JDS Labs C5 Headphone Amplifier


Pros: Design, build, sound
Cons: Packaging, not a micro-USB charger
A bit of preamble - I bought this C5 amp to go with my FiiO X5ii and Fidue A73 set up. The idea was to get the amp to reduce the noise floor and offer a bass toggle for when I felt I needed it. I wasn’t expecting (or needing) much of an improvement in sound quality or sound signature.
I'd asked for advice on Head Fi forums, but had no responses. I’ve since be told you need be extremely specific in your requests, or post something interesting!
So I based my purchase purely on trusted Internet reviews on Headphonia and Inner Ear, and based somewhat on availability. For the record, my shortlist was:
·      FiiO E12K Mont Blanc IEM special edition
·      Cayin C5
·      Aune B1
·      JDS Labs C5
What I really wanted was a ALO RX, but simply couldn’t afford. So out of my shortlist, the Cayin and Aune are/were not available in the UK, and I didn’t like the delivery options / costs open to me from overseas resellers. The FiiO seemed like the obvious choice, but despite UK companies having stock, it turned out the FiiO would come after the JDS Labs would from the US. So I opted for the JDS Labs for something a little different.
Buying it - 10/10
So the first issue was buying the C5. Unfortunately, there appears to be no UK resellers for JDS (if they are, they’ve switched on “discourage search engines” in their preferences! There was one on Amazon, but it simply states "Currently Unavailable", with no availability date or anything – really helpful, that.
So a direct purchase from JDS Labs' US store was necessary. I've had mixed fortunes buying online from overseas, but as JDS Labs is a reputable company using US Postal (the only thing they got wrong was Lance Armstrong!) and the delivery was insured, I wasn't concerned. I placed the order on the 23rd December, it was dispatched on the 24th (Christmas Eve, folks!) and a week later a well-packaged little amplifier dropped through my letterbox. A week is nothing but shipping standards - I ordered something from Currys PC World, the UK's equivalent of Circuit City, and it took 2 weeks to get to me (perhaps I was being taught a lesson as there is a store a 20 minute walk from my office). Still - a week at the busiest time of the year for an amp to come from the USA to the UK is excellent. Well done, JDS Labs and US Postal - you're already better than Currys PC World and DPD in the UK!
Packaging - 5/10
Inside the well-padded outer carton was the JDS Labs box. Now, having owned products from Apple, Samsung, HTC, FiiO, Rock Jaw and Motorola, I'm used to seeing good packaging. JDS Labs certainly haven't invested heavily here - a fluted cardboard box with bubblewrap inside does a good job of protecting the amp but does little for customer experience. Let's call it utilitarian. It works, but nothing more.
Design - 10/10
Once out of it's utilitarian packaging, it's clear where JDS Labs have invested. This is a beautiful product to look at and hold. I'll be honest, I'm not a fan of red. However, my Fidue A73 IEMs are red and grey, my FiiO X5ii is silver with a grey and red GUI, so I thought it would be a nice match – and I was right. But more importantly, the main body of the C5 is a lush red colour with a slightly coarse, matt finish that just exudes quality. The end caps are machined silver, which finish the product off nicely. That, coupled with the switchgear, this looks like a piece of high-end audiophile equipment rather than a polished consumer electronics product, say like the FiiO X5ii. Stunning, but only if you want that sort of thing. Personally, I love it.
Volume is a digital, but is controlled using a switch rather than a pot. It took a little getting used to, but works as well as the up/down volume buttons on the FiiO X5ii. Press it once in either direction and the volume goes up or down a step. Press and hold in a direction and it continues. I’d prefer a volume pot myself, but that’s just me and a very, very minor gripe.
Speaking of volume, I can’t hear any channel imbalance at lower volumes, although someone with better ears than me might. I do find it odd that the lowest volume is pretty audible and then the next setting down is off, not that anyone would want to listen lower than this volume I guess.
The on/off button and bass are lovely feeling toggle switches, and have a nice reassuring click to them. The charging port is the older style mini USB, not like the micro USB found in non-Apple phones and DAPs. This isn’t a huge issue, but it does mean if you’re travelling you’ll need to pack the mini USB as well as your phone/DAP charger. Everything feels really well built and solid though. I like it a lot.
There’s no gain switch. It’s MOSFET controlled. So there’s not a lot to report as I’m not an engineer, and the only listening devices I have are my ears.
Initial Sound Impressions - 5/10
When I first plugged everything in, there was a noticeably warm sound that the FiiO X5ii alone doesn't provide. However, everything seemed way too laid back. The detailing from the X5ii seemed to be swallowed up - everything was way too smooth and laid back. The vocals sounded behind the instruments, and I didn't like it at all. I was enjoying the music more from the FiiO X5ii without the amp more than with. It just sounded, well, wrong. But I persevered after reading about the amp's burn in time. 50 hours they said. So I waited. And waited. And waited.
And gradually, over time, the C5 went from "meh" to "marvelous".
Before I go on - a note about burn in. There are those that don't believe in it. Well, sorry but you're wrong. Maybe not every piece of equipment needs it, but some do. This amp's sound signature changed massively over time and definitely favours burn in. So there. Don't argue.
Burned In Sound Impressions - 9.5/10
Wow. My set up went from me preferring the sound of the built in X5ii amp over the C5 to no competition at all. The C5 though slowly grew into itself and began presenting a warm but wide, detailed and expansive sound signature that put all my music in a completely differently place. I have a list of songs I always use to test equipment out (http://www.head-fi.org/t/108584/the-best-audiophile-tracks-to-test-equipment/165#post_11519180) and I went through these songs to see how the C5 behaved.
I listen to a wide gamut of music, and it’s therefore very difficult to find equipment that isn’t too genre specific. The C5 seems to handle most genres well – but particularly acoustic singer / songwriter stuff like Ed Sheeran, George Ezra, Jamie Lawson et all. It’s warm, smooth playback brings a gorgeous texture to male vocals and separates them from the other mid frequencies beautifully. All this isn’t at the expense of treble or bass though. There is incredibly telling detail to be had from the C5, especially with my Fidue’s balanced armature design – although sometimes sibilance can be a factor (but nowhere near as bad as I experienced with my iBasso / Rock Jaw Arcana v2 set up). It’s never fatiguing, but sometimes you can wince a little.
Speaking of genres, one genre this little red box loves is dance. Oh, does it love dance. I don’t have a lot, because I’m not a massive fan. But I do have Ministry of Sounds 90s Anthems and I’ve never experienced dance music playback quite like it. Technotronic’s Pump up the Jam is incredibly well separated, with sound flying around the outside of your head. It’s a similar story with Gat Decor’s Passion. And if you flick that bass toggle… but more on that later.
But back to something more familiar with me, and Newton Faulkner’s Uncomfortably Slow. The guitar strumming in the intro is beautifully detailed, with great space and air. His voice is warm and well presented (and in front of the guitar), and the rest of the music arrangement is in layers behind his voice and guitar. Once the bass starts to come in, you get a gorgeous, rich sound that fills the space around your head.
Switching back to the FiiO X5ii’s own amp, and I observed that the warmth of the C5 goes, but the detail improves slightly. There’s something quite clinical about the way the FiiO goes about it’s business, and it’s a great sound, but I just like what the C5 adds in to the mixing pot. The FiiO is saying, “here’s the music, this is what’s been recorded, this is how it should sound”. The C5 then says, “yeah sure, but this is what you want to hear”. Don’t get me wrong, the FiiO is incredible, but the FiiO and C5 together is even better.
Snow Patrol’s “The Golden Floor” has many layers and a wide soundstage, and poor equipment struggles to reveal the subtleties and complexity of this song. The Fiio X5ii / C5 combo puts great depth between each layer and plays things nice and wide. Similarly with “Lifeboats” (from the same album) there’s some lovely layering going on. You just drift away with the song, even when you’re trying to listen in a critical way.
A note on volume - on higher volumes things can get a little messy, but this is volume that you might not need anyway – I certainly couldn’t listen to music at those volumes for an extended amount of time. If you need it that loud – either get your ears tested or invest in some noise cancelling gear!
Bass Toggle – 7/10
It’s a strange thing for me, bass. I do like hearing what the artist and producer intended to a certain point, in other words you’ll never catch me wearing a pair of Beats by Dre with the bass on the equalizer up to 10. But I do like to hear the bass. I like to know it’s there. I like it to be tight and punchy, with texture – underpinning the tracks as it were. Too much and it feels articifial. Too little and find myself pushing my earphones into my ears as if they weren’t in correctly.
The JDS Labs C5 has a bass toggle with has 3 options – off, medium and high. With the toggle in the off position, the C5 still delivers plenty of slam on Daft Punk’s Lose Yourself to Dance, and you never feel like you have to reach for the toggle here. On tracks that are bass light, such as Abba’s Voulez Vous, you are transformed to a 70s disco with deep, lush, rich bass that makes you tap your feet. And when rock or metal is the order of the day, such as the Foo’s Outside from Sonic Highways, the medium setting is just right to fill the bass line out nicely. But for the most part, I leave this bad boy in the “off” position, as it’s simply not needed. In some cases, the “High” setting is WAY too much for me, but I suspect bass heads will appreciate this.
It definitely works, and comes in handy. What’s beautiful about it is it doesn’t colour the other frequencies, nor does it drop the volume by a little. It’s either there, or not, depending on what you want.
Noise Floor
Surprisingly, I didn’t get the black noise I was expecting based on both the advertising and other people’s reviews. If anything, there’s a little more noise with this amp than with the FiiO’s in built amp. Maybe it’s just the Fidues, but there’s certainly a good degree of hiss going on. I can live with it, but I’d have preferred a completely black noise floor.
It’s always a gamble buying something you’ve never listened to before. Even more so when it’s such a subjective matter. I didn’t know what to expect with the JDS Labs C5. When I first turned it on I was disappointed. But it warmed up, and I warmed up to it.
It was a lush, warm, and smooth sound, but still manages separation and detail, and delivers fast and heavy songs with aplomb despite being so adept at the subtle aspects of music.
I can’t speak for other combinations of source and IEM / headphones as I’ve not really tested them. But with the FiiO X5ii and Fidue A73 it’s a glorious winning combination.
Actually, I’ve fallen in love with this little red box. I sometimes take it for granted and need to listen to other stuff to remind myself just how good it sounds (you get used to things).

