I am totally new here, but a Jim Fosgate fan

[vinylguy4]

FWIW, I actually sent these to Robert Popham some time back to see if they were legit. He told me they were not correct and doubted the authenticity for a couple of reasons. But who knows, he might have been sly about the issue.....

The signature matches what JF signed on a note he sent me years ago.

 

[barfle]

There will be a boatload of Foz circuit diagrams, layouts and possibly notebooks in my possession in about a month. Could be very useful? I hope.

I’ll be interested in whatever you end up with.

 

[par4ken]

FWIW, I actually sent these to Robert Popham some time back to see if they were legit. He told me they were not correct and doubted the authenticity for a couple of reasons. But who knows, he might have been sly about the issue.....

Odd, who would fake a Tate schematic? The basic audio circuitry is not rocket science. The magic is done with the DES chips helped along by the interface circuit. The interface (Q8) "Directional Control Circuit" is simply shown as a block, no details. I guess that Jim didn't want that secret let out!

I always wondered why he chose to use the TL084 op-amp when the lower noise TL074 was available for only pennies more. In any case better op-amps can be simply plugged into the sockets. The unit also uses the very common 4066 analog switch.

The only unobtainium parts are the DES chips. The Directional Control Circuit (Interface) would also be problematic should it ever fail, In addition to having no documentation I understand that portion of the board is encased in epoxy.

 

[par4ken]

If you look inside it is quite easy to distinguish version I from version II chipsets. The newer Exar chips were built in a 14 or 16-pin DIP package rather than the 18-pin DIP package of the Nationals, so they had to be mounted "hi-rise" style on an elevated adapter board that rose above all the surrounding components. The models with National chips had the detector chip mounted on the PC board itself (between two rows of large green poly capacitors) .

Steves statement tells how to identify a board that was designed for the National chips but had been retrofitted with an elevated adaptor board to convert it to the Exar (Tate II) chips. However not mentioned is that latter units (such as mine) had a redesigned board where the detector chip was also mounted directly to the board without requiring the adaptor.

Some fascinating tech history about Fosgate and the development of the Space & Image Composer from Steve Kennedy's experience :

https://www.quadraphonicquad.com/forums/threads/audionics-space-image-composer-tate-audio.2645/
And from even a bit earlier dealing with Fosgate Audionics and the Shadow Vector decoder from Lynn Olson starting at post #52:

https://www.quadraphonicquad.com/forums/threads/sq-shadow-vector-soundfield-mapping.25293/page-3

I would love to hear more from both Steve and Lynn!

 

[quadaholic]

There will be a boatload of Foz circuit diagrams, layouts and possibly notebooks in my possession in about a month. Could be very useful? I hope.

Mike, it's CP. Glad to see you've taken the plunge on QQ!

 

[Sonik Wiz]

Steves statement tells how to identify a board that was designed for the National chips but had been retrofitted with an elevated adaptor board to convert it to the Exar (Tate II) chips. However not mentioned is that latter units (such as mine) had a redesigned board where the detector chip was also mounted directly to the board without requiring the adaptor.

I would love to hear more from both Steve and Lynn!

For those interested here's some more info on Shadow Vector from Lyn Olson:

https://positive-feedback.com/audio-discourse/shadow-vector-emerges-from-the-shadows/
Some of this over laps his posts on QQ but there are some new points included. It's great that Lynn & Steve have made some good on line knowledge about their product designs. Too bad Jim Fosgate never did. Or maybe @MikeWiz knows some secret links???

 

[EASpeakeasy]

Thank you fellow members for all of this great information. I recently obtained what appears to be a prototype of the car audio Tate 201. It's a bit rough and will have to be dialed in. I'm hoping the chip sockets I see inside are for other uses and aren't missing but perhaps the schematics for the 101 will give me a clue. Naturally, I am grateful for any 201 documentation you find and I hope to chronicle the repair/research of this unit on this site.

 

[Sonik Wiz]

Thank you fellow members for all of this great information. I recently obtained what appears to be a prototype of the car audio Tate 201. It's a bit rough and will have to be dialed in. I'm hoping the chip sockets I see inside are for other uses and aren't missing but perhaps the schematics for the 101 will give me a clue. Naturally, I am grateful for any 201 documentation you find and I hope to chronicle the repair/research of this unit on this site.

 

[jaybird100]

View attachment 103956 I had his Gavotte II, which was similar to the 201, but RM based. The unit claimed to be the 360 Degree Space Matrix, which was intended to be compatible with Dolby Pro Logic II, but had separation even higher than most PL II decoders. It also did a phenomenal job of decoding QS-encoded material, and really rocked with stereo tapes and CD's. It was installed in a 1986 Honda Civic hatchback, with a Soundstream 308 head unit, Precision Power 4200 amp, MB Quart speakers in the doors, and JL Audio 6,5" speaker boxes in the hatch. Didn't need a subwoofer!

 

[par4ken]

Sadly another unit that didn't come to fruition. I wanted a Tetrasound car decoder so bad, from the second that I saw the magazine advertisement!

