I got an old Audio Precision System One off ebay. Probably the lowest model, it only has one analog channel, a serial port, and the AP bus. I found out only the oldest version of software (that runs under DOS) supported the serial port. The last release of software that can be used runs under Windows 98. There are some former AP employees selling little lunchbox computers on ebay with a driver that will allows the printer port to be hooked to the AP bus with a special cable. So now I can talk to the box and it seems to work. Figuring out the software without any documentation is a pain but, I'm slowly getting up to speed.
One thing I would like to do is create those nice graphs like Nelson Pass does of distortion vs output power for a power amp. The only options I can find for the horizontal axis is oscillator output, either voltage or power (mW). I suppose I could use an attenuator on the oscillator so that 1mW of oscillator power equals 1W of output power or something to that effect. I really don't want to have to dig into their scripting language.
Do newer AP systems create these graphs without all the hassle?
One thing I would like to do is create those nice graphs like Nelson Pass does of distortion vs output power for a power amp. The only options I can find for the horizontal axis is oscillator output, either voltage or power (mW). I suppose I could use an attenuator on the oscillator so that 1mW of oscillator power equals 1W of output power or something to that effect. I really don't want to have to dig into their scripting language.
Do newer AP systems create these graphs without all the hassle?
Hint: If you register at AP.com (free), and go to the 'Legacy' page (do a search) you can download all kinds of documentation, app notes, user guides and even service manual.
Then there's the vintage AP user group at LinkedIn, with lots of friendly people including ex-AP engineers.
Didn't think about that, ha!
jan didden
Then there's the vintage AP user group at LinkedIn, with lots of friendly people including ex-AP engineers.
Didn't think about that, ha!
jan didden
I'm registered on the AP site. Sifting through many megabites of info takes a lot of time and I'm not going to print out a 300+ page manual. Went through many of the ap notes, didn't find anything about plotting power as the horizontal axis. The original System One operators guide uses the DOS version of the control program (S1.exe), it's a little different. There's a book by Metzler that explains all the different units used in measuring audio. Very usefull.
Two things were holding me back. One, you have to double click on the sweep menu to get the "large version" to display. That's where the X-Y button is located. Second, because my box only has one channel, I thought "Data 2" referred to the second channel. I haven't seen anywhere in any manual where it talks about a single channel analyzer. I just had to sit down and play with the box to see how it works and try to learn from the help files.
Now I need to get proper test leads together and clean up the amp I'm building so there are not so many clip leads. Get rid of those wavy lines around the 1 watt level.
Two things were holding me back. One, you have to double click on the sweep menu to get the "large version" to display. That's where the X-Y button is located. Second, because my box only has one channel, I thought "Data 2" referred to the second channel. I haven't seen anywhere in any manual where it talks about a single channel analyzer. I just had to sit down and play with the box to see how it works and try to learn from the help files.
Now I need to get proper test leads together and clean up the amp I'm building so there are not so many clip leads. Get rid of those wavy lines around the 1 watt level.
I had forgotten what I paid, so I looked it up. The price seemed high, (it was a few years ago). Then I looked on ebay to see what's on there now. It was less than any of the AP boxes (not including switchers) on ebay (USA) right now. I had no idea you could spend $20K to get the latest and greatest. I have a Tektronix distortion analyzer and low distortion oscillator. They are from the 80's, designed by the same guys that started AP. The AP box just makes it easy to plot those graphs and store them. I'm not into the ultra low distortion, but it's nice to look at the analyzer output to see the harmonics. I guess the next step would be some way to do FFTs.
Attachments
sorry to wake this thread up again ... but did anyone find a decent solution to connect one of the older APs to a PC without a GPIB bus ? I have a Portable 1 and right now i'm logging readings into an excel and drawing charts which is an amazing pain. I went out and bought a aprallel port laser printer (not too easy to find these days) and plugged in but i get gibberish out regardless of what emulation I select on the printer and /or on the AP. I researched it and theres someone that sells a generic solution for parallel port to data solution but no word on whether anyone has tested and found that it works on an AP.... Loudthud, in your first post you mentioned "There are some former AP employees selling little lunchbox computers on ebay with a driver that will allows the printer port to be hooked to the AP bus with a special cable. So now I can talk to the box and it seems to work. Figuring out the software without any documentation is a pain but, I'm slowly getting up to speed." ... would this work for me you reckon ? thanks!
I have THREE older AP SYs1's I am tryingto work with. Currently one is running on an old 286 computer with the dos software and it has a bunch of batch files for running specific test's.
I bought the Parallel port cable kit and have win 98 running on a newer PC and have that running with a 2nd Sys1 just fine.
But now I need to figure out how to import the old dos SYS1 files into the newer 98 machine? and not only is it a PITA but i can't get it to work no matter what I do. and I have have found a couple of pages that explain how to do it on the AP site (yes I'm registered) but it still doesn't work.
