hello everyone this is Amir from audio science review today i have a review for you of this
uh audioquest uh dragonfly uh cobalt i guess cobalt blue
this comes in three different versions uh standard one which i think is gray then or black i forget
then there's a red one and then this is the cobalt one and the price incrementally goes up
as you get to this one this is uh 300 for this uh little thing so uh quite expensive it doesn't
look or feel any different than the cheaper ones maybe it feels a little bit more uh glossy but
at any rate it's not something you're gonna look at every day on this thing so for 300 it
better be a darn good dongle um because you can get really nice ones now for 75 to 100
if you're not familiar with this category of device on one side there's a usb connection
and on the other side there's a headphone jack internally there's a dac in there digital to
analog converter and a headphone amplifier two combined are designed to produce better
performance than you can get out of your headphone jack out of your laptop
or if you have a phone that still has a headphone jack or if it doesn't then this is your
only solution something like this is the only solution to get audio out so compared to the
analog output of your desktop we expect these things to have a lot more output
as far as just sheer power of driving headphones otherwise there's no point in having these
whether they provide additional fidelity that's a secondary thing to
have an adequate power and we'll be measuring that on this thing so this is what it looks like
let's get into the review that i post last night um click in my window here
so i do this test in two phases in that at first i treat all of these as if they're just a standalone
deck meaning i don't try to load the output with a headphone style load so it's the least stressful
situation which is what a dac would see when he's driving a preamplifier as opposed to a headphone
and for that i try to adjust the output to 2 volts if i can and see what the performance is so again
it's the best case performance with autoquest cobalt when i ran my dashboard test i the signal
is always 0dbfs which means it's at maximum digital value at peak to peak at the sine wave
when i did that performance was horrendous uh this sign add which indicates noise and distortion
just sank all the way down to 25 or 30. these distortion bars were way to heck up here
and a clear sign that the device wasn't designed to be driven at full amplitude a lot of music
these days is mixed near zero because of these loudness wars so you don't want it uh dac to uh
clip or overload in in in that case excuse me um so i knocked it down one db and that was enough
to get rid of the severe clipping and uh that gave me the two volt nominal which is what a
dag should produce uh and uh performance still pretty dismal uh cyanide again it
says is a measure of all these harmonics added together and the noise floor of the dag combined
and uh we're getting somewhere between 74 and 78 depending on what channel you look at you average
them up you get about i don't know 75 or so 76 and that places the uh um audioquest cobalt um
second worst donkel i've ever tested there's i don't know 25 30 of them in here if not more and
anything bucket red means it's just incompetent essentially at any price much less of 300
ideally you get a device that's in the green and blue is where you want it to be
not weigh the heck down here so as a pure dac this is quite disappointing
um what's interesting is that this uses a pretty competent uh digital to analog converter from ess
that in desktop situation it can actually be way above even these lines over here so
quite surprising it took a really good engine and then screwed up its output to to be this bad
now sometimes the performance is better at lower voltages or lower output levels so let's test for
that and uh as you can see performance just keeps getting worse the more you ask this device to
produce output usually the curve sort of starts low because of the noise level that's dominant
and then it goes up and then it comes back down not here basically
the more output you have the worse the up the performance gets and distortion
increases and then it hits a point where it just clips and performs drops like a rock and
that's all there is um as a sign that there's a good engine in there of that dac is that when
we just measure noise not distortion just measure noise is extremely good it's not the best but it's
way up there this is producing basically 20 bits of dynamic range so very quiet internals in there
it's really the distortion that's the problems all these tile spikes in here the noise floors
is pretty good going back to distortion uh people complain often that you know you're just running
one sine wave that's music not one sine wave so i have a test where i run 32 sine waves at all
different frequencies from 20 hertz all the way up to 20 kilohertz and an ideal output on this would
be that the bottoms will be way down here and there won't be any of this busyness or grass as we
call it here we're getting really bad output but the distortions are generated are covering all the
way up to -80 db if we divide that by six we get about 13 bits of distortion free range so if you
express this clean area you only have 13 bits so i don't know 40 years after cd format was started at
16 bits this device can produce 16 bits i think you know anything about 13 bits it's just pure
distortion and and junk i don't know who can argue that this is euphonic or sounds good it's just
garbage that's just gonna hide detail in your music excuse me um i notice in the description
