Audionics Space & Image Composer / Tate Audio

[Steve Kennedy]

Hi Steve,

Fascinating article so far, great to see all this in depth detailed info straight from the source.

I have always understood that Dolby Labs™ originally used QS as the basis for Dolby Stereo™, (which no doubt accounts for the film soundtrack of Tommy sounding like the tape machine was out of phase when listened to un-decoded in stereo).

Therefore if Dolby™ became a Licensee and swapped over to using Tate Chips in their Professional Cinema Products (remember little or no domestic Dolby™ Product, apart from Dolby 'B'™ NR of course, was around in those days.)

Does this mean the Dolby Surround™ encoding was changed to SQ? (which I think I remember reading something about on the Dolby™ Website) or are the Tate Chips capable of decoding other matrix's as well as SQ?

And thereafter as DPLII™ was (if I am correct say) developed by Jim Fosgate for Dolby™ Labs to Decode Dolby Surround™ Encoded material, does it not follow that when reproducing 'Matrix Quad' Material with DPLII then it would be SQ NOT QS that is correctly decoded as which seems to be the common opinion on this board.

Short of asking Ray Dolby(™?) himself, you sound like the guy to sort out this confusion once & for all. OR is my 'Logic' just a load of 'Reverse Polish'?

Also you mentioned that Tate hand built Directional Decoders from discreet components. Where any cct's ever published of this or similar discreet enhanced decoding schemes? Would be great to build one as a bolt-on to a Sansui QRX, all we need is the Schematics!

John - Liverpool UK
[email protected]

First, the Tate Directional Enhancement System is not a decoding system, it is an Enhancement system that requires a matrix decoder for a front end. While it is theoretically possible (Dolby actually did it) to feed the DES a signal from a non-SQ matrix, Tate was an SQ licensee and optimized performance using SQ as the model.

Because the Tate chips themselves don't decode anything, they were applied to the Dolby system in such a way that they improved what they already had going. In other words, a flavor of QS was the basis for the original Dolby Surround and the Tate System was used to create a new system better than and compatible to the original Dolby Surround. How much QS survived the transition is anyone's guess. You would have to ask someone at Dolby!

A Tate system built from discrete components would be huge, expensive and impossible to keep tuned. This is why it was reduced to IC form. Martin Willcocks (the Engineer who designed the Tate DES) had a magazine article in the works that would have allowed you to buy a Tate chipset and with a small PC board, make a DES that you could plug into your existing matrix decoder (I think I still have a copy of the article and PC layout somewhere). However, when the chips came out of fab at National Semiconductor and it became apparent that they did not work correctly, the article was shelved.

Steve

 

[Steve Kennedy]

Not to feed anyone's paranoia here but is it likely that the existing Tate units have as of now drifted out of adjustment?

Is there a source for the alignment procedure?

Also, I read somewhere that there are line-level taps in the Tates. Is it true?

I suppose it is possible to get some drift, but since the internal controls were painted to prevent movement and the major circuitry is on the Tate chip substrates it should be fairly stable. I have never seen one drift out of alignment myself. It is more likely that some of capacitors in the unit may become leaky and effect performance that way. The factory alignment should NEVER be messed with unless an LM1492 or RA402 Tate detector chip is replaced. Re-alignment won't compensate for other problems!

I don't remember that the alignment procedure was ever distributed but it was internally documented. I don't happen to have a copy (which is wierd because I was the one who designed the alignment procedure and did most of the Composer alignments myself).

There are 4 pots... 3 control voltage balance pots and a bias pot. The way we aligned them was:

1. By using an SQ Test Tone encoding circuit (our own design) we would feed the SQ signal pairs (CF/CB, RF/LF & RB/LB) individually and measure the resulting control voltages coming out of the detector chip (National LM1492N or Exar RA402). The balance pots were adjusted so that each pair put out the same control voltage when their signal was detected.

2. The Bias control was tweaked by ear while playing a small selection of SQ and Stereo material that was known to have certain qualities we could optimize for in the final audio presentation. This matched the output of our balanced interface circuit to the Tate VCA (Voltage Controlled Amplifiers) chips (National LM1494N or Exar RA404). The final test was ALWAYS by ear for the best compromise between cancellation and smoothness & accuracy of decoding.

3. Sometimes, a small tweak of a balance pot was necessary to get things sounding their best, but we always set the 3 balance pots my the numbers to get in the ballpark first. The chipsets were remarkably consistent which allowed us to develop a workable consistent alignment procedure.

