fast and reliable.
In March 1974 CBS released a variable Blend SQ circuit board that had a full-logic decoder using Motorla integrated Circuits which manufacturers could licence and use.
If the Bell came out around this time it is possible it contained this circuit board as the Bell states a variable blend.
The CBS circuit could be used in 4 ways, Basic Matrix L1, L2, L3 (L being Logic mode) The L3 mode had a approximate relative cost of $USD14 but only gave infinity across the front 20db front to back and diagonals but only 15db across the back channels.

Just wondering still about the Bell though.

SQ thru home theatre amp is great using prologic II but some directionality is not quite what it was intended - so I am led to believe.

[Michael Wong]

Was the CBS circuit licensed from Peter Scheiber ?

Back in 1970 he created an SQ codec using gain-riding where predominant channels had their level increased, while lesser channels had their gain reduced. This was licensed to Sony and CBS.

His later (1979-ish) 360º Decoder used a combination of gain riding and selective crosstalk cancellation across six axes, instead of the more common four.

Hard to believe those early full logic decoders were artifact-free.
I remember the early Pro-Logic decoders from Shure and Lexicon and they were pretty awful sounding. It was Fosgate (again) to the rescue with his 70mm mode (faster logic, full bandwidth rear channels) to make surround sound listenable.

Wasn't Bell tied up with Pye (who used the Sansui SQ Matrix) ?

[wizard]

Can't answer that one Michael about Mr Scheiber, certainly Fostgate did his own thing latter with the Fostgate Tate.
Bell at one time had a factory in Dominion Road In Auckland, I thought Pye ended up at Waihi on the Coast making TV's, I would have considered them rivals?

PYE and QS now there is a thought. What PYE models contained the Sansui decoder?

[moby]

Bell at one time had a factory in Dominion Road In Auckland, I thought Pye ended up at Waihi on the Coast making TV's, I would have considered them rivals?

PYE and QS now there is a thought. What PYE models contained the Sansui decoder?

I worked in the design dept in that Dom rd factory (now Geoffs Emporium) at the time that SQ decoder was brought to market. It was a full logic system lifted straight off the Motorola MC1312/1314/1315 chipset data sheet (datasheetarchives still has the info on these dinosaurs). I cannot recall ever having seen a PYE version.
M

[Colin^]

I used to use a Bell SQ Decoder/amp in the mid 70's. I bought it new in 1975 or 76 at a trade fair in Napier when it was introduced and had my Sansui au 101 intergrated modified to a pre/power amp.


I think it was about 20 watts per channel the SQ decoder amp.

[wizard]

Cheers Guys for that info. I would consider one at the right price now.

[wizard]

Well bought one. Call me a fool just like to see how well it does on the SQ vinyl I have.

[wizard]

Is there any literature still in existence?

[wizard]

Picking up a Magestic model also. Weren't Bell Magestic one? Was one an up market one of the other? or both the same in reality. Figure if the first re configuration fails, at least I will have parts from the second to repair my folly. Call me mad. Now have parts for speaker protection, new power supplies and a I hope a better 50 watt amp section and toroidal transformer on the way. Xmas DIY.

[moby]

Bell and Majestic all came out of the same factory.

[wizard]

Cheers Moby.
Well then two of the sameous so to speak. Different clothing same internals.