The amp arrived today.
The finish looks nice for the price paid, I'm quite pleased with how the amp looks like, it does feel quite good for its price. Since I got the AC adapter version, the power adapter already came with a chinese power plug->europe converter so that's nice, I was worried I might have to go buy an converter but it came with one. To give some criticism the power adapter itself is probably the cheapest looking adapter I've seen in quite a while and it's also very light but yea it's quite expected from a DIYer. I had personally preferred having the outputs at the front.
Early impressions is that it's a fairly balanced sounding amp, nothing sticks out too much. For me it sounds best with both SRS and QEQ disabled, well SRS on with the SRS volume knob turned all the way down sounds also quite good, but it functions mostly as a gain boost. As I turn up the volume for SRS there's more SRS sound effect enabled and bass also disappears the higher you go, it's almost totally gone at SRS volume at full and sounds like an echoing chamber, not very useful at all. The QEQ is a V-shape EQ setting which doesn't appeal to me or Q40 anyway but with dark headphones it may work but the mids sounded quite muddy on Q40 with it. Right know I wouldn't say it's either a good or bad amp, it does sound better than a FiiO E5 I'd say but it doesn't sound as good as digiZoid ZO2.1 with M-Audio Q40 headphones for sure but that amp is also like 3x expensier. It's been quite a while since I've had Gary's PA2V2 but I think this one might be somewhat comparable, but I think Gary's might have slightly stronger output (well probably not if SRS is enabled). I'd say compared to the digiZoid amps this amp has slightly more highs presence, particularly around the 8kHz area and up, the digiZoid amps are slightly smoothening out the highs though compared to ampless listen and this at least keeps it comparable to ampless listen if not ever so tiny bit added sparkle. The bass is quite nicely presented, decent punch to it and well controlled for the price, beats easily the FiiO E5 amp with EQ set to bass boost enabled and it might even have somewhat comparable quantity too, probably tiny bit less but E5's bass boost is very tiny to begin with but the bass bleeds into the mids on E5 which it doesn't at all with the SRS Listen amp, in fact it improves the bass bleed
conciderably and provides better bass control with the XB500.
I tested with my most efficient headphones XB500 and it's dead silent with SRS disabled and only almost in-audible hissing heard when SRS switch is flicked on, so that's nice, even less hissing than with the latest ZO2.3 amp but with SRS disabled it didn't give as much output volume as digiZoid ZO2.1 does but with SRS enabled it definitely goes at least equally loud, it's probably slightly more comparable (SRS disabled) with digiZoid ZO2.3 volume wise which has a lower gain than ZO2.1.
EDIT: Liking how the mids sounds like on XB500 with this amp, the clearest vocals I've heard with this headphone so far. Seems like it has better synergy with XB500 than Q40, the Q40 loves the ZO2.1 then again (much more than ZO2.3 for some reason too).
EDIT2: I'm beginning to put this amp towards the more bright side as even with XB500 the highs can get slightly piercing in some songs at a volume setting where I find mids and bass to sound appropriate, I have to adjust the volume against the piercing highs to get comfortable with it but I believe this might be due to being used with digiZoid amp's smooth highs so I can't accurately describe whether this can be concidered neutral or emphasized highs, but at least I can say it's brighter than that of the digiZoid amps.
EDIT3: After comparing some more with SRS on/off I can also say with SRS on (and SRS volume knob minimized) the highs are a bit less bright but the clarity&transparency seems slightly worse too but the mids at the same time gets a little bit more forward, this is nice as it gives an alternative if disabled doesn't work for you.
EDIT4: I'm really starting to believe this amp was made for XB500, it pairs the best with this headphone. I did some comparision ampless and amped on the song B.o.B. ft. Taylor Swift - Both of Us as I believe this is more up XB500's alley and it just sounds a lot better with this amp than ampless, the bass is tightened up and gives a slightly better punch, the whole midrange comes noticably forward and doesn't sound hidden behind the bass like it kinda does ampless, all in all everything sounds quite nicely balanced despite we're talking about a bass monster headphone here!
I'm starting to like it more and more with Q40 too but now I'm gonna use it for a while to get more familiar with it and let it burn in.
There's also a link to a 
