Dolby cat 43

[ubxf]

Hello,
I just found an old Dolby cat 43 remote pulled out of an Otari console. I remember using them 30 years ago during my analog mixing days If I remember correctly the remote was plugged in a Dolby A card (cat 22) then there was a card plugged in a dolby rack where the cat 22 card normally sits. Are there schematic or pinout infos available, I looked for a fair amount of time and didn't come up with anything yet. Any advice would be appreciated.

 

[ubxf]

 

[ubxf]

It looks like the Dolby 361 is providing power 24V and serves as audio interface (transformer in/out) . Would it be possible to just use the 43A and cat22 card if 24v was fed to it or is the 361 necessary for decoding the dolby processing ?

 

[Evertide]

CAT 22 is the Dolby part , 361 interface to the outside-world ( power , audio transformers ) , 43A control..

 

[ubxf]

Thank you, so the 43A/cat 22 need only power and possibly a jumper/switch to simulate play mode and NR in ?
Do you happen to know the pin out of the XLR between 43A and 43B ?

 

[Evertide]

Look for the " Dolby 361 Noise Reduction Instruction Manual " , it has most info and schematics on the 361 and 22...

 

[ubxf]

yes that is the one I posted above, I didn't see anything in there about cat 43 or cable pin out. From the 2 schematics I should be able to figure it out but if someone had the pinout it would have been nice.

 

[ubxf]

Here is the manual with a better resolution

 

[ubxf]

 

[ubxf]

 

[ubxf]

I traced the pinout for the 7 pin xlr connected to the 43A to the Edge connector and tried to cross referencing to the cat 22 schematic
1- 16/17 < 0 V>
2 nc
3 nc
4- 15 <+24 V>
5- 12/21 <line out>
6- 4
7- 2

But I don't get where the input might be, from the schematic it should be 10 but no contact between 10 and xlr

 

[Evertide]

7 - 2 < Meter Signal >
6 - 4 < Output No 2 >

Sure 2 or 3 don't have a broken of wire ?

 

[ubxf]

I'll check but I have 3 units and they all read the same, it would be a weird coincidence

 

[ReDolby]

There are a few parts to the Cat 43 system. The NR frame (Model 361), the Cat 22 NR module, the Cat 43A (which you have) and the Cat 43B. Please see the attached block diagram (mostly hand drawn) which shows the interconnections between these parts. The majority of the work is done by the Cat 22 and the Cat 43A, and thankfully the Cat 22 plugs into the Cat 43A. The 361 provides power, input/output level controls, transformers, and a meter. Note that the Cat 43B is not passive, but an x1 buffer and an x2.2 gain- both can probably be skipped. I think it is possible to make this work with just the Cat 43A and a Cat 22. Also attaching a more complete version of the instructions (though still atypically light).

Hope this is helpful.

 

[Evertide]

On the connector the Dolby used number / lettering :

1 - A
2 - B
3 - C
4 - D
5 - E ( Not used => opening )
6 - F
7 - H
8 - J
9 - K
10 - L
11 - M
12 - N
13 - P
14 - R
15 - S
16 - T

 

[ubxf]

Thank you , this is much appreciated .

 

[samplebias2]

While we're on the subject, does anyone know what that white block/jumper is on the port where the Cat-22 card gets inserted into the fader box?

 

[ubxf]

To make sure the cat 22 card is not inserted backward

 

[samplebias2]

Ahh like upside down ( I always assume it would be inserted with the writing on the rear legible/right side up)

 

[Evertide]

Note that the Cat 43B is not passive, but an x1 buffer and an x2.2 gain- both can probably be skipped. I think it is possible to make this work with just the Cat 43A and a Cat 22. Also attaching a more complete version of the instructions (though still atypically light).

Hope this is helpful.

The buffer is for buffering , i would like it in...

The .2 is for circuit loss , 2 for compensating the amp in 43A , when the threshold pot for this amp is going down , on the 43B it will go up...