White Noise in earphones

I also have a Headstreamer (picture below), which is a USB headphone amp. 

With the Headstreamer, the noise is there but it is directly proportional to the windows volume settings. When volume is at 100%, the noise is the same as on the Yulong. But to listen comfortably, the volume is at 3%, and there the noise is very very small (almost none really). This is funny, I read that the recommended settings is to have windows sounds at 100% and reduce the volume in Foobar. If I do that: big noise.

Why is the Yulong producing maximum noise, as it the volume was at 100% even when not connected to a source and with analogue volume set to -60db?

Most likely, the Yulong DA8 II headphone amp section has some self noise. Since the sensitivity of the SRH 840 headphone is much lower than the Aonic 5, it pushes the noise below the threshold of hearing.

This means that the measurements and specs on the Yulong website are probably referenced to the DA8 II in DAC mode and not taken from the headphone out.

For the HRT HeadStreamer, it's a bit strange that the noise is related to the Windows system volume. Are you sure that Windows / foobar is giving you the correct sample rate / bit depth for the music you're listening to?

My suggestion is to find an amp that offers a very high signal to noise ratio even at very low power. A JDS Atom seems to fit the bill and it's fairly inexpensive. Try hooking it up to the Yulong in DAC mode. Hopefully you'll have a noise free system with your Aonic 5.

HRT HeadStreamer: Are you sure that Windows / foobar is giving you the correct sample rate / bit depth for the music you're listening to?

>>100%. If I watch a youtube video: 48k. If I listen music in foobar 44.1k or 96k depending on the source. For foobar I use Wasapi.

>>Changing the volume in foobar has no impact on the noise. Only the windows volume (I use windows 11).

I think you are right, this is related with the how the Yulong works (not a defect, but maybe a bug). Adding just an amp sounds like an acceptable solution to keep the DAC quality of Yulong. I will look into it.

Any other option than the JDS Atom? Something older that I can hope to find second hand?

Thanks! great input.

Actually this review mentioned the IEM problem (they called it "hiss"): Review

I try to convince myself that the sound quality of the HRT Headstreamer is the same of the Yulong and that I don't need anything else, unfortunatly that is NOT the case. 

I also try to convince myself that the Aonic 5 get me the best sound, but it falls so much short of my Totem Mani 2....