I didn't realise! I googled it and couldn't find anything, and couldn't see anything in the instructions. I'll have a look :)
I owned the C5D and mostly used it a a Dac/Amp on my phone or laptop. One day i plugged my 
phono preamp into it and was blown away, the Amp outshined the Dac, 
The hiss i figure is with the DAC because when i used it as an DAC/AMP it was dead silent with
IEM down to 16 ohms. 
I'm looking for a nice portable amp to use with my X5II as well so this review helped my quite a bit. I'm using the Audioquest Nighthawk which at 25 ohm the C5 will have plenty of power, and a larger soundstage is what I'm after the most so the it will do nicely.


Aka: zardak
Pros: Neutral
Cons: Very little if any
This is quite simply a superb all-rounder. If you only need one superb DAC/Amp, then this will do the job nicely.

This C5D will give you what you want from the get-go.

Bass is beefy.

Midrange is clear and detailed, and neither forward nor recessed.

Treble is tonally accurate with no added harshness.

Soundstage is above average but some Amp/DACs are known to be 'slightly' more spacious.

The C5D certainly outperforms the FiiO X1 and X3 DAPs but has similar performance to the more expensive FiiOX5 DAP ($420). We just need an accurate DAC/Amp that doesn't change the music or add or take away for the sonic signature of the sound, the C5D does exactly this, with powerful 'clean' amplification and good dynamic-range, and the DAC translates the digital zeros and ones superbly. What more do you need?
That is a sponsors advertisement, i didn't put that their. There was a JDS-LABs C5. Amazon appear to be selling this. It's an older model i think. If you look closer at my review i've got C5D written.


1000+ Head-Fier
Pros: Highly transparent, Well built, Plenty of power
Cons: Greater than <1 ohm output impedance, Bass boost might be too much for some
First, I’d like to thank John Seaber at JDS Labs for the C5 review sample.
The JDS Labs C5 is the second generation portable amplifier designed by JDS Labs itself (replacing the outgoing C421) and is claimed by its creators to deliver “reference level performance”.
So does it deliver on its lofty claims or will it fall by the wayside? Read on to find out.