Line Level taps? I'm not sure what you mean. The 4-channel output of an SQ matrix decoder is fed into the Tate detector and the VCA chips. The detector generates 6 control voltages based on the directional content of the input signals and these signals are "massaged", filtered and balanced by our our interface circuit which feeds the "corrected" control voltages to the VCA chips which in effect are turning the volume up and down on the 6 channels of control which are combined to become the 4 output channels you listen to.

Steve

 

[Steve Kennedy]

Jim Fosgate himself said that DPL-II will not properly decode SQ, it sums the back channels.

Steve,

do you have an opinion on which was better, the Tate 101a or the S&IC???

I have a LOT of Composer experience, but very little exposure to the Fosgate 101A. Fosgate did things a little differently than we did at Audionics as far as the alignment procedure. From the units I have had limited exposure to, it seems that the Fosgate units were initially optimized for maximum cancellation (their spec sheet quotes 35-50dB!). I doubt a Composer would be higher than 25-35dB after final alignment, nor need to be as this is already exceeding the standard phono cartridge L/R separation numbers.

While high separation makes an impressive demonstration of the system's capabilities, it can also create a "pinched" soundfield that is over-controlled. This can suppress delicate ambience effects while potentially generating audible control artifacts because of how "agressive" the DES is set-up. I only heard a few early units so it probably wouldn't be fair to assume that the majority of the units were that way. Jim Fosgate has a real good ear for these things so I have no doubt that the production units were optimized similarly to the Composer as time went on and experience was amassed.

Of course, in a high end system the Composer had a few advantages in the Axial Tilt compensator circuit, Class A 8-pole precision matrix decoder and 4-channel bypass input for external decoders or discrete sources. I always found the Solo Null mode and Spatial Display to be a great help for adjusting the input balance control (very important for maximum performance).

Steve

 

[Steve Kennedy]

I suppose it is possible to get some drift, but since the internal controls were painted to prevent movement and the major circuitry is on the Tate chip substrates it should be fairly stable. I have never seen one drift out of alignment myself. It is more likely that some of capacitors in the unit may become leaky and effect performance that way. The factory alignment should NEVER be messed with unless an LM1492 or RA402 Tate detector chip is replaced. Re-alignment won't compensate for other problems!

I don't remember that the alignment procedure was ever distributed but it was internally documented. I don't happen to have a copy (which is wierd because I was the one who designed the alignment procedure and did most of the Composer alignments myself).

There are 4 pots... 3 control voltage balance pots and a bias pot. The way we aligned them was:

1. By using an SQ Test Tone encoding circuit (our own design) we would feed the SQ signal pairs (CF/CB, RF/LF & RB/LB) individually and measure the resulting control voltages coming out of the detector chip (National LM1492N or Exar RA402). The balance pots were adjusted so that each pair put out the same control voltage when their signal was detected.

2. The Bias control was tweaked by ear while playing a small selection of SQ and Stereo material that was known to have certain qualities we could optimize for in the final audio presentation. This matched the output of our balanced interface circuit to the Tate VCA (Voltage Controlled Amplifiers) chips (National LM1494N or Exar RA404). The final test was ALWAYS by ear for the best compromise between cancellation and smoothness & accuracy of decoding.

3. Sometimes, a small tweak of a balance pot was necessary to get things sounding their best, but we always set the 3 balance pots my the numbers to get in the ballpark first. The chipsets were remarkably consistent which allowed us to develop a workable consistent alignment procedure.

Line Level taps? I'm not sure what you mean. The 4-channel output of an SQ matrix decoder is fed into the Tate detector and the VCA chips. The detector generates 6 control voltages based on the directional content of the input signals and these signals are "massaged", filtered and balanced by our our interface circuit which feeds the "corrected" control voltages to the VCA chips which in effect are turning the volume up and down on the 6 channels of control which are combined to become the 4 output channels you listen to.

Steve

Ooops... there's that aging mind betraying me again. The ACTUAL Tate Chip part numbers are:

Tate Detector
National Semiconductor = LM1852N
Exar Integrated Systems = RA402

Tate VCA
National Semiconductor = LM1853N x 2
Exar Integrated Systems = RA404 x2

BTW... the Space & Image Composer web site is up and initially operating at:

www.spaceandimagecomposer.com

Steve

 

[Malcolm2010]

Steve,
From what you have described, the simple replacement of all ageing electrolytic capacitors should not require a re alignment. I have been holding off doing this just in case it caused problems with setup. Am I right in assuming this?