Some years ago I picked up a Gavotte off eBay, It was listed as the last one (out of three) available so I jumped on it. Shortly afterward the seller had three more up for sale! I still have it but never mounted it in a vehicle, just tried it out at home. Very much like the Involve, It realy needs a pre-synth circuit to throw more sound to the rear. It has a switch to reduce separation in the rear, in use the lower separation setting sounded better on my bedroom system but it was better off on the main system.

I also have a Rocktron Circle Surround car decoder that I use in the vehicle which is very similar in operation to the Gavotte and it can throw more sound to the rear.

I suspect that the availability/supply of Tate chips started to dry up and so the move to an RM based system of his own design. Then came the unholy alliance with Dolby surround!

 

[Steve Bruzonsky]

About 94 -98 I had a Citation 7.0 SSP, with Jim Fosgate's 6-Axis processing to expand stereo to multi-channel. At the time, it was simply amazing. I got to meet Jim at CES back about 2000 when he was demoing the Fosgate tube SSP with 6-Axis! Of course, the Citation 7.0 was the very best analog SSP ever made. I moved in 1998 with Dolby Digital and DVD onboard to the Theta Casablanca SSP platform, and after about 20 years moved into the Trinnov Altitude 32 SSP. But 6-Axis may be gone but never forgotten. It was amazing!

 

[jaybird100]

Sadly another unit that didn't come to fruition. I wanted a Tetrasound car decoder so bad, from the second that I saw the magazine advertisement!

Some years ago I picked up a Gavotte off eBay, It was listed as the last one (out of three) available so I jumped on it. Shortly afterward the seller had three more up for sale! I still have it but never mounted it in a vehicle, just tried it out at home. Very much like the Involve, It realy needs a pre-synth circuit to throw more sound to the rear. It has a switch to reduce separation in the rear, in use the lower separation setting sounded better on my bedroom system but it was better off on the main system.

I also have a Rocktron Circle Surround car decoder that I use in the vehicle which is very similar in operation to the Gavotte and it can throw more sound to the rear.

I suspect that the availability/supply of Tate chips started to dry up and so the move to an RM based system of his own design. Then came the unholy alliance with Dolby surround!

There were two models of the Gavotte. The first model had a two-channel input, and a dash-mounted rear level control. I turned up the rear input level on the amp to allow me to have the ability to drive the rears a little more, using the level control on the dash to fine-tune the level. The Gavotte II was an upgrade when I changed to a head unit with front-rear preamp outputs. The fader on the head unit served for front-rear balance. I wish I could do something like it in my current car!

 

[MikeWiz]

Odd, who would fake a Tate schematic? The basic audio circuitry is not rocket science. The magic is done with the DES chips helped along by the interface circuit. The interface (Q8) "Directional Control Circuit" is simply shown as a block, no details. I guess that Jim didn't want that secret let out!

I always wondered why he chose to use the TL084 op-amp when the lower noise TL074 was available for only pennies more. In any case better op-amps can be simply plugged into the sockets. The unit also uses the very common 4066 analog switch.

The only unobtainium parts are the DES chips. The Directional Control Circuit (Interface) would also be problematic should it ever fail, In addition to having no documentation I understand that portion of the board is encased in epoxy.

Good news on the Fosgate Front. We have acquired all his prototypes and finished products, as well as about 10 drawers of schematicsand other notes. Hoefully some Tate 101-A documentation will be in there. Myself and Richard McLean are beginning the process of scanning these on large format scanners.

 

[MikeWiz]

For those interested here's some more info on Shadow Vector from Lyn Olson:

https://positive-feedback.com/audio-discourse/shadow-vector-emerges-from-the-shadows/
Some of this over laps his posts on QQ but there are some new points included. It's great that Lynn & Steve have made some good on line knowledge about their product designs. Too bad Jim Fosgate never did. Or maybe @MikeWiz knows some secret links???

I don't know of any secret links, but we have finally acquired his prototypes, finished products and about 10 drawers full of schematics and other notes. I hope maybe notebooks. And of course the few conversations we had about postive feedback.

 

[jaybird100]

Sadly another unit that didn't come to fruition. I wanted a Tetrasound car decoder so bad, from the second that I saw the magazine advertisement!

Some years ago I picked up a Gavotte off eBay, It was listed as the last one (out of three) available so I jumped on it. Shortly afterward the seller had three more up for sale! I still have it but never mounted it in a vehicle, just tried it out at home. Very much like the Involve, It realy needs a pre-synth circuit to throw more sound to the rear. It has a switch to reduce separation in the rear, in use the lower separation setting sounded better on my bedroom system but it was better off on the main system.

I also have a Rocktron Circle Surround car decoder that I use in the vehicle which is very similar in operation to the Gavotte and Gavotte ithcan throw more sound to the rear.

I suspect that the availability/supply of Tate chips started to dry up and so the move to an RM based system of his own design. Then came the unholy alliance with Dolby surround!

The Gavotte, in both versions, was fully compatible with Dolby Surround. I had some Dolby Surround CD's, when I had the surround system in my car, and they sounded fantastic in that small car. There was separation across the rears, as there was up front. With nothing like the Gavotte available now, I'd love to see Involve move forward on a car version of the Surround Master. In fact, the current model could be used in a mobile setup, but a 12V to 9V power adapter would be needed. Can you imagine how that would sound?? (drooling)