Design and Build Quality

Built with machined aluminum, the C5 is a very solid portable amplifier that feels like it could take quite a few knocks and keep going like a champ. The input and output jacks and the power and bass boost switches are very solid. The Volume control is different from the traditional ALPS potentiometers used on the O2 and CMoyBB in that it is a digital rather than analog potentiometer. JDS Labs claims this was implemented to eliminate channel imbalance at lower volumes. Unlike the lower end Fiio E11, the C5 can operate while charging.


The C5 comes with an instruction guide, a 3 ft. Monoprice USB cable and a set of rubber feet.

Gain and Hiss

The JDS Labs C5 has two gain settings, which are toggled between by pressing in the volume control and, at 2.3x and 6.5x, is almost identical to the O2’s stock dual gain configuration and should provide ample power for anything short of orthodynamic or planar headphones.
There was no discernable hiss when listening to the C5, even with my most sensitive earphones.
One flaw the C5 has is its 2.2 ohm output impedance and all sources should ideally have an output impedance of zero ohms so as to prevent impedance swings but most and headphones, even sensitive balanced armature earphones should be fine.
UPDATE: I received a point of clarification from John Seaber himself, which states:
As long as headphone impedance is 8x larger than an amp's output impedance, the amplifier's impedance is of no concern. So for our C5, the minimum recommended headphone impedance is 8*2.2 = 17.6 ohms. In actuality, 2.2 is a worst case scenario. This specification is generally <= 2.0, meaning even 16 ohm headphones are typically acceptable.

I rarely come across headphones or earphones with a lower impedance than 16 ohms so I assumed this would be a non issue for most users but seeing as I have an earphone in my possession right now with a low 12 ohm impedance (Sony's XBA-3IP), I should've mentioned it regardless. So, though the C5 has an output impedance of 2.2 ohms which admittedly isn't ideal, it may not be an issue for the vast majority of users, all things considered.

Battery Life

The C5 is rated for 11 – 14 hours and I found the real world battery life to be closer to the 11 hour figure in my tests.

Sound Quality

Fantastic. Plain and simple. Its frequency response is flat, there’s no hiss to be found, no ultrasonic crud to muddy up the sound and its transparency and clarity are top notch because of it. To put it simply, this is the best portable amplifier I’ve ever heard, and that’s saying something.
Where the C5 really shines is in its bass boost switch, which has become something of a hallmark of JDS Labs’ amplifier designs. With the flip of a switch, you get a significant but not overbearing boost to low frequencies that, in practice, sounds great. At 6.5 dB of boost at its peak, the bass boost isn’t for everyone or every pair of headphones but it is satisfying to use with my HD 600s and my HiFiMan RE-400 and RE-262s. It goes without saying that bassheads should be quite pleased with the C5.

Comparison with the Objective 2

Now I know that it’s hardly fair to include a $189 amplifier in the same category as amplifiers costing less than $100 so I’m not going to judge it head to head with those amplifiers. Instead, I’m going to compare it to the king of “portable” amplifiers, the Objective 2.
So, after listening to the two side by side, how does the C5 compare? Well, after hours of listening to the two, I’m hard pressed to tell a difference, which is the best compliment I can think to give it. Not only does it have the power to adequately power my HD 600s in step with the O2, its transparency is nearly identically excellent.
Granted, the O2 is technically a portable amplifier as well and does cost less than the C5 but due to its rather bulky design that’s not at all pocket friendly, I’d really only refer to it as a “transportable” amplifier. Yes, you can bring it with you and yes, it runs on batteries but the O2 is simply too big and cumbersome to work well in a truly portable setup. The O2 is the type of amplifier you bring with you to listen to when you have a desk or table nearby while the C5 pairs well with similarly sized portable players and fits easily enough in a pocket (as long as you’re not wearing skinny jeans).


Overall, there’s no doubt that the C5 is a very capable, powerful and transparent portable amplifier that sounds fantastic with every headphone I tested it with. It feels like a solid piece of equipment in the hand and seems worthy of its $190 asking price from the JDS Labs website. While I don’t think it’s quite on the same level as the cheaper (but less portable) O2, the differences between the two are minute and considering the O2 has been compared favorably with amplifiers costing many times its price, that’s saying something. If you’re in the market for an excellent portable amplifier, the C5 shouldn’t disappoint.
Re-Posted from my site, Musical Musings
Makiah S
Makiah S
-.- I asked John for a sample my self and well it was denied on the ground that it doesn't need any more reviews. NON the less I was able to purchase one today [New in Box Un Used] for $170. So I'll get that review anyways xD [and this one I get to keep]
Although I do admit, your pictures are excellent! I hope to one day have a arena to Test my headphones as nice as yours!


Previously known as 2Curiosity9
Pros: Clarity, Neutrality, Clean & Full Sounding, Sturdy Build Quality, Digital Potentiometer, No Channel Imbalance
Cons: Not a large enough Soundstage, Bass Boost is a bit too powerful, Volume Increments are a bit big per step of volume

Review on the JDS Labs C5

Fellow Head-Fi'ers, I am here to present you all with my first review on an audio product, the JDS Labs C5; so if I do anything that does not appear right, feel free to correct me, and let me know!

I'll also mention here, as I have done in the past with any of my "first impressions", that I am still fairly new to the audio scene, and I cannot ensure you that my "review" will be as detailed and in-depth as one might suggest, but all in all, I'll give it my best, and hope you all enjoy it:)


So, recently I have been in the threads, seeking a new portable amp that would be my first amp to kick off my start in mid-tier audio, as I felt that I was done with low-end, and had the sudden urge to move on slowly. After a week or so of reading reviews here and there, I had ended my hunt with the JDS Labs C5, since the reviews and opinions on it were very positive, and I had yet to encounter any statements saying anything majorly negative about it. This amp was well within my price range, was highly reputable and had the sound signature that I was after - so I guess you could say, it suited my situation nicely. 
Anyways, I had bought the C5 a few days ago from Noisy Motel, and to my surprise, the amp had arrived within 48-hours after payment! I'd like to give a shoutout to them, as they provided me with first class customer service during the process of my purchase, and and answered all my questions swiftly without hesitation. I was very satisfied:)
Now onto the unboxing...