Cheers

Malcolm

Happy S&IC owner

 

[john e. bogus]

Steve-

Great to see your site up and running....I'd been waiting with baited breath for the detailed technical info and schematics....THANKS!! As you're probably aware of, the demand for these units (S&IC, Tate) is incredible, and finding one used at a reasonable price is impossible these days. Doubtless there are plenty of people like myself who are technically knowledgeable and aren't afraid of a soldering iron, but simply aren't willing to pay through the nose for a 20+ year old piece of gear that will come due for recapping at any time. In light of this situation, as well as the fact that the schematics have been "released", is there any possible way to find a schematic of the chips' inner workings, or of the original discrete component prototype? You mention that the circuit is "huge", and that thermal stability is hard to acheive....but these wouldn't be concerns for those of us who would actually take the time and trouble to build something like this from scratch. What about synthing stereo into 5.1 instead of 4 channels? Apparently some of the Audionics products had this feature.....did any of them perform as well as the Tate did for synthesizing surround? If so, which are the "good ones"? Perhaps one of those units could still be had at a reasonable price for those willing to accept not having the SQ decoding ability...... The Martin Willcocks article sounds interesting, but puts us back to the problem of finding out what circuitry is actually inside the IC's. Perhaps a group effort could be made to pool resources to have the IC's reproduced? Doubtless the production of IC's is a much more competitive field and is cheaper than it was 25-30 years ago.....if every person who was willing to spend over a grand on a Tate would put that dough towards a communal effort to repro the chips, not only would existing owners be assured of having replacement parts available, but then EVERYBODY would be able to have this kind of performance available at a reasonable cost......

Yours Truly,
john e. bogus

 

[deepsky4565]

I have found the Fosgate Audionics Models 3, 3A, 4 and 5 to be at least as good as the Tate 101A for synthesizing surround from stereo, with less pumping. Plus you can have a center or sub channel, too. For me it blows away everything else, including VarioMatrix, and DPLII. Cheap on ebay compared to Tates. I send practically everything stereo through my 3A, I love it!

I do not know the internal circuitry of these units, but if there is a seperate DES section, it would seem to me that we could hack in a SQ or even QS matrix. Steve, do you know anything about this? Thanks for your cool site, it is a great resource.

 

[proufo]

Line Level taps? I'm not sure what you mean. The 4-channel output of an SQ matrix decoder is fed into the Tate detector and the VCA chips. The detector generates 6 control voltages based on the directional content of the input signals and these signals are "massaged", filtered and balanced by our our interface circuit which feeds the "corrected" control voltages to the VCA chips which in effect are turning the volume up and down on the 6 channels of control which are combined to become the 4 output channels you listen to.

Steve

Hello Steve and thanks for your reply.

I mean the four signals before the balance and volume circuitry, which are redundant with modern multichannel receivers and preamps that can take one or several mch input(s).

Best regards.

 

[proufo]

Steve-

Great to see your site up and running....I'd been waiting with baited breath for the detailed technical info and schematics....THANKS!!

Hello again.

What the URL for Steve's site?

Also, is it possible that existing chips for currrent technologies such as DPLII could be grouped in a custom configuration to produce an SQ/Tate workalike?

 

[Cai Campbell]

I have found the Fosgate Audionics Models 3, 3A, 4 and 5 to be at least as good as the Tate 101A for synthesizing surround from stereo, with less pumping. Plus you can have a center or sub channel, too. For me it blows away everything else, including VarioMatrix, and DPLII. Cheap on ebay compared to Tates. I send practically everything stereo through my 3A, I love it!

I'm afraid I don't agree. I've used the Fosgate Model 3A and 4 along with the Tate II 101A and QSD-1. What constitutes "pumping" and to what degree is very subjective. All of these units "pump" to some degree, but in different ways and depending on the material being played. It is very hard to describe the differences, but with enough listening you can hear the shortcomings of any of the units. The bottom line is that none of them are perfect, but you have to listen to each and determine which you, as an idividual, prefer. There is no "right" answer. It is a matter of personal preference. With that said, I personally prefer both the Tate II 101A and QSD-1 over the Fosgate Model 3A and 4 by a wide margin.

