Digizoid Zo2.3 – Portable Headphone Amplifier Review
Portable amps hey, something that most people think of when they are first building a portable rig and something I get asked about quite a lot. However what you want yours to do to your it may be different from one person to the next and at the end of the day we want it to fulfill are craze for what we think is the best sound. Well this amp has another name that it goes by, the personal subwoofer and that to me is it clearly out lining its targets and that would be you bassheads out there. However I want to take it like I would any other amp and run it through its paces to see what it really is all about as it looks to boast a lot more than just its ability to be a subwoofer.
I would also like to thank Top Dog Headphones in the UK for sending me this to review and they are thankfully the only UK distributor for it and sell it for a measly £79.
In the box we are first greeted by some instructions. We then delve into the actual box and that’s when we meet the Zo at long last and with it is of course its USB charger and also a little 3.5mm to 3.5mm interconnect so you can get going right away. We do not get a plethora of accessories such as we get with the Fiio E17 for example but this is an amp and we get what we need which is not something worth complaining about.
Design and Features:
The design of this amp is awesome. At first it may look understated with its soft black finish and it simply having ZO2 written on it.... and then we turn it one and you get the light that is the soul of the Zo. It is something that defines the Zo as something different and I love it for that and also for the fact how they have braved to use this little light as the way that you navigate through the Zo. However as I wrote this I did not help but think this could cause some problems for someone who is colour blind possibly as I know a few mates who are and this would trouble.
As for features it has loads while maintaining a subtle exterior. I mean looking at it you may think this has what looks like a volume control, a 3.5mm input and output and a mini USB input, what could you do with that? A hell of a lot actually as it happens. Now as you take in all this does do not think this will be impossible to use as although at first using it takes something thinking it becomes habit and ease rather quickly.
So first of all we turn it on by clicking the wheel and we get a orange light on the Zo. We are now on the sound signature tuning mode and this is where we can adjust the bass of your earphones and it is a handy feature as you have whopping 32 different settings to try but more on that later.
Then if we click the wheel again we get a pink light the first time we use it. Here we have connection configuration mode and this will offer two gain modes with different suitability’s toward how you connect the amp to source. The pink mode that we start on is high gain and specifically for if we are using a mini to mini interconnect so one with a 3.5mm jack each side. What this means is that the volume on the Zo is fixed and we will simply use the source to control volume and leave the amp as it is which is pretty nifty I think. Then if we want to use a line out dock with your source and the Zo (like I do) we take it too the low gain setting and here we can use the Zo to control the volume as your source gets that function removed. To get to hear we rotate the wheel down and go from pink to purple and that is the highest volume in low gain mode. We then can keep turning up and down to adjust volume from purple being the highest and dark blue the lowest. To get back to the high gain mode then hold the wheel up for 8 seconds. May sound like a lot here but it is no big deal at all and you get used to it in a matter of days.
Lowest bass setting = Green Highest bass setting = red
Low Gain mode = Light Blue to Purple High Gain mode = Pink
Apart from that we also have USB charging and it is a simple case of plug in and go with the included cable which as one end being full sized USB and goes into your computers USB port and the other end is mini USB and goes straight to the ZO.
This is where I look at how it will suit different players as I know that people want to use their smart phones as a source and then an amp with that. However many amps I have tried suffer from EFI or interference for radio transmissions that your phone make which can make unbearable noises and even cut out amps. Well this did not suffer that bad really and I actually think this pairs quite nice with my iPhone as its warmth balances the iPhones brightness. We get the odd fuzz here and now that I would like gone and I have seen amps get rid of it completely but it is far from enough to stop you enjoying it and I mean far from enough.
Size and Portability:
As this is at the end of the day a portable amp, portability is of course one of the most important factors and this has absolutely nailed it. When I got my hippo cricri I could not believe how small it was and I actually struggled to believe that the Zo could be as small as it and to say that the Zo is the same width, has less depth and the slightest bit more height (it is like the iPhone 5 to the iPhone 4) is really impressive. It ticks all the boxes in the size department for sure and its exact measurements are:
Length – 7cm
Width – 3.8cm
Depth – 1cm
It also ticks my other main portability concern and that is weight. It weighs in at a tiny 26.6 grams being made of just plastic and I do not really feel like it adds any real weight to my super small rig that included a tiny third generation iPod Nano.
