the capacitors around the audio output stage are already very good caps : 10uF Rubycon YXF low ESR for the opa1612 330uF Rubycon ZLH very low ESR and 10uF YXF for the 2 BUF634 All that are among the best available components So I guess the V5i issue is not the capacitors

  the click comes from a safety relay with time delay at the output stage

it's used on the probably best headphone amp actually (Neurochrome hp-1)

interesting the measures confirm that opa1612 is the best opamp for audio portable gear actually on the market maybe the audible difference is because the impedance output is different with the V5i, so the frequency curve would be also slightly different frequency curve is the main reason for...

op-amp rolling is not so good Each opamp has its own characteristics and it is better to make new measurements ( noise, THD... ) after an opamp rolling I love the sound of the xduoo with the stock opamp on my Philips X2, and if you want to modify the sound to your taste, i think it' s more...

this is probably because it has a very low output impedance ( about 0.4ohm) If you compare with another amp with a higher impedance, on a headphone with a rather low impedance and/or mechanically low-damped membrane, there will be a slight bump in the low end (see the different measurements on...

Hi i confirm , K75-10 are very nice caps , better than K40 IMO i've not tried to bypass with teflon FT