I need to find this linked in AP group you mentioned or any other AP group or anyone that has done this and understands how to make it work!
Zc
I bought the Parallel port cable kit and have win 98 running on a newer PC and have that running with a 2nd Sys1 just fine.
But now I need to figure out how to import the old dos SYS1 files into the newer 98 machine? and not only is it a PITA but i can't get it to work no matter what I do. and I have have found a couple of pages that explain how to do it on the AP site (yes I'm registered) but it still doesn't work.
I need to find this linked in AP group you mentioned or any other AP group or anyone that has done this and understands how to make it work!
Zc
Classic AP Audio Systems Group | LinkedIn
It's a pretty intrusive application but if you click the correct buttons it will give up on trying to interrogate your email contacts when you sign up ( if you do give it up they promise to keep it private however)
I havent quite worked out how to navigate and find stuff without just asking outright and sounding like a total ingrate but this is where the knowledge seems to be.... Happy hunting!
It's a pretty intrusive application but if you click the correct buttons it will give up on trying to interrogate your email contacts when you sign up ( if you do give it up they promise to keep it private however)
I havent quite worked out how to navigate and find stuff without just asking outright and sounding like a total ingrate but this is where the knowledge seems to be.... Happy hunting!
zc, found these guys - they have two products one a standalone minicomputer for older AP and another is a interface kit... Sound Logic Mini Computers
The Mini Computer is out of stock, the last time we asked.
On the top of the webpage
Sound Logic Mini Computers
"NOTICE: We are currently out of stock. We are looking for a suitable replacement Mini PC and after testing we will make the new units available. "
Patrick
On the top of the webpage
Sound Logic Mini Computers
"NOTICE: We are currently out of stock. We are looking for a suitable replacement Mini PC and after testing we will make the new units available. "
Patrick
Here's two problems I've run into.
1) If you put the PC to sleep and try to resume, the new data you plot looks corrupt. In the update notes it says the problem is fixed. NOT! I finally got an answer from Nelson Pass. If you have the Append box checked, the new data is screwed up. You have to uncheck Append, then plot new data. Nelson called it a PITA.
2) A number of the pdf files for the manuals from AP.com don't seem to be compatible with the Acrobat reader that runs under Windows 98. I don't have a way to get the Win98 box online, and I don't expect much support from Adobe. So I have to look at the pdf files on another computer.
I refuse to go on LinkedIn. They sent me too much spam trying to get me to join.
1) If you put the PC to sleep and try to resume, the new data you plot looks corrupt. In the update notes it says the problem is fixed. NOT! I finally got an answer from Nelson Pass. If you have the Append box checked, the new data is screwed up. You have to uncheck Append, then plot new data. Nelson called it a PITA.
2) A number of the pdf files for the manuals from AP.com don't seem to be compatible with the Acrobat reader that runs under Windows 98. I don't have a way to get the Win98 box online, and I don't expect much support from Adobe. So I have to look at the pdf files on another computer.
I refuse to go on LinkedIn. They sent me too much spam trying to get me to join.
Late to this party, but I thought this might be of some help to fellow Audio Precision System One owners:-
Yesterday I powered up one of my AP1's for the first time since retuning from China 3 years ago, only to find a problem with THD+N, it was jumping about from 0.003% to 0.1% 20Hz-22KHz (GenMon)... So I put it to once side and powered up a second unit only to find other problems and then with a 3rd unit! Yesterday was a REALLY bad day.
So I spent the day looking into the issues on these units - all would fail the selftest routines (the little "Red" tick box in APWIN 2.24), THD, Level and Phase depending upon unit.
The THD problem was due to Electrolytic capacitors leaking on the PCB manufactured by NIC Corporation NRWA series 25V / 47uF Dark Brown Body.
NIC Components NRWA Series
You need to look closely at every PCB in the unit as there are two types manufactured by NIC, Dark Blues types which don't appear to suffer from the issue, but I remove 23 "Dark Brown" Caps from my unit, EVERYONE of them had leaked or showed signs of leakage.
https://dl.dropboxusercontent.com/u/86116171/AP1 Cap1.JPG
https://dl.dropboxusercontent.com/u/86116171/Section AP1 Cap2.jpg
https://dl.dropboxusercontent.com/u/86116171/AP1 Cap2.JPG
https://dl.dropboxusercontent.com/u/86116171/AP NIC NRWA bad Caps.jpg
Unfortunately the electrolyte had almost eaten though the Copper tracks on one of my DIS boards, lucky I caught it just in time.
Basically after cleaning the PCB and replacing all the caps resulted in stable THD readings, but I had to readjust the Null and Level pots to achieve a deep notch (about -115dB to -120), slightly lower the the second harmonic component.