Upon receiving the C5, I took a few photos of the amp in most of its perspectives to show you guys (who have yet to see what the amp looks like in detail). 

Here, you have the box that the JDS Labs C5 comes in.

Another angle of the box.

Yet, another angle of the box, with the Noisy Motel sticker enclosing the product.

Side view of the box, with the briefings (The other side has nothing on it).

The bottom of the box. The world must know it was made in the U.S.A! 

The opened box and its internal presentation.

What is inside the box: Micro USB to USB charging cable, instruction manuel, and the C5 (enclosed in the anti-static bag).

A quick picture of the specifications and operation conditions.

The Monoprice Micro USB to USB charging cable.

Four clear rubber feet for the C5.

The C5 enclosed in the anti-static bag. (You can faintly make out the logo.

Release the Kraken! 

The beast from within the packet. It has the obvious, JDS Labs logo on one side of the amp.

Angled view of the amp.
(All pictures were taken on the HDR settings on an 8MP LG Nexus 4 with no effects)
As seen in my quick unboxing, a sufficient amount of accessories have been included, just the main ones, nothing more. Overall, it was fairly basic, and the box housing the amp and accessories was just a regular cardboard box. 
Now, onto the review...



  1. Frequency Response : +/- 0.02 dB
  2. THD+N (20-20kHz, 150 Ω): 0.0009%
  3. THD+N (20-20kHz, 32 Ω): 0.0045%
  4. Noise: -105 dBu
  5. Crosstalk @ 150 Ω: -67 dB
  6. Inter-channel Phase @ 1kHz: +/- 0.01°
  7. Channel Balance: +/- 0.55 dB, all volume positions
  8. Max Output @ 600Ω: 4.146 VRMS
  9. Max Output @ 150Ω: 3.337 VRMS
  10. Max Output @ 32Ω: 1.010 VRMS
  11. Power Supply: 14.0 Vpp
  12. Output Impedance: 2.2 Ω
  13. Battery Run Time: 11-14 Hours*
  14. Charge Time: 2 Hrs to 80%, < 4 Hrs to 100%
  15. Operating Temp: –40°C to 85°C
  16. Operating Humidity: 0 to 85% Rel. Humidity
  17. Dimensions (excluding switches): 99.5 x 61.5 x 14.0 mm (LxWxH)
  18. Weight: 4.2 ounces 

    Test Equipment: PrismSound dScope Series III audio analyzer, Tektronix TDS1012.
    *Run time may vary based on equipment and listening style.
(Copied from the JDS Labs' official website: http://www.jdslabs.com/item.php?fetchitem=70)

Build Quality & Design/Function Factor

Build Quality

The build quality of the C5 has a very nice construction as it obtains the appearance of elegance, and shows that it was built to last. The body of the C5, has a matte black metal finish (if you got the black version) that is very solid, and is overall, sturdy. It feels very nice in the hands, and does not have any sharp edges or anything that would give discomfort to the user. 

The 3.5mm sockets of the input and output of the amp, are slightly recessed into the amp, to allow the fitting of large male 3.5mm jacks. When inserting a jack into the sockets, the sockets are very tight, so it might take a bit of a push to get it in there, but at least you know it'll hold the jack in place, firmly. The sockets will take a slight bit of effort to pull the 3.5mm jack back out, so that will ensure that the jack won't be going anywhere once plugged in! None of that sliding-out action. 
I did, however, notice that the charging Micro USB port on the amp is a little tight, were it took a pinch of force to get the Micro USB cable into the amp to charge it. Not a bad thing, but it just felt a bit too rigid and tight.

As of the switches of the amp, the On/off switch, and the bass boost switch, have a high-quality feel, which is obviously not like any of those cheap switches that feels like they're going to snap or break. They have a strong click upon switching it, so I guess you could say it's reassurance that you bought a well-built amp with quality materials. 
What's new to me, is the new digital volume control (potentiometer). Although it's new to me, it is without a doubt, a very cool feature of the C5. Has a nice feel when increasing/decreasing the volume, and the click to switch to high/low gain is also a nice addition, on top of the already cool, potentiometer. 

The faceplates at each end of the amp has a brushed aluminium finish, with a heavy-duty feel that is around 0.2mm thick. The plates are removable via two screws, one at each end of the plate, to remove/change the position of the internals of the C5. I unscrewed the screws, minutes after receiving the amp to flip internals so I could have the JDS Labs logo facing down, as I was going to apply Dual Lock to the amp so I could adhere it to my audio players.
Here are a Front and Back view of the faceplates of the C5.

Front View^

Back View^

Design/Function Factor

(I realised this part was basically me blabbing on about the digital potentiometer the most, so I wish to apologize in advance, haha)
I found the design of the JDS Labs C5 to be quite elegant, yet still maintaining its classiness for its role. The amp, although very simple looking, is quite amazing when it comes to a sleek and compact design. Sleek, by all means of the recessed 3.5mm sockets and screw holes to the low profile switches and digital potentiometer, as opposed to the usual, large and protruding volume control pot. In no way, am I saying that the volume control pots are a bad design or anything, I'm just simply saying that JDS Labs did a good thing by applying the use of a digital potentiometer, that does not protrude out, or is easily adjusted by accident. Another thing about the digital potentiometer that I absolutely adore, is that it has eliminated the common channel imbalance problem, which is the usual case with the volume pots. Not only that, it also remembers your last high/low gain settings and volume setting, so you do not have to readjust to those desired positions when you use your amp next. The potentiometer has 63 steps of volume, inclusive of the silent step, which gives the user, a good amount of volume options to choose from. I might be a bit nit-picky here, but I think the volume increment of the potentiometer is a bit big for its own good. It would have been great if JDS Labs could have made the increments a bit small, so the majority of us users, could utilise the balanced volume at lower listening volumes. Other than that, I was well satisfied with the digital potentiometer. I know, that the potentiometer can be programmed to run at your desired volume increments, but I am not one to venture into the territories of the "DIY/playing with the internals of a unit" area. As of that, I will have to live with the C5's volume increments as is:)
Apart from the digital potentiometer, another fancy feature about the C5 is that when it is nearly out of batteries, the power light will begin to blink continuously, so you will always know when it needs to be charge, before its 14 hour usage time ends. I thought this was a cool feature, as there are many amps out there without an "I-Need-To-Be-Charged" indicator, hence  it will then result in a randomly dead amp during usage. When on and at full battery, the amp will display a GREEN light; when in need of a charge, it will be a BLINKING GREEN light; and whilst it is charging, a BLUE light will be displayed.
Anyways, here is a picture of the C5 in the palm of my hand. It's pretty small, compared to what you see in images of it.

