Hey thanks for your input! The changes they claim are all true, but I'm sure each of them only have a very very small effect on the sound, and that the rest of the dap implementation has more of an effect on the sound, that's why I'm more interested in sound impressions. There is a pic of F880 and ZX1 where you can see the changes clearly:
![](https://www.head-fi.org/attachments/1427545/)
Thicker wires on ZX1, which would mean slightly lower internal impedance, would technically extend bass and treble response (very slightly)
Os-con capacitors (essentially means aluminum polymer capacitors) on ZX1 compared to the completely ordinary ceramics used in the F880, os-cons should increases bass and power due to larger capacitance (ZX1-15mW, F880-10mW)
Larger coil resistors on ZX1 output, which reduces distortion.
A10 would most likely have wires thicker than F880, but not as thick as ZX1
A10 has poscap capacitors (essentially means tantalum capacitors), which are much better than the ordinary ceramics in the F880, not quite as good as os-con in ZX1, but poscap is closer to os-con than to ordinary ceramics.
A10 is touted as using high purity solder, while the ZX1 and F880 aren't, makes it more likely the A10 is using some variation of the 99% tin solder that the ZX2 uses.
From a technical point of view all these will change the sound to some very small degree, as all the changes are messing with impedance, resistance, distortion, capacitance. But I agree with you that these changes will only be reflected in the sound to a very very small degree. The actual circuitry implementation and software implementation will affect the sound more than these little changes. which is why I am more interested in sound impressions, because it is the dap as a whole unit that is producing the sound, not these little changes individually.
Which brings me to your impressions, you say the F880 has a 'tac' noise, are you talking about hiss or hum? sounds damn annoying, and did the A10 have anything like this? Hmm, your making it harder to choose between F880 and A10!