I'm not sure what THD+N at 1Vrms, GenMon, 20Hz to 22KHz is normal, but I was able to tweak 1KHz to 0.00035% (non Wtd) , this then drifted to 0.00045% when the covers where replaced.
After setting the Gen Level, Tweaked the Null and Level Pots in each DIS board Adjusted the Phase pot on one unit, I was able to get all units pass the selftest - WHEN WARMED UP, when first powered up non would pass - it takes about 10 minutes warm up period before the plots on the selftest start to appear they will fit within the Pass / Fail template "Masks".
I say all passed, but one unit would still fail the “Flatness test” at 20Hz, limit is 0.03dB, it failed at -0.035dB… I’ll not waste time hunting this down unless anyone has any ideas?
I also had to adjust the 20MHz Reference (really a poor design the clock frequency all over the place), I also had to adjust the 100Hz, 1KHz, 10KHz & 100KHz Gen frequency pots on the Gen boards, these had drifted on all units.
AP provide the full Calibration routes for the AP1 which I tried in the DOS box on a Windows XP machine but the program was SOOOO primitive (I remember DOS days, but NOTHING this primitive) I could not find the directory that had the procedure / .TST files saved and not knowing what I was really doing escaped back to the safely of the WinXP GUI and stroked my Trackball / Mouse thanking him that the DOS days are long past!
Lastly, a problem I’ve seen in China where one unit on a production line puffed out smoke and flames – the crimping connector on the White Cable from the transformers secondary should be soldered directly to the PCB as the connection overheats and browns / melts the plastic connector housing, ALL my units suffered from the same issue – its going to fail, so take the time to fix it when your replacing the caps.
Yesterday I powered up one of my AP1's for the first time since retuning from China 3 years ago, only to find a problem with THD+N, it was jumping about from 0.003% to 0.1% 20Hz-22KHz (GenMon)... So I put it to once side and powered up a second unit only to find other problems and then with a 3rd unit! Yesterday was a REALLY bad day.
So I spent the day looking into the issues on these units - all would fail the selftest routines (the little "Red" tick box in APWIN 2.24), THD, Level and Phase depending upon unit.
The THD problem was due to Electrolytic capacitors leaking on the PCB manufactured by NIC Corporation NRWA series 25V / 47uF Dark Brown Body.
NIC Components NRWA Series
You need to look closely at every PCB in the unit as there are two types manufactured by NIC, Dark Blues types which don't appear to suffer from the issue, but I remove 23 "Dark Brown" Caps from my unit, EVERYONE of them had leaked or showed signs of leakage.
https://dl.dropboxusercontent.com/u/86116171/AP1 Cap1.JPG
https://dl.dropboxusercontent.com/u/86116171/Section AP1 Cap2.jpg
https://dl.dropboxusercontent.com/u/86116171/AP1 Cap2.JPG
https://dl.dropboxusercontent.com/u/86116171/AP NIC NRWA bad Caps.jpg
Unfortunately the electrolyte had almost eaten though the Copper tracks on one of my DIS boards, lucky I caught it just in time.
Basically after cleaning the PCB and replacing all the caps resulted in stable THD readings, but I had to readjust the Null and Level pots to achieve a deep notch (about -115dB to -120), slightly lower the the second harmonic component.
I'm not sure what THD+N at 1Vrms, GenMon, 20Hz to 22KHz is normal, but I was able to tweak 1KHz to 0.00035% (non Wtd) , this then drifted to 0.00045% when the covers where replaced.
After setting the Gen Level, Tweaked the Null and Level Pots in each DIS board Adjusted the Phase pot on one unit, I was able to get all units pass the selftest - WHEN WARMED UP, when first powered up non would pass - it takes about 10 minutes warm up period before the plots on the selftest start to appear they will fit within the Pass / Fail template "Masks".
I say all passed, but one unit would still fail the “Flatness test” at 20Hz, limit is 0.03dB, it failed at -0.035dB… I’ll not waste time hunting this down unless anyone has any ideas?
I also had to adjust the 20MHz Reference (really a poor design the clock frequency all over the place), I also had to adjust the 100Hz, 1KHz, 10KHz & 100KHz Gen frequency pots on the Gen boards, these had drifted on all units.
AP provide the full Calibration routes for the AP1 which I tried in the DOS box on a Windows XP machine but the program was SOOOO primitive (I remember DOS days, but NOTHING this primitive) I could not find the directory that had the procedure / .TST files saved and not knowing what I was really doing escaped back to the safely of the WinXP GUI and stroked my Trackball / Mouse thanking him that the DOS days are long past!
Lastly, a problem I’ve seen in China where one unit on a production line puffed out smoke and flames – the crimping connector on the White Cable from the transformers secondary should be soldered directly to the PCB as the connection overheats and browns / melts the plastic connector housing, ALL my units suffered from the same issue – its going to fail, so take the time to fix it when your replacing the caps.
Last edited:
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