[bmwdad]

I will be getting my zo3 on tuesday aug 19. (traveling)  and post a review.  I am hoping that the zo3 can give a little punch to my Nad Hp 50's, which are great except down low.

 

[caprimulgus]

 
It's basically the same. The improvements are elsewhere.

 
ah cheers. as i said, i'm not too interested in enhancing highs (i'd personally prefer a negative adjustment to highs, or an enhancement of mids, if anything), so if the bass is the same, the ZO3 wouldn't really be an upgrade for me aside for aesthetically (but i'd prefer the smaller form factor on the ZO2.3 anyway).
 
was hoping there would be amping and sound quality improvements in addition to the "full spectrum" (which isn't really "full" without mids!).
 
thanks for the feedback. keen to hear whether others share your conclusion.
 

 
I'd hate it to be the same because I personally prefer the ZO2.1's bass (more punchy/impactful/harder hitting) over ZO2.3 (softer, a bit more loose). Might be a case of some people not able to tell the difference and some might, anyway I have a ZO FS+ incoming so will judge for myself.
 

 
yeah, awaiting your impressions in particular!

 

[RPGWiZaRD]

   
ah cheers. as i said, i'm not too interested in enhancing highs (i'd personally prefer a negative adjustment to highs, or an enhancement of mids, if anything), so if the bass is the same, the ZO3 wouldn't really be an upgrade for me aside for aesthetically (but i'd prefer the smaller form factor on the ZO2.3 anyway).
 
was hoping there would be amping and sound quality improvements in addition to the "full spectrum" (which isn't really "full" without mids!).
 
thanks for the feedback. keen to hear whether others share your conclusion.

You seem to be on the same level as me on the things, I've also suggested the same thing about being able to adjust the highs negatively allowing a more warmer/forward midrange instead. ZO2.3 I found slightly bit V-shape sounding while the ZO2.1 is in terms of timbre possibly slightly the opposite with pretty smooth highs but very fullbodied midrange (lower-mids in particular) why I tend to prefer it over ZO2.3 because the mids sound really romantic, thick without sounding muddy whatsoever on my Q40 (seems like a perfect synergy!). I'm keeping my fingers crossed that the default levels of ZO FS has the highs reasonably laid-back/smooth and not forward since otherwise the highs boost will be kind of pointless if it already to begin with in the standard settings provides a boosted highs sound. It might also try to see if I could get them to configure the SmartVektor curve used for ZO2.1 in ZO FS for me in case it turns out I still like the balancing of ZO2.1 better than ZO FS but that remains to be heard.

Anyway they might bring more configurability in the future like possibly (at least they are interested in it when I've asked about it) custom manageable SmartVektor curves it seems (not for ZO FS) but some future products. To me a "EQ'able" SmartVektor curve would be the final nail in the coffin to make ZO something like a Swiss army knife in portable headphone amp that does it all.

 

[phrosty]

More reviews...
 
Beyerdynamic DT-880 600Ω
 
A while after I first got these cans, I had this crazy idea of feeding them with my ZO 2.3. Well obviously that didn't work, but I eventually daisy-chained the ZO into another amp just to get that sweet bass.
 
I was really happy to see the ZO FS powering these alone and without a sweat. I spent all day with them yesterday. The DT-880 retained their high degree of clarity, and gained a great amount of bass. Unlike the DT-770, who's closed design amplifies the bass and muddies up at too high a contour, I was able to crank the bass up between 24 to 32 without everything else getting swallowed. The FS turned these into bass monsters and sound great!
 
The DT-880 were the first headphones I tried that got a noticeable change from treble SVT. It's still hard to tell with something as chaotic as dubstep, but bring a little trance in and you can readily hear the highs sharpening up. It's an interesting sound, and I understand why they made it subtle -- at mid contour levels it seems to add a little... something, hard to describe.... but at the highest levels, I quickly got fatigued and had to take my headphones off for a little rest.
 
Superlux 668b
 
These cheapie things I bought on a whim when some of you started talking about it seem to just keep surprising me. When plugged into the ZO, the bass becomes very tight and punchy, and super deep. It's startling how phenomenal these cans sound with the ZO -- if you've got them, I urge you to try it.
 