In short, the JDS Labs C5 has the regular appearance of a portable amp, but unlike some of the other, retangular prism amps, this amp has a well thought out design, which gives it the sleek and elegant look. I can say that the design and build of this amp, is surely up there competing with the other well-built amps of the higher prices!

Sound Quality


Okay, so this is the part I'm not too good at, so please bear with me:)
(I used my V-Moda M-100's and Colorfly C3 for this part - High gain ON, NO bass boost)
I understand that many people have compared this amp to the O2, but unfortunately, I do not own that amp. Instead, I will be comparing it to my C&C BH, which I am aware, a few owners of that amp are interested in the C5.
In general, to me, I found that the C5 had an overall feel of a clean sounding amp with almost crystal-clear clarity, well-refined detailing, and its amazingly presented, neutrality.

This amp, does not have a warm touch to it, nor does it sound too bright, hence the neutrality I had mentioned. The clarity is one of a kind with this amp; you can hear its full sound without a sign of hissing, which applies to low volume as well as medium-level volume, and I have yet to try maxed volume. I must admit, the detail and micro detail of this amp is really expressed well, as you can make out most of the micro details, such as the ending of the snare in some songs with drumming in it, or something like the "ting" of a triangle used in the far background - something you usually wouldn't notice when listening regularly.
As of its clean sound, I can easily say I have yet to hear anything like it. The sound it produces is just so clean and crisp, it makes my low quality songs (yes, I still have a few) sound as if they were of high quality with none of that warm vibe in the background. The crisp sound it produces makes the tune sound somewhat fresh, and it really just feels like starting off a beautiful morning with the breeze gently blowing across your face. Kinda like a splash of water to the face, where you get that cooling sensation. Haha, yeah, I apologize for my weird wording ways, as I am still new to this, as I had mentioned many times before:)
I shall go onto attempt at the Lows/Mids/Highs. Once again, bare with me!


I found the mid bass and sub bass on the C5 to sound rather satisfying - not too aggressive, nor too soft; just right to me. It has a good punch, which adds to its crispiness, and it has a fulfilling texture to it, similar to the melting of butter, as my friend once put it as for those moments. The bass boost switch for this amp was really a bit of a hardcore basshead thing; the bass it produces is thunderously earth-shaking, as I found it was way too impactful and was somewhat, headache-worthy. However, it is good for the occasional "I'm feeling like a head-banger moment"! Wasn't a fan of it still, but with the bass boost switch off, I enjoyed it as is. 


I found the mids of the C5 to be quite forward, as opposed to recess. It does come out at you and makes the vocals sound very full and makes it as if the singers were there before you, performing on stage, singing towards you in third row, although I feel that the soundstage of the C5 is a bit congested, could do with a bit more air and a wider soundstage. I believe "engaging" is the term, that should be coined for this? I think so. The level of detail here is fine, as I had stated above, but I found that the instrumental separation could have been better. It just didn't have the layered effect when I come to think about it. It can have the smothered-feel on that part. 


The treble of this amp to me was quite satisfying. This was the part where it gave me the feel of crisp sound, as the highs to me, were excelled pretty well. Not the best, but it could do with a bit more tightness.

Comparison to the C&C BH

(This one's for my fellow Head-Fi'ers in the BH thread) 

Haha, where do I start...

Sound Comparison

In short, I found that the C5 was superior to the BH in terms of clarity, cleanliness, fun & engaging sound, detailing, and balance of warmth and brightness, aka. neutrality.
The BH has it over the C5 when it comes to the wide soundstage that the BH has, along with the BH's top quality instrumental separation, the good ol' cheat switch of the BH, the infamous, LF switch (The bass/treble booster), and the glorious 100 hour battery life of the BH still remains king of the hill. 
So to sum things up for this comparison, I think the C5 has it in some ways, and the BH has it in another. Does indeed, come down to preferences, but the BH to me, does take it when the price-to-performance ratio is taken into consideration. 
Now down to the question that most of the BH owners would be wondering, is that, "Which do you prefer?"

Well, as of now, the C5 as my "New Toy Syndrome" has yet to wear off! 
I will touch up on this later down the track. As of now, I cannot confirm yet.

Size Comparison

Side-by-side (Birds eye view)^

Front-on view^

BH on top of the C5^

A side view of the BH on top of the C5^
UPDATE (2 Nov. 2013): I have recently bought a iBasso DX50 to go with me C5, and the pairing is fantastic! I shall provide some of my opinions and thoughts on this pairing below.

Pairing with The iBasso DX50

(Here is my current rig, consisting of the V-Moda M100, JDS Labs C5 and the iBasso DX50)
I'm back again, to add this small segment, to let you guys know about this pairing, as I am sure there are a few of you's out there who are still deciding which amplification device to buy to pair it up with your DX50. 