However, the Fosgate Model 3A and 4 can usually be picked up very, very cheaply. For the price, they are certainly worth checking out. I certainly wouldn't recommend to someone that they are sufficient replacements for a Tate or QSD-1, because they aren't. They are different animals altogether. Better animals? I don't think so, but that is an individual determination.

 

[Steve Kennedy]

Steve,
From what you have described, the simple replacement of all ageing electrolytic capacitors should not require a re alignment. I have been holding off doing this just in case it caused problems with setup. Am I right in assuming this?

Cheers

Malcolm

Happy S&IC owner

The only capacitors that might affect the alignment would be film capacitors in the SQ Matrix (the yellow ones at the input side) or in the filters used around the Tate chips' DC control lines (the large Green .33uF caps... not all were Green, though).

Changing the electrolytic capacitors used for DC filtering, display driver or those used for audio coupling should only make things better by making the unit resemble more closely the condition it was in when it was originally aligned at the factory!

This was why I mentioned that your first inclination shouldn't be to try to re-align a Composer because it isn't sounding as good as it used to. There is probably a developing problem (like a dried up or leaky cap or cold solder joint or oxidation in an IC socket) responsible for the decline in performance and fixing the real problem should bring the performance back. If you try to "lean" things to make it work better by mis-adjusting things you won't have as easy a time at getting back to where you want to be once you are forced to fix the original problem (which presumably would get worse).

Steve

 

[Steve Kennedy]

Hello Steve and thanks for your reply.

I mean the four signals before the balance and volume circuitry, which are redundant with modern multichannel receivers and preamps that can take one or several mch input(s).

Best regards.

If you go to my site (here's the link again for the person who didn't spot it elsewhere):

www.spaceandimagecomposer.com

and download the SAIC Tate DES schematic you will notice several important points having to do with your question... not only do the 4 audio outputs leave the Tate VCA chips but all of the balance and output level controls also connect to the chips.

What this implies (and I will confirm it right now so there is no misunderstanding) is that the front panel controls are NOT adjusting audio signals! Since we are using Voltage Controlled Amplifiers we can control all the output audio signals by using the pots to change the DC voltages used to control the audio signals inside the Tate VCA chips.

This allows us to add the remote control of all these pots but without having to worry about shielded cable, hum, RF interference or cable length! All these controls lines are DC controlled. If you didn't want these controls, you could simply replace them them on the schematic with voltage dividers that would set your balance and line level output to minimize noise.

Also, if you count the pin numbers on the Tate VCA chips (18-pin package) you will notice that there are NOT any unused pins which might indicate an unused line output capability.

Steve

 

[Steve Kennedy]

Steve-

Great to see your site up and running....I'd been waiting with baited breath for the detailed technical info and schematics....THANKS!! As you're probably aware of, the demand for these units (S&IC, Tate) is incredible, and finding one used at a reasonable price is impossible these days. Doubtless there are plenty of people like myself who are technically knowledgeable and aren't afraid of a soldering iron, but simply aren't willing to pay through the nose for a 20+ year old piece of gear that will come due for recapping at any time. In light of this situation, as well as the fact that the schematics have been "released", is there any possible way to find a schematic of the chips' inner workings, or of the original discrete component prototype? You mention that the circuit is "huge", and that thermal stability is hard to achieves....but these wouldn't be concerns for those of us who would actually take the time and trouble to build something like this from scratch. What about synthing stereo into 5.1 instead of 4 channels? Apparently some of the Audionics products had this feature.....did any of them perform as well as the Tate did for synthesizing surround? If so, which are the "good ones"? Perhaps one of those units could still be had at a reasonable price for those willing to accept not having the SQ decoding ability...... The Martin Willcocks article sounds interesting, but puts us back to the problem of finding out what circuitry is actually inside the IC's. Perhaps a group effort could be made to pool resources to have the IC's reproduced? Doubtless the production of IC's is a much more competitive field and is cheaper than it was 25-30 years ago.....if every person who was willing to spend over a grand on a Tate would put that dough towards a communal effort to repro the chips, not only would existing owners be assured of having replacement parts available, but then EVERYBODY would be able to have this kind of performance available at a reasonable cost......