they talked about it has a slow filter and so i figured i go ahead and measure the filter response
and the way i do that is that i feed this the white noise and white nose has all frequencies
in it so this will go on infinity every dac needs a filter and this one has a filter but this filter
is very slow an ideal filter for this sample rate would truncate everything at this blue line
that doesn't alway most of the time that doesn't happen most stacks have
what i call lazy roll out but the laziness is not as lazy as this and also they don't uh
bring down the levels of audio audible band too much there's about five or six db droop
over here at 20 kilohertz fortunately most of us don't hear that but if we did hear it
you know you're basically losing some of your highs in there so not good um this is done
because of this notion that normal dac filters are sharper and are flat in the audible band
ring meaning that they oscillate and then they have a spike and then they oscillate that only
happens with artificial test signal and impulse doesn't happen with music but what the heck we'll
go ahead and run a square wave test and indeed we see that there is uh only pulse ringing and so
the signal comes and we see the ringing after it we don't see any ringing before it so it's doing
what he says it's doing even though audibility of this thing is quite suspect this kind of filter
but uh despite the fact that i'm running this at -2 db uh full scales not even one we see the
tops of these things i don't know if you can see they're flat they should be little points like
this not flattened when they're flattened meaning that the dac is internally digitally clipping
and when it clips it generates distortion so this is not good it's an overflow digital systems
cannot handle overflow uh they they're great till you get to zero and then they can't go above zero
so there's a signal processing error here uh it's rather common uh it happens
so uh but still not forgivable you know we don't want clipping in the name of the code a dac
filter that we can't even quantify what it does for us it uh gets rid of some of our frequency
response up here and then it gets and it then clips in in time domain so not good
but this shackle of high personality continues when i test for accuracy of of the output
in a linearity test is exceptionally good it's almost textbook perfect all the way up to 20
bits again 120 minus 120 db so there's great performance there it's great performance in a
jitter test yes there's some unwanted spikes here you should only see this one spike in the middle
that's our test signal everything else should be you know it shouldn't be there we've seen these
little ticks in here and that's common especially in this class device but the levels are all below
minus 130 db and lower so absolutely inaudible um on this thing so definitely not a concern so
performance goes from being you know really terrible to really good now a lot of these
things where i've shown you it's not clear that you know average person even hears this high uh
distortion uh here distortions you need training and and right content to hear it and
uh at this level i think most audiophiles wouldn't hear these artifacts even though you know ideally
you want to get a piece of hardware that doesn't have those problems so but what you do here is
power as i mentioned at the start of this review in that if you run out of power either the thing
doesn't get loud enough to drive your headphone or it will get severely distorted in this case
when i'm running a 300 ohm load which simulates something like a sennheiser hd 650 or hd6xx series
headphones are quite popular for these we measure we keep increasing the input relative
and measure what comes out as far as output watts in here and how much distortion we get
once again we see this is a very high distortion device in that you know before you even get to
0.1 milliwatts this is 0.1 we're already having distortion taken over and increasing with level
and uh then it gets to a point of about 12 milliwatt and then it jumps up uh unclips
so you know this is your usable ranges in here so if i take that 12 milliwatt and i plot it with all
the other dongles like this that i've tested it lands in here uh your phone it like is way down
here like this htc i think it's the htc phone i don't know if i can see my oh here we go by
i think this is my samsung phone i'm not sure but if you have a regular phone with without a
dongle uh other than some lg phones uh you're way down here so there's plenty more power
than your uh typical uh uh either phone or if you buy little dongles like the apple dongle here's
three and a half milliwatts this thing puts out 12 milliwatts so it's four times more powerful
than the apple dongle which is actually a good dongle on the google and others you could try to
look at the review online so this is actually not bad uh i'd like to see 14 15 16 which is what this
is or in case of higher end ones that have balance outputs like this uh Hidisz s9
in here you can see that it puts out as much as 52 milliwatts which is more than four times the power
so if you have power hungry high impedance headphones you may have trouble with this
we then go to the other extreme because headphones come in all kinds of impedances um that was a test
of a high impedance we want to test low impedance because low impedance stresses current delivery
and a headphone app may be good at voltage and not current or vice versa ideally
it would be good at both so here we see a similar picture where distortion rises early again
and this time though we don't have a lot of power it's 26 milliwatts and if we plot that against all
