This is my second attempt at using a portable amp (I returned my Fiio E12A for this).
 
That was a good decision. The Cayin C5 is an absolute powerhouse. It can power IEM's and earbuds (what I use it for), but also large size over-ear headphones. I am very pleased by the sound. It is slightly warm with a really expansive 3D soundstage. But by far the best feature is the bass boost; the sub-bass really slams. The amp can also charge your other devices (like your phone etc.) which is an added plus. I got the black edition which aesthetically looks great.

I used it with my Astell & Kern AK Jr. player and Rose Mojito high-fidelity earbuds.

 
 

The Good.

 

1. It's an amp and it's job is power and it's got a lot of that. I would think it was more powerful than the e12 though the specs say otherwise. Bass boost matches graph
2. Bass!!

 

Bass switch demo

 
Source was an X5 using this slope on Low Gain

 
 

 

More Good

 
Overall sound on normal listening with a different or no eq and a pair of open back Sony ma-900 reveals that the hype was right. Out of the box it has a wider spacial presentation not found on the e12.
 
 
 
 
 
 
 
 
 

The Bad

 

1. Getting an amp  20-30% more expensive than the e12 that has no mini to usb like the e12 comes with is unacceptable
2. The volume which is numbered in off brown/champagne on a cream (not white) wheel is very hard to see. It's under a plastic cover...fine. MAKE IT READABLE 
3. Blue? Really?.....blue. Thick blue straps (e12 has black and I got 4 and I got a normal ready to charge setup.)

 
 
 
 
 
 
 
 
 
The e12 is the amp I built the Extremebasshead thread with which will soon be the largest Head-fi has ever seen. As powerful as that amp is the Cayin C5 puts out what seems like more power as it seems to be cleaner/wider and the bass slope is elongated. I can sculpt a bass curve with an eq and the C5 gives me quite a hill to carve.
It is the new official amp of the Extremebass thread. The amount of e12's moved by that threads rec/video displays is a large number. I have to explain the weakness of the item to as they say "Keep it real". I expect folks wanting a wider stage (How does an amp change staging??) I dunno but the e12 clearly sounds more closeted when compared directly with the Cayin C5
 
 
I think the mini to mini cord is a joke and the blue rubber and numbering on the dial...if it's gonna sit under a shaded tree (plastic) should be bigger with better contrast
 
 
 
 
Rocky start but I think the long term will prove to be quite fruitful for my ears.
 

 

I am penning down my opinion about the ‘most-buzzed-about’ C5 amp. I will try to keep this review simple as possible and I hope it would be easy to read, and will help fellow enthusiasts to know more about the mighty C5 amp.
 

 
 
 
Me : I am an 21 year old Engineering student living in a small town in India. I would like to call myself an music enthusiast, rather than an audiophile.
 
I was inspired by music since childhood, and as the time passed, the passion of music grew in me, and that subsequently led me to join Head-Fi. Eventually, I found the pleasure of listening to music mainly by the HD600 headphones, and realized the true components of recorded music. I usually like to listen to Indian Classical Music along with Bollywood songs.
 
 
Intro :  Spark Audio used to be a subsidiary electronics department of the Chinese Air Force. Its association with tube electronics and dates back to the old days when aviation technology employed vacuum tubes. After its privatization in 1993, Zhuhai Spark electronic equipment ltd. decided to apply its technical expertise into consumer audio, and has become one of the most reputable audio companies in China. It designs, manufactures and markets its own products under the name “Spark” in China.
 
 
“Cayin” is a brand under Zhuhai Spark electronic equipment ltd. They mainly manufacture desktop and tube amplifiers. Cayin was not renown to most of us, until it released its famous C5 portable amp. C5 is the flagship portable amplifier offering from the house of Cayin.
 
 
Packaging and Accessories : The C5 arrives packed inside an simple yet rigid golden coloured classic cardboard box. The box is plain with only ‘Cayin’ written over it. The box has an slide-able sticker, which needs to be slid to one side to lift off the lid of the box.
 

