Input Preamp gain (PGA Gain)

Hi there,

I’m trying to set the PGA gain (the input preamp gain I assume) to any other value than +21dB.

On the V5 itself I went into :

Mix -> Level -> Ctrls#2
Level is currently at +21.0dB
Change value to 0.0dB
Nothing changes in the sound.
Get out and return in this same menu and the value is back to +21dB.
Tried many permutation of this maneuver to no avail.

On the webconf I went in
Hardware -> Audio -> [...] button
Then checking both PGA Gain Left and Right to 0.0dB
Pressed"ok then save
To which after a while returned :
Zynthian needs to reboot to apply your changes!
and promptly clicked the nuclear nuke inspired REBOOT NOW! button.

After reboot. No change whatsoever.

Redid the very same webconf adjustment (twice now) and after booting the input gain was finally audibly 20ish dB lower in volume.

But then I went in the level menu again of the V5 itself and just looking at the menu made it jump to PGA +21.0dB and bam, the volume changed back to an audible 20dB higher.

I search for this issue but neither the wiki nor the discord search engine turned fruitful.

Any hints ?

Are you using latest stable image?
There are some fixes to the audio levels screen in the testing branch.
Perhaps you could try with the testing SD- image.


Loaded image 2311 and yes, Input gain is working as expected directly on the V5.

I is a now a very happy person.

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The latency in definitively lower or am-I hallucinating ?

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humm, the gain still changes (audibly and in the UI) for no apparent reason. I have not yet figured how to reproduce reliably… Can we lock the gain and level ?.

Transcript :
So, I’m in the audio level [menu]. And if I [just] touch the level of the input, it “jumps” to a high level [even if] the gain is still at zero [in the interface]. And if I touch it [the gain], I goes really to 0.0dB and If I go back and just touch the volume, it jumps right up.

I’m speaking in an SM58 the whole time.

Still very weird here,

What is supposed to be the difference between Input 1 Level range(0…100) and the Input 1 Gain ranging from -12dB to 40db.

In normal audio consoles, there is the “hardware” gain and digital gain and I figure that was the case here.

Steps to reproduce

  1. I open the level menu and set the level to 15 and the gain to 0dB.
  2. I then check by moving from the Ctrls#1 to the Ctrls#2 submenus multiple times that the settings are still level 15 and gain 0dB
  3. Get out of the Level menu (say pressing once on OPT)
  4. Get back inside the Level menu only to find that the levels changed. In this case to level 9 and gain 0dB

What is the matter with you Zyn ? Speak to me !

Running the freshly updated testing :

zyncoder: [testing (768df83) ]
zynthian-ui: [testing (e2f6988)]
zynthian-sys: [testing (a9a3f7c)]
zynthian-data: [testing (1321e5d)]
zynthian-webconf: [testing (20cd581)]

So, just to clarify, the problem does occur in current testing, and not in stable? or…?


Hi @PeterLuck !

I will take a look ASAP. Thanks for reporting …

Best Regards

Hi @PeterLuck !

I reproduced the bug and now it’s fixed. Well, indeed there were 2 issues:

  • threading problem when going back and entering audio levels again

  • “ADC” and “PGA Gain” controls are repeated in the ALSA driver: they are the same parameter exposed in 2 different ways, dBs and %. So i removed one of them (ADC) from the audio level’s config to avoid further confusion.

After updating (testing branch), it should have been removed and the threading issue, must be fixed.
Please, confirm.

Best Regards,!