Topic: RME adi-2 DAC fs not speaking well to Pathos Aurium

Hello everyone, I am hoping that someone might be able to offer a fix to my issue. I have been enjoying fantastic sound, and then all of a sudden something has happened to make the bass all distorted. (Probably me pressing something I shouldn't!)

With anything acoustic it is not so bad, but any bass, there is lots of noise and whereas before I could listen for several hours, now I can only stand a few minutes before I get a headache and have to remove my cans.

Al of the connectors are fully secure, my headphones have been tested as working with another device, and the amp tubes are working. I am pretty sure the issue is caused by the balance of volume between the DAC and headphone amp. I have done a reset on the DAC and also just discovered if I have the DAC set at full volume (6 dBr) and the headphone amp volume at zero, then slowly increase the volume on the amp, then noise and distortion is really exacerbated.

If I turn the DAC volume down to -20 dBr it is a lot better, but I still don't think the SQ is optimal. I have heard that there is a mathematical equation to work out the correct volume settings, using the comparative power/specs of the two devices.

Thanking you in advance! Steven

2 (edited by Audio AG Support 2024-06-17 13:23:47)

Re: RME adi-2 DAC fs not speaking well to Pathos Aurium

Your headphone amp can only handle +12dBU on the XLR input according the Data sheet.
You cannot go higher with the reference level on the DAC as +7dBu (7+6(XLR)= +13dBu).
You can choose to set the reference level not to "auto" but to +7dBu. You can always set the volume with the headphone amp.
Now you are probably overloading the headphone amp.

If you want to know more about the volume control on the DAC, please read page 67 form the ADI-2 DAC manual.
dBu reference level calculator:https://sengpielaudio.com/calculator-db-volt.htm
Specs from your headamp https://www.projekt-akustik.de/mediafil … tt-ENG.pdf

Regards,
Audio AG Support

3 (edited by KaiS 2024-06-17 15:16:18)

Re: RME adi-2 DAC fs not speaking well to Pathos Aurium

You don’t even need any calculations:

• Set your Aurum’s volume dial to 14 o‘clock position, the back’s Gain at 3/4 clockwise dial position, and all bottom micro switches to “On”.

• Switch on ADI-2‘s “Auto Ref Level“.
If you see ADI-2’s volume shown in dBr, not just straigh dB without “r” this is already the case.

• With ADI-2’s Volume, dial a comfortable listening level.

That’s it.

In doubt, you can even countercheck if the ‘phones connected directly to ADI-2 do sound clean.