 

 
Once the lid is lifted off, The C5 is seen to be resting on an pseudo-base, packed inside an soft cover. The pseudo-base can be lifted off to reveal the storage compartment, in which all the included accessories are present.
 

 

 
 
List of accessories in the box, which include the following:
 

 
1) 3.5mm interconnect cable: For attaching to an DAP, as its of short length and connects are 90 degree angled.
 
2) Micro-USB interconnect cable: To utilize the power bank feature of the C5, by connecting to DAP or smartphone.
 
3) Rubber feets: To attach to the C5 amp for getting better grip and for avoiding scratches.
 
4) Rubber bands: For binding the C5 with the DAP. Hence attaching them both as one whole unit.
 
5) Velvet pouch: To store the C5, and therefore avoiding dust and scratches.
 
6) Manual:  Contains the instructions for C5 amp and warranty details. The entire manual has recently been updated to English language.
 
Overall, the packaging and accessories gives an positive first impression. Packaging is secure and practical, with accessories provided being plenty and made up of good quality.
 
 
Design and Build : The C5 has an excellent build quality and has been built with professional grade materials. Metal panels, high quality audio jacks, switches and reliable overall sturdy construction. The C5 is roughly about the size of a 5 inch touchscreen smartphone, and is convenient to attach to most of the smartphones and DAP’s making it perfectly portable.
 

 
On the top part of the amp, Volume control, LED indicator and input, output jacks are present. The volume knob is embedded inside the main body of the amp, and feels comfortable to turn. The jacks are perfectly positioned and don’t cause hindrance of space.
 
 

 
On the bottom side of the C5, an micro USB charge inlet and an charge outlet are present. An 3 LED charge indicator is present on the front-bottom side of the amp. Bass-boost and gain switches are on one side of the amp, and feel ‘solid’ and smooth to switch. The C5 includes OPA134 as Op-Amp and LME49600 as prower driver, Alps pot as volume control, among other good quality interior components. 
 
Overall the C5 has solid exterior construction, along with well designed interior circuitry, which ensures in its long life and reliable consistent performance.
 
Here is the schematic of C5 as per Cayin:
 

 
 
Specifications of C5 as per Cayin:
 
Rated output power: 800mW + 800mW (32Ω load)
SNR: ≥101dB (A-weighted)
Life time: about 12 hours (32Ω load)
Frequency response: 20Hz-100kHz (± 1dB)
Sensitivity: ≤500mV (gain H)
Charge limit voltage: 12.6V
Charging time: about 4 hours (off state, using DC5V / 2A charger)
Total Harmonic Distortion: ≤0.02% (1kHz)
Lithium battery capacity: 1000mAh / 11.1V
Size: 136x63x15mm
Weight: about 185g
 
 
 
Portability and Features : 
 
The C5 is fairly light in weight, sleek in thickness, and is well designed, with controls and switches placed at right places in right manner. It slides in easily inside an jeans pocket.and hence be considered as completely portable. It gets charged by standard 5V micro-USB cable, and that gives it an worldwide charging opportunity.
 
Headphone protection relay : The C5 employs an smart relay, which ensures one does not hear any noise or EMI apart from the music itself. The relay automatically switches on when the amp is turned on/off, and absolutely no pop/click is heard from the C5. EMI pickup is absolutely Nill.
 
Power of Zeus : The maximum output power of the C5 is 800mW@32ohms. Which is an advantage for driving full size headphones. This amount of power is more than sufficient to drive anything from IEM’s to headphones to their very loud listening levels, and the C5 does an excellent job here.
 
Smart charging indicator : An 3 LED mechanism shows the level of charge in the amplifier and the current charging status in Low-Medium-High fashion, which I find is very convenient and well implemented. The LED's blink one by one when charging and also indicating the charge level simultaneously. I should also mention that, C5 can be switched on and used during charging also, and has no audible noise even during charging.
 

