QA40x V1.194 pre release

Noticed Matt has just uploaded a new pre release version with some bug fixes and changes.

I’m running it today and so far, I’m seeing fewer ADC overflow messages which I was constantly getting previously. Seemed to be linked to input range switching, even with shorted inputs- I’d figured it was an offset issue, but it seems to be mostly fixed now.

edit: it still happens, but to a lesser extent. pulling the USB lead and resrating solves it for a while.

Changes to the idle mode attenuator settings to prevent the full scale relay glitch at the 7.5 to 7.6dBV step.

Suggest everyone give it a go as any bugs/issues will be found quickly and ironed out faster.

I have noticed ctrl+X toggles between Xlin and Xlog ‘buttons’, but does not change the live display axis on the FFT, whereas actually pressing the buttons with the mouse does. A minor bug.



I found a problem with the Automated Output impedance test- it thinks there is a problem with an incorrect start frequency. Reloaded 1.193 and it ran fine with the exact settings.:

It seems the global start/stop frequency range values are set in the THD settings. So, right click the THD button and set 10Hz as the Start frequency.


Then you can set the start frequency to 10Hz. I had the same problem with upper frequencies- wanting to set above 20kHz until I read the manual…


Page 22
For THD and THD+N, the context menu is as follows. The Measurement Start and Stop frequency is the same as the RMS setting. That is, you set a measurement start and stop frequency globally, and that is used for all measurements that need a measurement start and stop specified.

Hi @Var, @restorer-john is correct. This was a change made to start/stop frequencies in release 1.194 so that the rules are now enforced and it was applied to all plug-ins. I’m still not completely happy with how it’s working because, as you note, it’s a bit cryptic and for someone that is new to the QA403 HW and SW, it’s probably too overwhelming. Maybe the Measurement Start/Stop could be automatically changed? But that too has it’s own issues in that I’m not crazy about something so fundamental being changed. Or maybe the message could be “Value must be >= Measurement Start Frequency (right click on RMS button)” or something similar.

I actually don’t use the measurements buttons so that is not something I would check for. I loaded 1.194 and as long as the THD measurements start frequency is the same as or > than the automated measurements, I am OK. I did not see @restorer-john’s post until I saw yours just now. It is good that I did not do any automated tests in the upcoming video :sweat_smile:

I like the measurements buttons as they quickly toggle the displayed fields much easier than checking the boxes, especially when both channels are active- makes for a neater display IMO. All I would like to see is the buttons to be ‘on’ or highlighted when clicked. Not sure why that isn’t implemented as the other buttons show whether they are activated or not.

I use the save/recall settings so all the displayed fields I want are pretty much there for the measurement I am doing. I think it would be nice if you could drag the measurement boxes around to where you want them to be sometimes :smiley:

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You can rearrange the order of Measurement boxes by clicking the “Hamburger” on a box and dragging it around. For a few examples here, see the red arrows…

I just tried that and to quote Gomer Pyle: “Well I’ll be”… Very cool, thanks.


I noticed in a few posts, Matt is using (probably testing) a new version…


As usual I may be a little slow on the uptake, but in case anyone else is checking this thread, the latest release is already out and is actually Release 1.197 (February 2024)

Enjoy! QA40x release page

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