200+ hours passed and I can say that this amp is smooth, dynamic and super detailed! Loving its addictive yet not distracting sound nature.
So what I would like to see in future revision:
- Inclusion of ODAC; Perhaps make it to match ipod touch length and therefore give yourself more room to add other stuff like a DAC. DAC and 627x complement each other greatly. I find ODAC very dynamic and adding it to a dynamic amp really leaves no room for improvement in terms of sound. With a longer case it should be possible to fit the ODAC in without a problem.
- True PSU usage: As much as I am a fan of clean power but completely relying on the internal battery will reduce the battery life. It would be great to see in future revision to only run on the PSU when it is connected instead of relying on battery and charging it contionously (something that O2 does.
- RMF coating: I've noticed that when the when I have the 627x plugged in it will produce noise if I touch the casing.
- Further reduction of hiss: I consider this as a bonus as the unit as is is quiet silent but there is an audible hiss that increases with volume increase.
Beside this three there is nothing significantly wrong with this amp and I believe with the above modification this will become truly the best single ended amp in the market. And no Lisa III is not portable at all.
Side note: I have noticed that 627x relaxes the bass and sub-bass which can be an issue for some. For example when I used the AK120 as a source feeding the 627x I lost a nice bit of bass quantity on my CK100PRO but as soon as I plugged in the CK100PRO to the AK120 it became obvious that the 627x was reducing the bass quantity.
In general 627x gives more dynamic to the sound, tops becomes smoother and midrange becomes the key player where as the low end are present but play secondary role compared to the mid-range.
Is this a bad thing? Well for those who listen on short interval it can be as those folks like to get a quick high on music but for those who like to listen for long hours the change makes for a much easier listening session with what is safe to say a zero sound fatigue from 627x behalf.
Edited by audionewbi - 7/6/13 at 9:34pm