I could also hear the treble SVT pretty well here. It seems to take on a better effect with semi-open cans than closed ones like I had in my previous post. Again, it seems best noticeable with trance. It remained a subtle effect here as well, but was less fatiguing at higher levels than the 880s.
 
Unfortunately my time was cut a little short with these, as I had some technical difficulties mid-day that I'm working to resolve right now. Once I get it fixed, I'll try out some IEMs and post some comparison recordings for you guys who're holding off.
 

  was hoping there would be amping and sound quality improvements in addition to the "full spectrum" (which isn't really "full" without mids!).

 
The bass SVT part of it remains the same -- as far as I can tell, having treble SVT at 0 is identical to the 2.3. But like I said, I'll post some samples for you to compare.
 
But, there are definite amping and quality improvements that make it worth it. It's now a high quality amp.

 

[phrosty]

First sample, some dubstep/breaks - DotEXE's Battle Cry. 30 sec clip of it only -- first number is bass, second is treble. Takes a while to prepare these so maybe one or two a day.
 
https://mega.co.nz/#!9o5W1LiZ!hVhzJDL2Iip34JUYlGgkZSRlkAyn5Drpne5RwWVa5fc

 

[Oregonian]

So first impressions -
 
Packaging is.........well, not really packaging.  The ZO 2.3 came in a pseudo-retail looking package.  This came in a box with black foam hand cut out to fit the amp.  I'm not complaining, just for that price I sort of expected something a little more.
 
Feeding a pair of M-Audio Q40's.
 
Treble - I have it up on 32 and have not noticed any change from 20-32 at all.  None. 
 
Bass - I'm running it at 26 right now coupled with volume at 175 and it sounds lovely. 
 
Overall sound - very good.  Need to spend more time with it this weekend and try it out with my HE-400's, D5000's and D600's and will report more back.
 
Here's how I have it hooked up.  iPod Classic via FiiO LOD to ZO3 mounted on an armband for portability.  Held in place with velcro on the back.  Very sturdy for running, yardwork, etc. 
 
So far I like it.  Not sure if it's better than the Arrow 3G I sold to get this but I'll give it time. 
 

 

[Deviltooth]

If anyone wants to test these with IEMs I'd be happy to read their impressions.

 

[RPGWiZaRD]

  First sample, some dubstep/breaks - DotEXE's Battle Cry. 30 sec clip of it only -- first number is bass, second is treble. Takes a while to prepare these so maybe one or two a day.
 
https://mega.co.nz/#!9o5W1LiZ!hVhzJDL2Iip34JUYlGgkZSRlkAyn5Drpne5RwWVa5fc

 
There's a pretty obvious difference between the treble settings listening with my Q40 + ZO2.1 (although since I've already boosted the bass it gets a bit too bassy ) Interesting thing though is it sounds more like the mids are boosted than highs which to me is very cool (or maybe I should have said the mids gets more boosted than I thought it would be as I expected a thinny sound at the high treble setting which isn't the case here). But that could be a poor translation to how it actually sounds out of the hardware itself I guess possibly. Also the ZO settings are much lower in volume giving not the "most impressive" impressions that it does if you try volume matching.

Based on this examples though it seems like I might very well like it as it seems to have a pretty warm character but I like how punchy and dynamic it starts sounding at the 32-32 setting. The treble boost works interestingly, it's more like a dynamicness boost somehow, giving the bass drums more "punch" compared to just using 32-0, the 32-32 makes the bass pound nicer with much better detail.

It seems to be doing quite the same as when I keep mastering hardstyle tracks, giving a slight highs boost can actually make the kickdrum sound harder since the "punch" part of the hardstyle kick is brought more forward, same thing seems to be applying here. Curious to hear it in action from the actual device though.

TLDR; seems like the treble boost might be a lot more useful/better than I had expected the way it's configured (seems more tastefully/subtle configured for more serious listeners rather than aimed towards the average joe).

