Audio Precision ATS Discussions

[laatsch55]

1 and 3 being shield and ground?

 

[mondialfan]

Yes, thats how the AP manual specs it is for XLR - RCA converter cables to have Pin 1 tied to shield and Pin 3 tied to the signal ground (not shorted to pin 1), however most cables or XLR - RCA adapters that you buy online have those 2 pins jumpered right on the XLR connector which meets the normal XLR - RCA wiring spec. I need to pick up some well shielded two conductor wiring and remake the cheap cables I have.

 

[laatsch55]

I spent two weeks and two handfuls of XLR connectors making cables when I first got mine. From two conductor shielded to some mic cables. When I redo some of them, itll be Mongami cable...

 

[mondialfan]

I ran quick test tonight, Internal GenMon vs a high quality XLR cable vs my el-cheapo XLR > RCA converter cables. I included the plot of it, the primary settings for the test are in the header. I could only run the RCA cable test from 20Hz - 50kHz due to the high output voltage setting so you'll notice the yellow line stops short of the others.

I was surprised that the good quality XLR cable is a nearly exact overlay for the internal Gen Mon test. I expected at least a slight difference. The XLR > RCA adapter cable fared better than I expected but I'll have to rewire those adapters soon.

 

[laatsch55]

What is it about the area around 20 K. Before and after 20K or there abouts it's less, just something I've seen in the paqst.

How are you generating that plot?

 

[mondialfan]

The area's at 2kHz and 20kHz are where the freq range is switching, there's also a step at 200Hz but its not really visible. I see the same thing with my old analyzers, on my Amber 3501 when I switch from 10 X 100 to 1 X 1000 even though its the same frequency theres a jump in distortion.

The software I'm using is APWIN and I'm running it on an old Dell Win98SE laptop.

 

[laatsch55]

How are the laptop and analyzer communicating?

 

[mondialfan]

I'm using a parallel port on the laptop to communicate with the APIB input on the AP S1. I think with an ATS1 or P1 you will have to work with the GPIB bus and I don't believe APWIN will work with that. Do you have a means of exporting the data off of the ATS, ie. a floppy?

 

[laatsch55]

I dont know, I'd have to check. I print numeric tables and graphs, but it would be nice to overlay as in your plot.

 

[mondialfan]

I know that AP had designed the early ATS to be run as an HP8903 emulator, so it would seem that you should be able to get the numeric data off of the GPIB port. I have to wonder if a program like P. Millets 8903 control program could be adapted to operate the ATS and P1 via GPIB.

 

[laatsch55]

Way beyond my pay grade bud. I only understand about 1% of what the AP can do anyway.
Are you the guy that put the Acurus upgrades together?

 

[laatsch55]

Mine is an ATS-1DD, manufactured in March of 2000...with a pretty high serial number..

 

[laatsch55]

Come to think of it there are some BNC export Jack's on the back. One for the generator and one for post processing of the inputs and a 3rd tapped pre processing of the input.

 

[BlazeES]

That's correct. AP does do HP8903 emulation, certainly on a ATS-1 Access 96k like Lee has.

Here's the long and short of it with respect to PC plots and results -

The GPIB bus has the full compliment of control and data acquisition commands, so if it can be measured, it can be automated.
Hooking up a computer and using either Matlab or NI software is a walk-in-the-park for those experienced in that arena.
Obviously you need all the bus-chain stuff to make this work, like the cable and host-side GPIB board and the software.
AP uses this level of automation to perform their test & calibration routines.

The problem lies in the nice, pretty output i.e. the graphing side of it.
Grabbing data from the device registers via GPIB results in raw tables or listings.
The candy coat part of it is taking those data-sets and converting them into graphs with Microsoft Excel macros or lab software plugins.

 

[laatsch55]

This is exactly why I started this thread...good stuff...

 

[BlazeES]

On a side note, got word from John that my box is done. He mentioned that one thing AP can no longer support is bad switch assemblies. No more parts. And those momentary bubble switches are super delicate inside, so they've tried in the past but no longer attempt cleaning them. He told me that my switches are fine but the 'soft' ones are aging a bit and require more pressure than normal to actuate. So in a nutshell, 'passing self test' isn't the only thing to watch out for if someone is on the hunt for one of these, out in the wild.

Here's an internal shot I took before sending it in. Relatively clean inside considering it's a 1996 build.
A little soot here and there on the ribbons ... but no bigs.

 

[laatsch55]

Wow, I would have expected more"stuff" to be in there.. ...

 

[laatsch55]

Obviously I haven't opened mine up yet...

 

[laatsch55]

I wonder how much of what Jer has done could be used here in plotting? Jer?

 

[BlazeES]

Wow, I would have expected more"stuff" to be in there.. ...

Yeah, and I inspected the heck out of this thing and can't quite figure out the air-flow pattern. The top and bottom covers screw down tight as all get up, no gaps at the seams and there are no breather holes or slots to speak of - so I'm guessing there is some inlet flow from the front head - maybe by way of the foam around the display and the jacks? No idea. Kind of weird.