Audio Precision APIB ISA Card

[Audio1Man]

This will only work in DOS

In my opinion the simplest way would be to copy the schematic from the S1 service manual (maybe without the RS232 interface).
It consist of only about a dozend TTL chips which are still available.
I am sure someone here could make a good picture of the card so that the layout could be done semiautomatic 🙂

Udo

This will only work in DOS.

Duke

 

[nejo]

In my opinion the simplest way would be to copy the schematic from the S1 service manual (maybe without the RS232 interface).
It consist of only about a dozend TTL chips which are still available.
I am sure someone here could make a good picture of the card so that the layout could be done semiautomatic 🙂

Well, a few things came to my mind when planning this little project:
1/ A couple of the logic chips are no longer stocked by the main distributors,
2/ An exact copy of the PCB layout would infringe AP's copyright, of which I have no intention of doing so,
3/ Maybe one day if I can understand what is needed to support ApWin I can reconfigure the CPLD with the necessary extra logic.

Neil

 

[nejo]

So after a couple of evenings fixing bugs in the Verilog code, it all seems to be working. I can run S1.exe on my little industrial 486 PC running DOS5 and hooked up to the SystemOne. I've put some pictures on my blog:
cesyg: Analyze This!

Neil

 

[Audio1Man]

Hi Neil

Great work, Please Email me as I have some information for you.
duke.aguiar@ieee.org 🙂

 

[1audio]

Nice work. On the site you mention using Coax cables. Are you using XLR-BNC adapters? If so probably one of the two signal lines is floating. Fix that and you should get at least 6 dB improvement.

 

[nejo]

Hi Demian,

Nice work. On the site you mention using Coax cables. Are you using XLR-BNC adapters? If so probably one of the two signal lines is floating. Fix that and you should get at least 6 dB improvement.

No, for some reason my SysOne has isolated BNC connectors for the gen outs and analyser ins, instead of the more usual XLRs. I'm guessing this was a factory option rather than a field modification. And yes they are ordinary BNCs, not those weird triax types.

Cheers,
Neil

 

[nejo]

Small update: everything seems to be working except the card detect at startup, but specifying the card address with the /I option and it works fine. Self test indicates the internal THD+N is about 0.0014% across the audio band so I think it's a happy bunny.

Time to put it to some use!

Neil

 

[nejo]

By the way, if anyone wants a set of isolated BNC sockets suitable for a System One then PM me. I don't need them and it's a shame to bin them.

Neil

 

[nejo]

Quick update on this issue: after some prodding from a fellow AP enthusiast I finally sorted out the auto-detect support on my interface card. Now S1.EXE can automatically find my interface card without having to specify its address with the /I option.

One less thing to worry about!

Neil