Hi, sorry you’re having problems - I can’t pretend to tell you that I know precisely what’s wrong with your DT but from what you’ve described I can tell you what stands out to me and hopefully it will give you more to go off of than where you’re standing now - first is that the audio through overbridge is fine - sounds like the problem is on the hardware side, meaning somewhere between the output stage for the audio and the analog potentiometer itself. Your assertation that both with headphones and the L/R outputs the same behavior is present leads me towards the potentiometer being the culprit since all final gain on the hardware side is regulated by the DT analog main volume.
Your statements about pricing for repair lead me to the conclusion that you are no longer under warranty. In order to confirm beyond a shadow of a doubt if the problem is a software bug or an issue related to the potentiometer will require you or someone you trust to do some testing to see if there is a spike in resistance between the pot terminals when the volume increase occurs, it would actually appear as a drastic dropout in resistance because the wiper inside the pot going across the resistive strip is what regulates the volume level and if there is no more resistance - it is basically an open circuit meaning full volume / high gain.
It may prove to be less expensive to pay someone independent of Elektron (but still a certified/qualified professional) to replace the volume pot than it is to have it properly diagnosed, however that is not a guarantee of a repair. If you want a guarantee of a repair, send it to Elektron for diagnosis and repair. A volume pot (if that is the culprit) is $4 USD plus their time and the cost of shipping your digitakt to and from their service center and you will wait ( it sounds like ) 2-3 months - while that seems like a long time, it’s not a cheap synth and may well be worth that cost if you enjoy using it.
You could alternatively order a volume pot from elektron care for $4 USD and probably $15 shipping from elektron, as it can be ordered and shipped directly to you if you request that using your support ticket. If there is someone local to you who can do the repair and save you the cost of shipping and waiting, and the ultimate cost will only be an hour or 2 of service this may be the preferred option. The bench rate for labor at an electronics repair professional will be +/- $80 an hour, elektron’s quoted repair rates are within reason. If you know someone who is not a professional but qualified, it may be cheaper but someone who guarantees their work is priceless.
If you want to get closer to confirming whether the issue is with the physical control (volume potentiometer) and not a behavior shared with all volume related changes, Set a level that is not clipping/distorting through the roof and then adjust the channel volume using the encoder below the main volume instead of adjusting the main volume itself. If you can adjust the volume of individual channels up or down from where they are currently without any huge jumps in level or similar behaviors to the issue you’ve described in your post, then we see it is not all volume changes but specifically volume chages made with the main volume that are the issue, and that then leads a bit closer to the hypothesis that the volume pot itself could be the issue. I am not going to guarantee you anything one way or the other, you will have to decide the best course of action for yourself. Elektron can definitely repair the issue, but if you have a strong belief it is an issue related to the hardware (pot) and you have a multimeter or know someone who can test the resistance between the terminals while the volume is being turned you can get a pretty clear diagnosis but that will also require you to open the machine and if you aren’t comfortable or experienced with something like that, seek a professional.
Mostly I would say don’t do anything rash, be patient, and good luck. I’m sure it’s frustrating and if you’re uncertain of a good course of action it makes it worse. One thing that is not a great option but IS a workaround is you could buy an inline headphone amplifier (attenuator) for $20-30 on amazon and use that to adjust your level for the headphones however that would not be a very good workaround when it came to the main outs. If you work strictly with overbridge it also sounds like it won’t be an issue, but if that were what you wanted you wouldn’t be asking about it in the first place. After you test the channel volume and confirm whether or not it has any indication of similar behavior to the master volume, you can possibly report back here about it but mostly this is going to come down to professional diagnosis because I’m far from a professional, I’m just trying to give you some facts and help clarify your options. I don’t personally think this is software related but it’s impossible to know without a thorough diagnostic.
If you have not yet run the self test mode by holding the function button during start up to get to the pre-boot menu, I would also suggest you try that.