Yours Truly,
john e. bogus

Unfortunately, you are up against a variety of hurdles. First, the discrete-component version of the Tate schematics used to fab the chips has only ever been seen by Martin Willcocks (the designer), the other people at Tate Audio (Wesley Ruggles, Jr.), the I.C. fab guys at National Semiconductor (or Exar) and the lawyers involved in the patent process. You can find the first page of the original Tate patent (Patent #3,944,735 dated March 16, 1976) in the Composer Misc Documents PDF on my web site. This information found in the patent is probably as close as any of us would come to seeing the discrete schematic (unless Martin Willcocks himself still has a copy and would like to share it).

Secondly, it is still expensive to tool up a facility to make a run of chips. It isn't about buying them one or two at a time, you either front the tens or hundreds of thousands of dollars to pay for the tooling and a run of tens of thousands of chips are "free", or you pre-order an even bigger quantity and pay as much as necessary per chip so the manufacturer can recoup his costs and make a profit. We aren't talking about digital programmable logic arrays here (off the shelf), this is 100% analog custom fabrication which can get very spendy.

The only method I can think of to make things less expensively would be to model the system in a DSP chip, but this would be a big programming job for a specialist.

Only Fosgate-Audionics continued to manufacture surround decoders in quantity after Audionics went out of business in the mid-eighties and it must be these surround decoders you are thinking about. I myself have a Fosgate-Audionics DSM-3610 (Digital Space Matrix) post-Tate unit of Jim Fosgate design (Bob Popham worked on these too) that actually creates a 7.1 output from stereo input sources. If you are a "quadophile", listen to a lot of classical SQ and are really picky you may not like like this unit. However, it DOES do a credible job with stereo and movie sources and it isn't all that bad in the smoothness and pumping department.

While it wouldn't be bad for rock music and action films, it doesn't have the same ambient quality that the Tate decoders exhibit in my opinion. It all depends on what you need or expect. I could certainly live with the unit for many types of program material but only because I can separate my "serious" listening from "recreational" listening that might include light conversation, beer and pizza while the system plays in the near background.

Fosgate went on to make better units, but the Digital Space Matrix boxes still blow away the pre-Tate SQ decoders for stereo and movie soundtrack enhancement. They just aren't optimized for SQ or quad sources so positional accuracy and ambience quality suffers. These units also have a lot of "bells and whistles" so system connectivity, remote control and display indicators probably take a front seat over audio integrity.

Steve

 

[john e. bogus]

Steve-

Perhaps Martin Willcocks could be convinced to share the discrete schematic of the IC's? You imply a that a good bit of secrecy was involved at one time..... Yes, I'm well aware of the production cost of IC's.....considering that people are willingly spending over a grand on used equipment that contains these chips, it would only take 100 of them (or, say, 500 people to ante up $20 each) to come up with the cost of a production run.....Exar probably still has at least the original specs for the chips, assuming that there's no legal issues involved, they would probably quote a price for a run of repro IC's to anyone who inquired seriously..... The DSM you mention sounds interesting....were they produced in quantities enough to still be readily available? You say Fosgate went on to make better units.....do you mean better for synthesizing surround? If so, what else is worth looking for?

Yours Truly,
john e. bogus

 

[proufo]

What this implies (and I will confirm it right now so there is no misunderstanding) is that the front panel controls are NOT adjusting audio signals! Since we are using Voltage Controlled Amplifiers we can control all the output audio signals by using the pots to change the DC voltages used to control the audio signals inside the Tate VCA chips.

This allows us to add the remote control of all these pots but without having to worry about shielded cable, hum, RF interference or cable length! All these controls lines are DC controlled. If you didn't want these controls, you could simply replace them them on the schematic with voltage dividers that would set your balance and line level output to minimize noise.

I'd guess this is very unusual even today. Do the remote-controlled Marantz Quad receivers have a similar scheme?

Thanks Steve.

 

[The Quadfather]

Actually the use of VCA's is quite common today. It wasn't back then. Any time you are using a volume control that operates by pushing a button instead of turning a knob, you are dealing with voltage controlled amplifiers. it is uncommon to see them linked to traditional pots like they are in the Composer.

The Quadfather

I'd guess this is very unusual even today. Do the remote-controlled Marantz Quad receivers have a similar scheme?

Thanks Steve.

 

[The Quadfather]

I'm very curious. If it is so expensive to make ICs from scratch, then why was it economically feasible to do it in 1979? Did Audionics lose big money on the Composer? A good project would be to track down all of those Dolby Decoders that were used for theaters and that employed chips purchased from Audionics. They would provide a stock of parts so that ailing Space and Image Composers could be repaired. Is there a chance that Dolby didn't use them all? I guess I would need to contact Dolby on this issue.