EDIT: Holy crap, that DotEXE track is like compressed to unreal levels checking the waveform of the original file, never seen such loud master before and I thought hardstyle tracks were bad in that department. lol

 

[Oregonian]

  So first impressions -
 
Packaging is.........well, not really packaging.  The ZO 2.3 came in a pseudo-retail looking package.  This came in a box with black foam hand cut out to fit the amp.  I'm not complaining, just for that price I sort of expected something a little more.
 
Feeding a pair of M-Audio Q40's.
 
Treble - I have it up on 32 and have not noticed any change from 20-32 at all.  None. 
 
Bass - I'm running it at 26 right now coupled with volume at 175 and it sounds lovely. 
 
Overall sound - very good.  Need to spend more time with it this weekend and try it out with my HE-400's, D5000's and D600's and will report more back.
 
Here's how I have it hooked up.  iPod Classic via FiiO LOD to ZO3 mounted on an armband for portability.  Held in place with velcro on the back.  Very sturdy for running, yardwork, etc. 
 
So far I like it.  Not sure if it's better than the Arrow 3G I sold to get this but I'll give it time. 
 
 

 
Upon further review...............
 
This thing is AWESOME.  The treble still is not very useful and I leave it at 32 all the time but the bass run at 25 and volume around 135-145 (my saying 175 above was a typo!) gives great depth to the music and great punch with my Q40's.  Been doing yardwork for the past four hours with this ZO running off my iPod and it really has made me smile.  I think I do like it more than the Arrow 3G. 
 
Well done Digizoid. 
 
Now about that treble adjustment................

 

[zaim]

I managed to collect mine from my local depot today.
 
Earphones- Sony XBA-H3
Source- Sony Xperia Z2
 
I have to say I wasn't impressed when I opened the fedex bag to find a generic white box, I expected something better if not similar to the ZO2. But I guess it did the job keeping the player and accessories together.
 
Next thing I noticed was my unit appears to have small marks on the rear, minor imperfections which at $250 shouldn't exist in my opinion.
 
Moving on from that I was impressed with how the amp felt in the hand, build quality is pretty good, certainly a upgrade from the Zo2.
 
Treble- I have to say I was looking forward to this part of the test but i've had mixed results, like others have mentioned you can ramp it up to 32 and not really notice a lot of difference. However I have come across a few tracks where you notice a fairly decent increase in high's, Not sure why its like this but yeah. 
 
Bass- I've got this set to max and found it really does make the sub bass (25hz+) sound a lot louder on certain music, Unfortunately I sold my ZO2 6 months ago so I can't compare the difference between the two amps in this area, but from what I can recall the ZO2 on max increased the higher bass frequencies a little too far. This isn't the case with the ZS FS, so in the bass department I'm quite happy. If anything it would be nice if there was a user configurable SVT EQ/Curve. 
 
Issue's- I'm not sure if its a faulty cable that's been provided but I am getting crackle/pop sounds when I have been clicking through the menu's on my phone, it seems to happen if I stop/play the music for a few seconds and say go into another folder or menu. This doesn't happen if I connect my earphones up directly. I'm getting the same with my Tablet, I really hope its not the amp as I'd hate to have to send it back after waiting a month for it to arrive. I'll be giving this ago with another cable tomorrow.

 

[Oregonian]

Are you using a LOD or just a 3.5 feed?

 

[zaim]

Are you using a LOD or just a 3.5 feed?

I'm using 3.5, looks like its not a cable issue as I've just tried a few

 

[MuZo2]

 

[phrosty]

Final review - IEMs.
 
Etymotic ER6i
 
I'm pretty much always at a place where I don't mind wearing full-sized headphones, so I don't use IEMs much anymore. Hence these are a rather old model, but I've got brand-new filters for them and they sound good as ever, so lets go for it. The ER6i have analytical mids and highs, but very anemic bass. Honestly I'm not expecting much here, because even the ZO 2.3 could only bring out a tiny bit of bass on these. They're also very sensitive, and are sure to highlight any flaws.
 
The first thing I notice before I get to playing music is a constant static hiss. The next thing is clicking noises any time you press the button. When an animation occurs, like switching to a different setting, you hear clicking during the whole thing. There also must be some kind of timer running, because there are two distinct clicks about every 3 seconds. Present with or without a source plugged in, and without any USB plugged in, it's definitely coming from the ZO.
 