the other dongles and the phones that i've tested night lands way down here um it should really be
in this category uh over here so this tells me that if you have a high impedance headphone
this dongle probably do okay but if you have a low impedance headphone that lands in this
25 30 ohm range you're not gonna have a lot of power and depending on the efficiency of that
headphone you may have clipping issues or volume issues indeed that's what happened so i always
test with two headphones one at high impedance one at low impedance for that same reason
with sennheiser hd 650 i thought this sounded excellent um plenty of volume plenty of punch
plenty of dynamics detail what distortion was there i couldn't hear it by just listening with
just one sample maybe if i did an a b test between this and another lower distortion
one i could hear a difference but you know for practice as a matter of practice uh it's uh it's
fine uh it's with the high impedance then a second test i do is that i have this ether cx from drop
it's only 25 ohm impedance i tested with that and at very low volume it sounded fine but
the moment i got to medium volume it was already distorted and by the time i got it to max volume
it was severely distorted not a subtle thing maybe not just a little bit bright or anything it was
just completely gone it was basically operating in the clipping region over here uh on this thing
where distortion just goes through the roof it's almost as strong as the signal itself and there's
no mistaking there you you know if you listen to any headphone in this range you're already
in trouble down here yeah this this may be hard to hear but clearly the you know i needed more
power than 26 milliwatts to drive this excuse me um ether cx headphone and that's unfortunate
and whereas if i test with the exact same two headphones ether cx with any of the ones in here
sound is beautiful um you can get the recently reviewed thx onyx one or uh e1da or tempo tech
there's just a ton of choices in here and they're all much cheaper than this and they just have
tremendous performance so what's going on in here basically looks like there's some subsystem is
good in here but basically the headphone amplifier is junk um it doesn't have enough power uh
and it generates a lot of distortion and audioquest is getting unlucky in some
extent so they're sitting on their laurels with this design they're one of the early pioneers
in this area made this category quite popular but some eight or ten years gone by and the race has
moved on and people are now producing these little dongles like this that by the way um come with us
pcs you just have a little cable connected to your phone connecting this to your phone
is pretty onerous because you need a big adapter that then dangles from your phone and having more
weight is not a good thing and even if you plug this into a laptop if you walk away with your
headphone you can break the expensive usb jack in your uh laptop these new ones where they have
you know either a small cable attached or or at least usb-c are much nicer and some of them like
this one actually have volume up and down which is very very good rather than trying to reach into
the device reach into the phone and try to change the volume on this thing so where does it net out
terrible i mean they could have measured all these things found these problems and fix
them come with a better implementation i don't know if they didn't measure they didn't understand
they didn't compare or what it is but i personally wouldn't buy this at any price
you know 50 i can get a far better device than this thing and i just see no reason for this
to exist whatsoever yes at high impedance it will sound fine with high impedance headphones
and i'm sure all those uh reviewers online that gush over it are probably just using either very
easy to drive headphone or one that's high impedance and that defeats the purpose of
spending three hundred dollars because you won't spend three hundred dollars so that whatever
happened you buy in the future you don't have to buy this again this is not a ten dollar item
you throw away get another one um when you buy a new headphone um so uh and at a day rate there's
nothing that i can justify should cost 300 i think 150 is the limit of what you want to pay
thx onyx is 200 so a little bit of a stretch there but otherwise there's just no reason to pay 300
for anything it's not jewelry it doesn't it's not something you're going to show off to people
it literally shouldn't exist but exists and he sells strongly i think there were 2 000 reviews
on amazon alone and all those people are i guess they don't know about us and don't know about
the reviews i do and you know charts like this where so many better products exist in this one
and tend to go spend the money on this so it's a classic case of writing a brand and reputation
rather than a proper design the other versions of audioquest dragonfly don't do well either
by the way the red one is not competitive and the plain one is not either although they're at least
more in the ballpark than this one is they don't clip as easily as this and at least you
don't pay as much for them so really no reason to buy this anybody who gushes over it you know
i suggest not watching their channel read their reviews again because i tell you you throw away
all the measurements and just look at the just listen to it you hook up a proper headphone to
it and it's distorting uh it's just you know open and shut case uh on this thing got 300 dollars so
all rights hopefully uh you got something out of this review uh see you in the future one bye bye