The Quadfather

 

[Steve Kennedy]

I'm very curious. If it is so expensive to make ICs from scratch, then why was it economically feasible to do it in 1979? Did Audionics lose big money on the Composer? A good project would be to track down all of those Dolby Decoders that were used for theaters and that employed chips purchased from Audionics. They would provide a stock of parts so that ailing Space and Image Composers could be repaired. Is there a chance that Dolby didn't use them all? I guess I would need to contact Dolby on this issue.

The Quadfather

This message is long because I am trying to cover ground on multiple inquiries in this thread all in one reply.

The people at Tate Audio had this vision that the National Semiconductor chips were going to work correctly. I think National Semiconductor had an exclusive on the chips and bought into the whole thing like a "partner" because they believed that these chips could be the next "Dolby Noise Reduction" type chip that everyone would be using. I think it was National's early participation that made the Tate chip fabrication economically feasible on the first go-around.

If the chips had worked properly from the start, the first generation of "simple" Tate decoders would have been available in short order for $150-$300, not the much more expensive units from Audionics and Fosgate. There is a document on my web site which quotes this price (the first people who left deposits on the Composer in 1976 got theirs for the promised $300 or at whatever level they bought in at!). There would have been near zero development time because Tate (who would have still had Martin Willcocks going full-bore on the project) would have been able to provide all the development materials, schematics and proto boards to get all interested parties started up quickly. Since this never happened, Tate didn't stand to make any money off this system because it couldn't convince the large manufacturers to get behind a flawed chipset.

As it was, I believe Martin Willcocks left Tate shortly after the chips were confirmed to be non-working. Tate had invested everything it had to get to this point and I don't think Martin could see any continuing income under the circumstances. National had already invested heavily in getting the project to the point it was at and denied it had made any mistakes. I am sure this was partially due to the fact that their engineers really didn't know what the chips were SUPPOSED to sound like and hadn't developed any definitive tests to prove proper operation one way or another.

The technical "pissing match" between Tate and National eventually turned into a full-blown lawsuit. Audionics got involved because we were the first ones to show an interest in the system (even after the chips were found to be less than working) and had some available expertise as we had been working on our own Shadow Vector SQ decoding system. That's where my association with the Tate System started, when we took on the job of trying to find a way to make the chip set functional despite the fabrication problems. This marked the beginning of 3 grueling years of development on a daily basis until all the involved parties were happy enough with the outcome to sign-off and go for it.

Tate and Audionics certainly didn't make any profit on the project. Every one of those Composers was subsidized heavily by all the parties involved and it was a real effort to get some of these things out in the world so that all the development work wasn't in vain. If we couldn't recoup the losses at least we could advance the art in some way, and get one for ourselves (we were all "believers" and loved the unit long before it hit the streets). As Charlie Wood once remarked... "At least I got my Composer and a spare set of chips out of it"!

National had made a lot of the investment themselves in order to make the big bucks on the back end, but they lost out as much as anyone else when the original chips didn't work. I am not sure why they pulled out... were they cutting their losses or was Tate threatening to get ugly with a lawsuit early on because they had no funding to continue the development?

In any case, I believe it was the National underwriting in addition to the Tate Audio investment that made the chips possible in 1979. You remove all of that and try to fund it yourself, you are looking at big bucks!

As far as Exar still having the fab materials, well there is a few problems with that idea. Exar could only legally make the Tate chips and sell them to Tate Audio, who in turn sold them to the manufacturers. This was how Tate guaranteed they got their cut and they could control not only the price but the distribution. Exar probably couldn't make any without Tate's say-so and Tate hasn't existed in quite some time. Exar isn't the owner of the design just a contract fabrication house in this case.

I wouldn't be surprised if either Exar returned the fab materials to Tate when the end came OR if Tate had offered to sell the whole thing to Dolby for a large sum of money that Dolby wasn't willing to pay! Add to this the fact that Exar's current product line-up is almost entirely in the high-speed data communications area or Video Processing. The Tate chip set is probably a bit out of their current capabilities for easy tooling changes.

I am sure Dolby protected its' interests by stocking extra supplies of the Tate chips to keep things covered until they could design a replacement that didn't need them. Do they still exist? Are there spares still in stock? My guess would be that most of that stuff is long gone, thrown out and written off. It is too expensive to keep old stuff in stock forever when you have to pay taxes on it every year! I am reasonably sure nobody thought to take them all home and put them in a box in case they were worth something 20 years down the road!