At higher volume—not unreasonably high, lets say 80—I couldn't make out the noise except in quiet passages.
 
At low volume—what I'd listen to in a quiet area, around 50—the noise was readily present. Noise during menu actions is manageable, but the clicks every few seconds are right on the edge of distraction. Like broccoli in someone's teeth you won't notice it immediately but once you do, it's all you can pay attention to. By comparison, my other go-to portable amp is virtually noise-free with these IEMs at all volume levels.
 
Luckily, the noise is all post-amping and a 75Ω resistor adapter I had laying around completely eliminated it. I kept it off for the rest of the test just to ensure I was hearing the ZO properly, but I could not discern any differences in frequency response with or without it. The noise is less loud than the 2.3, but the pattern of that tick every few seconds makes it in my mind a step back.
 
The second thing I noticed is that, wow, this is the first amp I've been able to easily fine-tune a correct volume for IEMs with. I've got 50 distinct levels to use between 40-90. Bravo for that.
 
Regarding bass SVT, these IEMs have a very sharp rolloff starting around 70-80Hz. As expected, the ZO did as well as it could producing a bit more bass but overall for most songs it just made the mix a bit warmer.
 
Treble SVT, on the other hand, really came alive! No longer a subtle change, I could readily hear the music getting clean, sparkly highs and more textured mids as I swept from 0-32. I didn't find it fatiguing at all here and really enjoy it around 16-24. Very impressive.
 
More Samples
 
First number is bass, second number is treble.
 
https://mega.co.nz/#!8owzWYgb!EVhMhp1cWsa76gkXsGGQEbcuGJwR_BiQ80QlE4O8j3g
 
Now including:

1. (dubstep/breaks) DotEXE's Battle Cry
2. (film score) Abel Korzeniowski's Copernicus' Star
3. (pop) Misterwives' Reflections
4. (synth-pop?) Yip Deceiver's Get Strict

 

[MizMoxie]

  I managed to collect mine from my local depot today.
 
Earphones- Sony XBA-H3
Source- Sony Xperia Z2
 
I have to say I wasn't impressed when I opened the fedex bag to find a generic white box, I expected something better if not similar to the ZO2. But I guess it did the job keeping the player and accessories together.
 
Next thing I noticed was my unit appears to have small marks on the rear, minor imperfections which at $250 shouldn't exist in my opinion.
 
Moving on from that I was impressed with how the amp felt in the hand, build quality is pretty good, certainly a upgrade from the Zo2.
 
Treble- I have to say I was looking forward to this part of the test but i've had mixed results, like others have mentioned you can ramp it up to 32 and not really notice a lot of difference. However I have come across a few tracks where you notice a fairly decent increase in high's, Not sure why its like this but yeah. 
 
Bass- I've got this set to max and found it really does make the sub bass (25hz+) sound a lot louder on certain music, Unfortunately I sold my ZO2 6 months ago so I can't compare the difference between the two amps in this area, but from what I can recall the ZO2 on max increased the higher bass frequencies a little too far. This isn't the case with the ZS FS, so in the bass department I'm quite happy. If anything it would be nice if there was a user configurable SVT EQ/Curve. 
 
Issue's- I'm not sure if its a faulty cable that's been provided but I am getting crackle/pop sounds when I have been clicking through the menu's on my phone, it seems to happen if I stop/play the music for a few seconds and say go into another folder or menu. This doesn't happen if I connect my earphones up directly. I'm getting the same with my Tablet, I really hope its not the amp as I'd hate to have to send it back after waiting a month for it to arrive. I'll be giving this ago with another cable tomorrow.

 
Regarding the crackle/popping sounds — Since it only seems to occur while you are actively using your phone/tablet, then chances are they're being generated by your audio sources, and not the cable or ZO. To be sure, could you please answer the following questions: 
 

• What volume settings are you using on both your audio source and ZO?
• What app(s) are you using to playback music and what other apps do you have running in the background while listening? Are you using the phone's built-in NFC feature (or any other wireless features) to communicate to other devices or access cloud-based music libraries? 
• Have you tried putting your devices into airplane mode?