Sound Quality

Well, in short, upon pairing the two devices, the DX50 and the C5, I felt like it had improved the sound quality over the Headphone Out of the DX50. All of which, I will mention the main highlights of this combo in which had stood out to me the most. I found that the soundstage of the DX50 had widened a little bit more in comparison to the not-so-large soundstage of the HO (Headphone-Out) of the DX50. I also found that after adding the C5, the mids and vocals are fuller-sounding - thick and much smoother. Treble turned out to be a touch more sparkly and glimmering over the HO, and I also found that the detailing when amped, was much more clearer define, and required less effort to pick out the micro-detailing of tracks. What stood out to me as one of the biggest improvements, was the lows. Upon switching the Bass Boost switch ON; this rig really shined for a basshead (although, I wouldn't consider myself one, but you get the jist). When the switch is on, the bass' punchiness and the sub-bass vibe is very strong. You can pretty much feel it penetrating straight through your ears, and right into your brain (Sorry for the exaggeration!). It is much more textured than it was before, and the kick that it gives is pretty phenomenal. Before I used the Bass Boost switch on the C5, I always thought it would be too overpowering, and hence, distort/muffle the bass, but I was wrong. Really wrong. The bass had never hit harder, whilst still holding its cleanliness for quality.
That should do for my impression on the DX50/C5 combo, but then again, I have yet to play around with other amps, such as the D42 from iBasso, or the C&C BH1/2, so I can't confirm that the C5 would provide the best pairing, etc. I'm sure there are better amps out there that could drive the DX50 to a better altitude, but for around the $200 mark, the C5 certainly does well. 
Aside from sound quality, I'm sure most of you guys (or just some of you guys...) will be interested in the pairing's size comparison and fit. I am proud to say that the pair exceptionally well, considering the C5 is pretty much, a footprint of the DX50. If I remember correctly, the DX50 may have been 2mm wider than the C5, or it may have been the other way around - but do correct me if I'm wrong. 
For those who are wondering how the DX50/BH sounds, compared to the DX50/C5, I am unable to provide that impression as I had sold my BH before I had acquired the DX50. My apologies! 

Also, I should also mention that the C5 has amazing synergy with the V-Moda M100's. The synergy of the two is pretty crazy, I'll say, now that I've used the two more often. 

Size Comparison of Pairing and Fitment, Along with some Photogenic DX50/C5 Combo Shots

The DX50/C5 bathing under the sun
Side view of the DX50/C5 combo^
Bottom view of the DX50/C5 combo^
Top view of the DX50/C5 combo^
Birds-eye view of the DX50/C5 combo^
Hopefully, this addition of photos and a few words should be enough to show some DX50 owners what the C5 when paired with the DX50 is like. 
Sorry for the dust that can be seen on the rig and amp bands, haha. I've been taking pictures of the rig on carpet, so that's the results of that! 



So here I am...ending my first review:) Never thought I could pull it off, honestly, but I managed in the end, haha.
Ultimately, I found the JDS Labs C5 to be a brilliant little amp that had a lot of positive attributes to it, along with an elegantly sleek design, that was very appealing to my ears and eyes. This amp has surely made my music listening experience much more enjoyable, and ever since I started listening to it, I have started to appreciated some of my songs that I had never been too fond of before, so that really says something about this. Call it placebo or whatever you want, but I found this to have great synergy with my C3 and M-100's, and the audio that it generates, really puts me in the soothing mood as well as giving me very enjoyable listening sessions late at night. This amp, to me, is what defines neutrality when I listen to it.
Briefing Before I Leave
Now that this review is done, I'm going to need a break from four and a half hours of typing and thinking. 
If you've read it from top to bottom, I'd like to thank you for putting in the effort to reading a novice's first review:)
Greatly appreciated.
I am so done here. 

Going to enjoy my rig now!
Over & Out,
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@drbluenewmexico Thanks!
Hmm..I wouldn't say are "class A" amps, but I would definitely recommend the BH for the C3:) That pairing has some sort of wild synergy between the two, to me.


@drbluenewmexico Hmm, about the opamp changing. I, myself, am not too sure if that's possible, so I cannot tell you whether or not, it will clarify the sound.
I prefer the C5 at the moment (Still having the "New Toy Syndrome") when paired with my M-100, as it takes my M-100's to its fullest. The C5 has more power, better clarity, and has an overall cleaner sound to the BH, but the BH does excel in some areas such as the soundstage width, etc.

@5thDinasty Each to their own:)
I realised it masked a tiny bit of micro-details, but not completely.
Hmm, you could always put the amp up for sale on the boards? I'm sure there will be someone who'll be happy to buy it.
At the end of the day, it really comes down to preference as to what you prefer, but I haven't tried all that many amps before, so this for a low/mid-tier is pretty decent.
Nice review. A pity you missed the opportunity to add dx50/BH to it.
A pity indeed, but I'm rather pleased with the C5 at the moment:)


Headphoneus Supremus
Pros: Similar sound signature to the Objective 2, re-programmable digital potentiometer, bass boost, engaging midrange, little to no channel imbalance
Cons: Situational bass boost, fatiguing at times, volume increments are a *bit* too large
Okay, a serious question not related to the review: what is the difference between the "Audio Quality" rating and the "Quality" rating, and how is the "Quality" rating different from the "Design" rating? 
 *scratches head*