...but you don't know for sure unless you ask and stranger things have happened! You would just have to find someone at Dolby was was there 20 years ago. That might be tougher than finding a Tate chip set!

Steve

 

[deepsky4565]

Cai,

when did you use a FA 3A? When you say you prefer the Tate to the later Fosgate units have you really compared them head to head? I have for hours, and I stand by my opinion backed up with lots of listening time head to head, and the later Fosgate units are superior, no question. I have both units still in my system, yet, the Tate, while it is impressive, doesn't do anything better than my 3A except SQ sources in SQ mode. I have talked to Bob Popham at length about these units, and the Rock mode in the FA units are the same matrix as the stereo to surround mode of the Tate, and in detailed listening, I agree. I auditioned a Model 4 with you, and we both heard artifacts with it. It was one of the poorer performing units I've had, and ended up giving it away to someone for a different purpose. If you are basing your opinion on that one unit, I'd have to say you should check out a good one. When we did that we were comparing it to a QSD-1, not a Tate, so it is difficult to compare it to the Tate. I also recall much listening done during that session was material you already decided the QSD-1 wasn't very impressive with. I'm glad we all have different opinions, but I can't just let my opinion be trashed when I was there!!! I have used several different QS synthesizers, including a restored QSD-2, and heard Cai's QSD-1. They are great, but for me don't hold a candle to my 3A for synthesizing surround. The primary difference is the QS matrix places center mixed sources full center, that means equal volume from all four channels. The Fosgate matrix places center sources front center. This is one of the major reasons I prefer the Fosgate, I like vocals front center. To me this increases the sense of directionality and discreteness. I am not knocking any one elses opinions, but can't let this pass by without comment. Cai, if you have a 3A, let me know, but as far as I know your experience with them is limited to one poor unit for a short time, not against the Tate. If you have one since that time, it could be a poor performer too, just as the Tates differ unit to unit. If your wondering about my Tate, Bob Popham went through it and affirms it is a "good" one.

 

[The Quadfather]

I can't speak for Cai, but one time I loaned Tab a copy of Billy Joel "Turnstiles", to process for DTS. My copy was surprisingly flawless, considering that it had gotten lots of play. Tab processed the unit through a Fosgate 101A. When I listened to the DTS version, I noticed speaker switching artifacts that I hadn't noticed when the "master" was played through my own Composer. It seems like Cai was involved with that project somehow, but I can't remember how. I realize it was a limited test, but that's what I got from it. I like the Composer better.

The Quadfather

Cai,

when did you use a FA 3A? When you say you prefer the Tate to the later Fosgate units have you really compared them head to head? I have for hours, and I stand by my opinion backed up with lots of listening time head to head, and the later Fosgate units are superior, no question. I have both units still in my system, yet, the Tate, while it is impressive, doesn't do anything better than my 3A except SQ sources in SQ mode. I have talked to Bob Popham at length about these units, and the Rock mode in the FA units are the same matrix as the stereo to surround mode of the Tate, and in detailed listening, I agree. I auditioned a Model 4 with you, and we both heard artifacts with it. It was one of the poorer performing units I've had, and ended up giving it away to someone for a different purpose. If you are basing your opinion on that one unit, I'd have to say you should check out a good one. When we did that we were comparing it to a QSD-1, not a Tate, so it is difficult to compare it to the Tate. I also recall much listening done during that session was material you already decided the QSD-1 wasn't very impressive with. I'm glad we all have different opinions, but I can't just let my opinion be trashed when I was there!!! I have used several different QS synthesizers, including a restored QSD-2, and heard Cai's QSD-1. They are great, but for me don't hold a candle to my 3A for synthesizing surround. The primary difference is the QS matrix places center mixed sources full center, that means equal volume from all four channels. The Fosgate matrix places center sources front center. This is one of the major reasons I prefer the Fosgate, I like vocals front center. To me this increases the sense of directionality and discreteness. I am not knocking any one elses opinions, but can't let this pass by without comment. Cai, if you have a 3A, let me know, but as far as I know your experience with them is limited to one poor unit for a short time, not against the Tate. If you have one since that time, it could be a poor performer too, just as the Tates differ unit to unit. If your wondering about my Tate, Bob Popham went through it and affirms it is a "good" one.