My previous post on not being able to access the android volume using USB Audio Pro has since been resolved (my bad) and I can confirm the usb2 and android diy dacs perform beautifully on a windows notebook, android tablet (ifive 3g) and phone (Jaiyu g4t) with no additional amplification for both the Sennheiser CX150 (16ohm) and AKG451 (32ohm). However, there is a significant (30%?) faster drain in the battery which is not unexpected.
Please can someone confirm if I will get sufficient volume using the following headphones without the need for a headphone amp (VSonic vsd3s (40ohm) and havi b3 pro (30 ohm)) .
Presumably the lower the impedance the greater the volume (and distortion ?).
If I do need amplification on android what products from HiFIMe would I need to buy eg. OTG USB cable, U2 USB DAC and ????