It is also said to boast a whopping 17 hour battery life and I can agree with that and this thing outlived my hippo cricri on the go using them each an hour at a time so can not complain with any of these areas and this aces portability in a headphone amplifier.
So I thought this thing is made for portable use but why not test it out with some extremely hard to driver headphones too see how it did and I am going to be blunt an honest it cannot manage. I used my Sennheiser HD580 to test this section with their huge 300 ohms impedance. This is the worst I have ever heard my HD580s sound and it did not matter what gain setting I had them on, everything just sounded bad. These are made for use with IEMs that are fairly sensitive and have low impedance. Don’t expect this to driver your new Hifiman HE500 for example.
Sometimes and amp are so powerful that with anything slightly sensitive you will get an extremely noticeable underlying hiss. Of course if you plan to use these with your sensitive IEMs or closed headphones with your portable amp you do not want no hiss because that would just put a spoil on your listening experience right. Well I stuck the most sensitive IEMs in my possession (Shure SE535) into the amp and checked out how they coped and I really did not hear that much or any hiss. However the amp plays them at the quietest it can go fairly loud so that is a big down side, you can not get near mute like I would like. Hiss is not a problem at the end of the day and this is just now powerful enough an amp for hiss and any one will back me up in saying that the SE535 is nearly the most sensitive IEMs you will find.
The build quality is also something a portable amp needs and lately I have been very impressed with what I have been seeing with a lot of metal amps and the Fiio E17 which is just done so magnificently. Now I will first say that the Zo is all plastic and secondly that it does not super plush. The plush thing stems from the seam going all the way round the outside of the amp and where there is the reset button and the USB input I feel like it would not take much to prize the whole map open. The other worry is that the volume wheel feels a bit loose in side the amp and also that it is made of a real cheap plastic. Now we can move onto the positives. The two female jacks look really secure and like they will not cause any problems and the lack of a lot of buttons and physical features is another huge plus. The last good thing and the only thing that stopped me ripping the construction to shreds is that the actual plastic of the housing is actually very strong and nice feeling.
With an amplifier to hit perfection I guess we will ask for perfect transparency with no coloration so that it can reveal completely the source which also be completely transparent but obviously that is hard to come by and also very expensive to get close. Anyhow I currently have no extremely transparent sources that have a perfect black background (although I have a self proclaimed one on the way, the Terra Player) but I do have some amp that are not coloured and really clear and too me that is the aim of the amp, transparency and of course the ability to synergize with my headphones (but more on that later). Now of course not every one strives for that transparency like me but if you do you may well look away now, as this is not the amp for you.
The signature of this amp is a bass creature and even when you have it on a light amber light that is pretty much neutral as far as this amp is concerned. I will quickly go to say that we can go green which makes it sound like the bass has disappeared and by going al the way up to red the bass is just crazy big with loads of thump and even more rumble, truly outstanding that so much is present and so different to what a silly EQ boost can do off of your phone. Anyway back to the sound on what I think are the most medium setting and what I shall be using for the rest of this review. SO yes, it is a bass monster and when I say bass I am talking the low frequencies, the ones that give you that oh so satisfying rumble that we like and it can give it to even the most bass light IEMs or headphones. It is also overly warm and coloured and far from transparent, in all honesty the sound is thick and muddy and while we do have more bass it is not as quick as before and the mids sound smeared by it ever so slightly. The treble is something else and it actually takes a step down with a lack of sparkle present than before and already dark headphones suffer. As for soundstage that is really nice and the sound is more open and spread out. The warmth of the amp however does make everything sound more cohesive and full and nothing really feels lacking on the amp, it is like snuggling into bed on a cold day with a hot water bottle and overly fun and enjoyable experience capable of putting a smile on any ones face.
So not the amp is not the technically best amp in the world or even its price range and the price range below but I think it could well be the most fun amp ever made and certainly the bassist because on that red contour my mind is blown, I just can think what a pairing of this and the Hippo VB would be like.
Now to me synergy is the most important thing with an amplifier because even if it is the most transparent amp in the world it just may not suit your favourite headphone. Now to do this I have paired this amp with an IEM from each overall signature.