Anyway, back to the review.
I did a video review for the C5 on YouTube if you are interested in an auditory/visual review:
What's in the Package?
  1. JDS Labs C5 wrapped in an anti-static bag
  2. Mini-USB to USB 2.0 cable with gold connectors
  3. 4 clear adhesive rubber feet
  4. JDS Labs business card
  5. User manuel with objective measurements
It's a pretty basic package, but it gets the job done. The C5 also comes with the standard JDS Labs 2-year warranty against manufacturing defects.
I did an unboxing video on YouTube if you are interested (probably not, hahaha).
Custom Orders
There are also 2 things you can get customised when your order your C5; all you need to do is fill out the "order notes" section before you make your purchase:
  1. Specify if you want an alternative endplate colour (black or silver, as shown in the images below)
  2. Specify if you want a custom laser etching (in the images below, the text to the left and right of the JDS Labs logo were custom ordered)
^ those were not Photoshopped
I would say the C5's design and user interface are near perfect as a portable headphone amplifier for my preferences. There are 5 things I don't like about the design, but all them are pretty minor to me:
  1. There are 2 places that I know of where cell phone coverage is very poor/non-existent. In these areas, when the C5 is connected to my iPhone, I encounter some RFI noise (the *boo boop, boo boop, boo boop, boo boop, boo boop* sounds). However, I have only heard this noise with poor/non-existent cell phone reception, so you probably won't hear this noise with normal use.
  2. The battery life lasts around 10-11 hours from a full charge in my tests. It's enough for me but others might want a few more hours from their portable amp.
  3. The "low gain" is a 2.3x gain, which can be too loud for quiet listening sessions when using sensitive headphones/earphones.
  4. The potentiometer's volume increments are sometimes too large for me and I would prefer to have something between the 2 volume steps
  5. The bass boost is pretty substantial and there is only 1 setting for it. Perhaps a 2-setting bass boost would have been more appropriate. *see the bass boost section below for more details*
Now on to the good things about the C5's design:
  1. The C5's battery can fully charge from an empty battery in around 2.5 hours
  2. The digital potentiometer is very well implemented and can be re-programmed (the potentiometer is pretty flush against the frontplate so it's hard to accidentally adjust the volume in your pocket; the gain is also toggled by pushing in the potentiometer)
  3. The potentiometer has very little, i.e. non-audible, channel imbalance even on the first level volume (there are 62 levels of volume, 63 if you include mute)
  4. There is very little background hiss with the C5 under normal volume levels (at higher volume levels you can hear a slight hiss when you adjust the potentiometer)
  5. The C5 loads the volume and gain settings from the previous session upon turning it on
  6. The switches are all very sturdy-feeling and they have a very satisfying *click* sound when switched. No cheap-feeling switches here.
  7. The source and headphone inputs are both on the front plate but spaced far enough apart that cables don't get in the way of the rest of the front-panel interface. The headphone jack is closer to the outside, so right-angled jacks have more freedom to rotate.
  8. The PCB itself can be re-oriented within the C5's enclosure due to the rail system inside the case
  1. The size of the device itself is small and pocketable. It's a bit thicker and wider than an iPhone 4S, but shorter in height.


  1. The aluminum enclosure has a matte-finish with a texture similar to that of a chalkboard (not a fingerprint magnet)
As a whole, the C5 sounds very clean, detailed, and clear, similar to the Objective 2 (my current reference amplifier). It is the cleanest-sounding portable headphone amplifier I have heard so far and I think it is well worth the $189 USD investment.
Here are my comparisons between the O2 and the C5:
  1. O2 gives the sense of a larger soundstage with more air between instruments (a school cafeteria); the C5 sounds more boxed-in (a school classroom)
  2. O2 sounds a bit more dynamic; the C5 sounds a little duller (not boring dull, but instruments don't sound as "full" and don't offer the kind of grand sound you get from the O2)
  3. O2 has a more laid-back upper-midrange/lower-treble (relative to the C5); the C5 sounds a bit brighter and more fatiguing
  4. Relating to the above point, the C5 has a midrange that is is a bit more forward and engaging; the O2 sounds more laid-back
To sum it up, the C5 sounds like a brighter O2 with a more forward upper-midrange and the soundstage, both width and depth, are reduced; hence why I call it the O2's younger sibling. For a portable headphone amplifier, I think the C5 does very well for what it is in terms of sound and I would recommend it to someone looking for a reference portable headphone amplifier in the ~$200 USD range. I actually prefer the more upfront upper-midrange of the C5 at times compared to the O2 since they are more engaging to me and I often have the urge to sing along to the music (in comparison I would just listen to the music with the O2).
I forgot to mention, but the high gain mode has a slightly different sound profile from the low gain mode. The bass becomes a bit boomier and the treble becomes a bit softer. If you're looking for a less fatiguing listening experience, this is a great option if the higher gain (6.5x) isn't a problem for you such as when you're mobile listening. The difference in sound is more noticeable when you compare the C5 with low gain and bass boost on to when you have high gain and bass boost.
Speaking of the bass boost, I think it would be appropriate to describe how it sounds. If you've heard the digiZoid ZO2 before, the C5's bass boost is similar to a green-yellow setting from what I recall in memory. In layman's terms, it's a very deep and substantial sub-bass boost. It won't be for everyone due to its large increase in bass, but I didn't find it to colour the midrange all that much, similar to the ZO2. Despite the large bass boost, I actually do use it while mobile listening with the V-MODA Crossfade M-100 since it provides that extra bit of bass to enjoy even on a noisy bus ride. It's the kind of bass I call "theater bass" since it gives you the sense of bass rumble one would experience in a movie theater. The C5 + bass boost + AKG K 701 = awwwwwesome movie-watching experience
Re-Programming the Digital Potentiometer
Now this is a unique feature that I haven't heard about in any other piece of audiophile equipment before. I'm sure there's something out there that has such a feature, but I personally haven't heard of any.
I made a video on YouTube explaining this process and at the end of the video I demonstrate how I modified the C5's potentiometer:
By using an ISP programming tool in conjunction with Arduino software, you are able to re-program how the C5's digital potentiometer behaves. Unfortunately I have not gotten this process to work in Windows 7 (both 64 and 32-bit), but I did get it to work in OS X Mountain Lion (I am running version 10.8.4). It is possible to solder a surface mount LED onto the C5's board but I since I don't have a soldering iron small enough to do the job, I decided to utilise the C5's existing power LED.
You will need the following to re-program the C5:
  1. Straight header pins with a spacing of 2.54 mm (you will need 2 rows of 3 pins)
  2. ISP programmer
  3. ISP programmer drivers and/or software (these drivers are available for Mac only)
  4. Ribbon cable to connect the C5 to the ISP programmer
  5. Arduino software
Before you can re-program the C5, you need to solder the header pins into the PCB. Additionally, the header pins are too long to fit within the C5's enclosure, so you will need to trim them slightly. Slightly trimming the pins should not affect they're ability to connect to the ISP programmer.
When connecting the ISP programmer to the C5, make sure the orientation of the cable is correct. In the image above, the pin labeled 1 on the PCB corresponds to the red cable in the image below.
You can download the firmware/code for the C5 from JDS Labs' C5 blog post (they are releasing the firmware under a Creative Commons Attribution-ShareAlike 3.0 Unported license):
If you haven't programmed in Arduino before, such as myself before looking at the C5's code, the programming language is similar to C.
Long story short, I re-programmed the C5's potentiometer such that I have 3 modes of operation (for an actual demonstration of these 3 modes, please refer to the YouTube link I posted above):
  1. Low gain mode, normal volume speed toggle, no flashing LED
  2. Low gain mode, slow volume speed toggle, fast-blinking LED
  3. High gain mode, slower volume speed toggle, faster-blinking LED
In addition I have the C5 set the gain and volume levels to low and 1 respectively so I don't blast my ears if I had loud volume levels during the last listening session.
Why slower volume speed toggles? To allow a more precise volume adjustment while holding the potentiometer down (which I do in my pocket when mobile listening).
Why blinking LEDs? To have a visual indication of when I am on a different mode
All in all, I really do find the C5 to be a fantastic portable headphone amplifier in the ~$200 USD range. It sounds fantastic and is reference-worthy in my experience; the bass boost does wonders depending on the headphone, music, and listening environment; the unit itself can be customised specifically for you with a laser etching; the ability to re-program the digital potentiometer is a novel concept to me for audiophile gear and I think it can lead to some very cool results if you spend the time tweaking it (as demonstrated above).
To bring this review to a close, I have had some of the best customer experiences with JDS Labs since they are quick to reply to any e-mails you send them and their responses are very helpful and direct. Whatever the "Quality" rating is for the review details, the customer service of JDS Labs deserves some recognition and that in part is why I gave the quality of the C5 a full green bar.
Thank You!
Thank you for taking the time to read or glance through my review! 
The AKG K 701 is rated at around 62 Ω, instead of 300 like the HD650, but yes I find the K 701 to sound great with the C5. The C5 should be fine with the HD650 though if you're looking for a portable amp to drive them.
Audio addict19
Audio addict19
Okay thanks for the response! Are you sure it should handle it? My E11 only gives it 30Mw right now and i think it needs a little more oomph to get a better sound.
From JDS Labs themselves:
"Correct, C5 is well suited for all of your headphones. Your HD-650′s are 103dB/mW @ 300 ohms, so they need about 16mW. C5 delivers 28mW into 600 ohms. This means it will provide more than twice the necessary power into HD-650′s."

