APx500 starting help

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Hi there,

I borrowed an AP APx515 in order to perform measurements my newly DIY-built headphone amp. I bow my head in repsect to opc!

As I am a new user to the software, I would like to ask you for a little "boost".

Especially with i.e.

  • varying generator levels and
  • graphing output such as Distortion Product vs. Harmonic multiples
I am having a hard time as beginner in this topic.
Maybe you could kindly share a "basic amp measurement" project, so that green horns such as me get a starting boost.



Thank you very much!


Best regards,
LeFish
 
AX tech editor
Joined 2002
Paid Member
If you search at the AP website, there are many app notes and tech notes where they explain test protocols.

Probably the best way to start is to read up in the manual about the difference between 'Bench mode' and 'Test mode'. In Test mode, selecting the test like Distortion in the 'explorer' type list on the left, will automatically set up the hardware for such a test, and you can then set generator levels, output and input impedance levels, frequency range etc. In Bench mode you can manipulate the hardware at its basic level and you probably don't want to start with that.

This is very high performance software and it is impossible to just start to use it, it will take time. But note that you can play with the software even if you don't have the equipment, using it in demo mode.

Have fun,

Jan
 
Last edited:
AX tech editor
Joined 2002
Paid Member
Correction: not Test mode but 'Sequence mode'. Selected at the top right. Then on the left you select the test you want to run.

Jan
 

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The APx-515 only has bench mode if you spent an extra 40% on software options. (You can practically buy an AverLAB analyzer for the same amount as Bench Mode will set you back).

AP does have a youtube channel with a bunch of short videos that can help get you started quickly.

Assuming you are in sequence mode, just click the Add Measurements button and you can see all the different types of measurements available. The Stepped Frequency Response gives you H2 & H3 responses as well as THD+N if I recall correctly.
 
AX tech editor
Joined 2002
Paid Member
I thought so. It used to cost an extra 55% but they finally lowered it. It is free on their other models. I find it kind of a kluge that there are certain measurements that can only be performed in one mode or the other.

Well the hardware is there so you can do any measurement that you can do in the other models in sequence mode. It's just more effort to set it up. Correct?
I think any sequence is just a script that you can always set up yourself if you want. You pay for convenience.

Jan
 
Yes and no. Simple things like looping a test cannot be done in sequence mode. Bench mode lets you sweep parameters that you cannot sweep in sequence mode. I believe SNR and CMRR require sequence mode although there are workarounds to get it done in bench mode. There were other difference too (e.g. Modulated Noise test) but I can no longer recall all of them. I just remember my frustration having to go back and forth and the 10 second lag it took to do so.
 
Maybe I am to blind to see after flipping through the youtube channel YouTube
, but my wish is to generate a graph like

http://www.diyaudio.com/forums/atta...adphone-amplifier-pcbs-thd-vs-output-900r-png

This is varying the actual values of THD over the generating level.

Basically a for-loop over different input levels.

Then the sequence is ideally graphing the output (=THD over generating level).

Probably it's a dumb questions, but maybe you could give me a hint.

Thanks!

Best regards,
LeFish
 
Jan,

I know someone who looked at AP as a possible aquisition. They are profitable but not screamingly so.

Thus their additional charge for extended software may be expensive, but probably needs to be for the small number of users.

There certainly are much less expensive equipment options available with less support.

BTY I am not a fan of AP in general. But that is for other issues.
 
Solution to THD Vs. Generator Level

Hi there,

I finally got it myself.
This measurement is under "Level Sweep".

One can load (add) it as a measurement and then add as a step (=part of a sequence).

attachment.php


Thanks to all!

Beste regards
LeFish
 

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