What bugs me with this noise and hiss from the GO is, that it is dependable of which GO you are using. There are far more complaints with the GO 450 and the GO 720 than with the GO 1000.
LH provided measurements against other competing DACs and stated, that theirs is supperior regarding noise floor. Larry used a "real world" 300 Ohm load. But what is a "real world" load compared to the headphones a normal consumer would use? Regarding the small size of the GO and how it was advertised as being comaptible with iOS + CCK and Android via OTG the GO should be a portable DAC and used preferably with portable Cans / iems / ciems.
Then there was the demand for more power to drive larger cans. But still, it is a portable DAC. I can't belive, that the noise floor is higher with "dirty" usb power provided by the pc/mac/laptop, because other DACs are noise free.
And the 3D Noisifier (I call it Noisifier because of the noise :P) should not make a hissy background. I am happy with my GO 1000, as I don't have sensible headphones, but I can understand the frustration of those, who have GO 450 / 720.
They better make the Pulse hiss/noise free, as this is their midfield DAC. And the firmware should be tested thoroughly regarding the volume jumping to max sound with windows OS. Their volume knob is a digital attenuator and works like the buttons on the GO if I remember correctly. Don't want to fry my headphones, because the volume jumps to 100% (7 Vrms) by touching the volume knob...