From a calculated value:
300 ohms: V = 3.836 Vrms, Ipeak = 18.1 mA, P = 49.0 mW

A power value of 49 mW at 300 ohms should be able to drive the HD650 just fine (up to 115 dB SPL).

From FiiO's E11 webpage:
Drive ability 16~150Ω(recommend)


Headphoneus Supremus
Pros: Sounds very, very good, solidly made, nicely engineered
Cons: Perhaps too few steps in the volume control
It's a solidly made piece of gear that sounds very, very good.
To my ears, at least as good as the O2 - a well known
reference by now. Perhaps slightly more openness
and clarity. The size is very reasonable; about 100
X14X60 mm.  Sound is smooth, soundstage is 
full (though not overly so); no harshness at all.
Only issue for me is too few steps on the 
volume control.
Well worth the selling price.
And, worth mentioning, the customer service
of JDS Labs is exceptional.


1000+ Head-Fier
Pros: Excellent build Quality.Digital volume makes for excellent balance at low volume. Drives my Westone 4R and Sennheiser HD 800
Cons: Non as yet
I have had several Headphone Amps over the years.This one is the best so far. At the moment,the C5 is used with an Ipod and Iphone and also tried with my home (large!.) Headphone set up..I have used this Amp,with and without Eq. It paints a very detailed picture,and only add  a not too forward,but just about right presentation. It gives a fairly wide soundstage,and does not seem to colour the sound at all.The volume Control has many steps,meaning that you can always get the level you require. The Bass boost adds volume,but not at the cost of Clarity. I do not think anyone would be disappointed with the C5.It seems to get better the longer I use it. These comments apply to me,and the way I am hearing it.


100+ Head-Fier
Pros: Power, Design,Color, SQ, 60 levels of Volume (That's what I Heard from Local Dealer)
Cons: Little big, Lose of High and Low gain switch.
[size=10pt] [/size][size=10pt]I had listened to C421 which is JDS's previous portable amp[/size]
[size=10pt] [/size]
[size=10pt]What I see with C5 is Simpler function yet compact. It sounds like they cleared up[/size]
[size=10pt] [/size]
[size=10pt]some noise that C421 had. and some other problems(Output Impedance)[/size]
[size=10pt] [/size]
[size=10pt] [/size]
[size=10pt]Bought from Headphone Bar and There was 3 guys including store owner and me[/size]
[size=10pt] [/size]
[size=10pt]were comparing it with Schiit Asgard, LYR, Barson 160HD, Soloist.[/size]
[size=10pt] [/size]
[size=10pt]with HD800, LCD-2, PS1000, He-500[/size]
[size=10pt] [/size]
[size=10pt]What we found out is C5 is really powerful and there is nothing better under 500 AS portable.[/size]
[size=10pt] [/size]
[size=10pt]C5 was able to Run HD800 with 24 levels out of 60 levels of volume. LCD-2 was 25, PS1000 was only 14![/size]
[size=10pt] [/size]
[size=10pt] [/size]
[size=10pt]Sound wise? C5 sounded as good as Asgard. 3 of us could not believe it was just portable amp.[/size]
[size=10pt] [/size]
[size=10pt]It has little warmer sound but not too warm like Asgard. It does not lose any details through whole FR range.[/size]
[size=10pt] [/size]
[size=10pt]I do find My Edition 8 has little warmer and richer in sub-bass when I compare it to E11. All the details are there as I put in in to Asgard and [/size]
[size=10pt] [/size]
[size=10pt]LYR. [/size]
[size=10pt] [/size]
[size=10pt]Staging was increased comparing to E11. Not as wide as regular indoor headphone AMPs but One of the biggest on this price range.[/size]
[size=10pt] [/size]
[size=10pt]I do recommend this to who are looking for better portable amp than E11 but not willing to pay over $300 ( I haven't but you might able to find some good portable amp for $300).[/size]
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Great review; because it's straight to the point with the comparison to the E11, good job!
unless by "bomb" you mean that this is a fake shill review that should not be heeded... I thought it was just bad grammer....
Yeah man this was great thank you. You convinced me to buy one and Im glad to hear this is just as good as the much more expensive shiit gear, Idk about others experiences but my customer experience was awful.