 
 
Memory volume knob : The volume knob is practically designed, and the knob has a slight play in horizontal movement, which ensures, the volume does not change, if the knob is accidentally jerked or turned unintentionally. It also has numbers imprinted on it, to remember the position of the knob and level of the volume.
 

 
 
Power bank : This is an interesting yet very useful feature which Cayin has incorporated inside an portable amplifier, The C5 has an charge out port, from which one can charge DAP or smartphone. Though it is not a very strong power bank, but it can be very useful in emergencies.
 

 
 
Bass boost : This feature is found in almost every portable amplifier, in C5, the BB feature is better implemented than most of the rest. BB switch in C5 Provides an fuller pleasant sound instead of solely extending and loosening the bass quantity. The bass boost performs very well without an hitch.
 

 
 
 
 
Sound : The C5 is overall ‘clean and clear’ sounding with excellent sound stage depth ( along with very good width), imaging and detail retrieval. Considering the C5’s overall neutral sound quality, It can match up with any genre and any headphone without sounding bad in particular. C5 is not as transparent as the O2 (as a reference) but is very close in terms of sonic performance. Sound stage width is very good especially in this range, and depth is phenomenal. Detail retrieval is excellent. Imaging and dynamics live upto expectations, giving an circular spacious surround sound. C5 can overall be considered as having holographic soundstage along with incredible neutral sonic performance.
 
C5 pairs very well on an dynamic Sennheiser HD600 and Planar Magnetic Audeze LCD2. It drives both HD600 and LCD2 with authority and with plenty of power to spare. The pairing results in an pleasing and clear non-fatiguing sound to our ears. Enthusiasts who wish to drive Summit-Fi headphones on an sub 200$ portable amp, C5 is the answer.
 
 

 
Gain setting (high/Low) is very wisely implemented, with low gain specifically implemented for IEM’s and high gain for headphones. Gain setting provides more than adequate output power. An slight hiss is noticeable with IEM’s on high gain, but that can be expected as high gain would be too much and not recommended for IEM’s. Low gain is more than sufficient for IEM’s, in this state, there is no sign of hiss.  With headphones, there is absolutely no audible noise, hiss, EMI in whatsoever configuration!  
 
Impressive indeed.
 
 
Comparison with fellow amps :
 
Since Objective2 and FiiO E12 are the top contenders in 200$ category portable amps, they are chosen for comparison with C5. Lets see how they put up against each others;
 
Objective2 : The O2 wins in terms of sheer transparency. C5 is close behind on its heels. The C5’s sound stage is massive, O2 also provides a very natural and effortless soundstage. O2 ‘sounds’ transparent, whereas C5 is also transparent sounding, with being a touch ‘bright’. Though O2 definitely Lacks output power, features and portability factor of the C5.
 
FiiO E12: The E12 has upper hand in output power with 880mW@32ohms and also has an slightly better build quality than O2 and C5. But E12 is noticeably warmer and is more forward sounding than both O2 and C5, which makes the E12 to possess a narrower soundstage. It is easy to conclude that C5 is a step ahead in terms of sonic qualities when compared to E12.
 
O2 offered supreme sound quality but suffered practically. E12 was designed practically, but sound quality was forward, and hence the sound felt compromised compared to O2 and C5. I feel the C5 delivers best of both worlds, with sonic quality very similar to O2, and with features and portability similar (or even better!) to an practically designed amp like E12.
 
 
Conclusion : Cayin C5 is an truely amazing, If not an mesmerizing portable amplifier. The C5 offers phenomenal Sound quality along with excellent portability and features, in an decent price bracket. It is an easy recommendation for an portable amp. I can safely bet on C5 as the best sub-200$ portable amplifier. 
 
 
 
Not to mention, the C5 amp has won my ears.

First off I would like to thank CTC Audio for being given the chance to review this amplifier. Note, they did not give me the amp, this is a loaner program they have set up to review their product line. I am grateful for a company like them to be willing to do this. It costs them money to set this up and being a simple online retailer is a lot of work. For anyone in North America and Canada specifically CTC offers a line of some of the best Audiophile equipment that has been made in the past year at a price that is competitive while offering warranty options that are harder to get when dealing with companies over seas. I strongly recommend supporting a local company like them.
 