First of all I will start with something that is mid centric and this is the Shure SE535. A quick overview of these headphones would be rolled of treble, prominent mids and bass that lacks impact, texture and to my ears, extension. I also think the lack of overall dynamics on each end makes it sometimes feel empty and shallow. Well that is now gone along with other problems. However it does now sound like a completely different IEM. The bass has caught up with the mids making them the perfect counters and partners in crime. The bass now has impact and texture as well as rumble and extension and instead of this causing the mids to go sour, the forward mids of the SE535 now sit in line with the bass but still sound as lush and as detailed before, so now we have gorgeous mids and bass. However the treble has left the show almost completely and the sound is now a tad dark and lacks overall zing. However although we do lose a bit of the clarity and the treble from the Shures, this now found bass turn these into something else, is it better I do not know as we do lose the prominence of the trademark SE535 mids but we do gain something else. I actually found the two to have a nice pairing and synergy and these can go well with a mid centric headphone, I reckon these could also pair well with the HIFIman RE-262 that I have tried but not with this amp.
The next pairing I will comment on is its effect on a neutral IEM and this was me using the amp with the Heir 4.Ai. This is currently my favourite IEM and I currently use this in my portable rig with my hippo cricri and that is a neutral, transparent and refined amp and synergizes great with the Heir. Now with this we do lose a lot of the magic that the 4.Ai boasts and that is its neutrality because we now have a easily visible lean towards the low frequencies, the transparency and the detail as they are generally more smeared and finally the weight of the timbre which was done just great before now feels a bit heavy. However we do have positives as this now ups the versatility of the IEM and it now will suit pop, dubstep, hip hop and other bass friendly genres very well now and there is still now denying that it is a great sounding IEM and although not quite as detailed as it is with out the amp it is still one marvelously detailed IEM. So although the synergy is not the best here, by owning this amp we can now turn the 4.Ai into a completely new earphone with a new signature when we want too which is rather handy at just £80.
Now what does this do to a bass light IEM (or something people will classify as a bass light IEM) or an analytical IEM depending on what you want to call it. This pairing had me call out the help of my beloved Fischer Audio DBA-02. Now these have very little mid-bass which is tight and punchy and there is no rumble. Well now these have a rather balanced signature and perhaps tilting to bassy depending on the contour that you use. However everything is really clear and still detailed with the slightest of masking. The highs are no longer piercing or close to or ever fatiguing and rather subtle. What I will say is that I prefer how they normally sound but what we now have is something in this price range that will destroy the Vsonic GR07 at its own gain as they are now are rather similar signature and this strangely goes well with analytical IEMs but only if you don’t like them as analytical. What I am starting to find is they take IEMs with little bass but great detail and just complete the sound with some bass which is just great as you have to sacrifice the slightest of amounts of detail but it is still a lot more detailed that any bass heavy IEM you will find in any price range.
Lastly I will pair it with a bass heavy IEM. I will be honest and say that I hate bass heavy earphones/headphones but I still recognize quality in a bass heavy IEM and therefore will still recommend the likes of the Hippo VB for someone whose priority is bass. For this paring I will pair the amp with my last remaining true bass monster and that is the Final Audio Design Adagio III. Obviously the bass is already the focus on these and now it is just taken into overdrive. But this is at the cost even more so of other frequencies. The BASS experience is however taken to un real heights.
I would be lying if I was to recommend this to anyone as a generally great sounding amp because at the end of the day the only real improvements in the sound that I am hearing is a huge one in the bass and a slight one in the soundstage size and that does not come with out its negatives. However I have never had so much fun listening to headphones and some of my more bassy music and it really does change your IEMs into something else. I also really like the design that is super portable and I like the light thing now I have got used to it but bright sunlight does make telling colours apart a bit hard (never happens in the UK). So will I recommend it? 100% YES but on some conditions. If you have a new headphone or IEM that is not hard to driver and you find that it is lacking bass. The other condition is that you have just put up a search for a new headphone that has a bass focus, don’t buy a new headphone just get the Zo it will take care of all of your worries. This will always be a valid part of my collection and will take care of any bass cravings that I have from this day on and maybe even become part of a portable rig when I find something that really synergizes with it well but for now, it will not be taking the place of my cricri on the go.
This amp was once limited to being purchased in the USA but now thanks to Top Dog Headphones this can now be had on the UK and EU which is just great and for a small price of just £79 I don’t see why you wouldn’t go for this for you bass needs.
Where to purchase:
Edited by Swimsonny - 10/2/12 at 9:59am