 
 
 
Ok stepping down from my soap box I am now ready talk about the amp .
 
Removing the amp plus it's audio cable and rubber bands from the neatly subdued packaging I was impressed with the solid feel of the amp and it's utilitarian appearance. It has a nice elegant look and feel to it. If I have any concern with the amps physical design it would be the plastic piece over the volume knob as it has cracks developed in it where the jacks plug in. It doesn't appear to be ready to break for real or anything but given that the unit is only a week and half old I would expect more durability.
 
 
 
In my case I have a very large phone so have eschewed using the rubber bands as I don't want to excerpt that much pressure on my phone or the amp. I also have paired this up with my home desktop computer and it's LittleDot DAC1, my Lenovo Laptop, and my Dell Venue 8 Pro Windows 8 tablet. Out of all my sources the amp has exhibited a consistent sound signature. I was surprised to find I actually enjoyed it most when it was paired with an already warm source such as by Dell tablet and laptop. It seemed to just flow better from those two sources. My LG G3 and my Little Dot DAC1 on the other hand lost their clarity a bit which was noticeable. But I will delve into these details later in the review.
 
Upon receiving the amp and giving it a good charge I eagerly plugged it into my LG G3 phone and prepared for some MAGIC! Sadly I was quite underwhelmed... Instead of a big sound and added detail I was presented with a warm sound that was lacking in detail and dynamics. Needless to say my first thought was DAMN AM I GLAD I HAVEN'T BOUGHT THIS! So I immediately posted my initial impressions and was quickly reassured I should let them burn in for a day or two. Now this is tricky as I only have a week to test this gear. But I was determined to give this amp the attention it deserved so I dutifully plugged it in and set it to playing music with one of my headphones and left it. The next day I recharged the battery and tried the amp again. This time I was pleasantly surprised. The warm thick sound was reduced dramatically and upper details were suddenly present. So I dutifully left it running for another day. Upon the next listen the sound had changed yet again and I started to notice more subtle changes in the overall sound of my headphones. The difference was most noticeable with IEM's followed by closed headphones. There was a decided added level of 3D space and presentation. I will be honest, I never expected it to really exist even though I had read about it in the forums. I simply couldn't believe that an amp would have that impact on the way a headphone would sound.
 
One thing I have experienced with amps is hiss and possible electric noise from other sources. Fortunately the C5 had NONE of these issues. I did not get any noise from my phone and the amp had pretty much no hissing with any of my IEM's or headphones. For me THIS IS ONE OF THE MOST IMPORTANT ASPECTS OF AN AMP.
 
So I started to do a round of A/B testing primarily from my LG G3. My testing was to set the amp to be at the same volume level as my phone so I could simply switch back and forth between my the phone directly and the amp. I used a variety of different songs and tested the amp with about 8 different headphones and IEM's. Below is each headphone listed wit the general experience I noticed.
 
T-PEOS Altone200 - This IEM is one that has me definitely on the fence. After reviewing several warmer IEM/Headphones I have been turned off of sharp treble and the Altone200 is definitely sharp!. The C5 took this IEM and tamed it's highs just enough to give me an added level of enjoyment. The bass button also helped to warm up the sound. The IEM by nature has a TON of detail so the little bit lost by the amp was noticeable but not seriously missed. Out of the IEM's tested this one benefited a lot from the amp. The C5 also took an already expansive sounding IEM and made it sound even bigger and more 3D like.
 
RHA T10i - This IEM has been designed to work best directly from devices like my phone. In my time with the IEM most amps have exaggerated it's bass which hinders it's presentation. The C5 did this badly in the beginning but after it was burned in actually started to sound better. While it still amplified the bass it managed to also help bring out the treble of the T10i a bit and added to the already decent sized sound stage. Out of the IEM's tested this one benefitted the least from the C5 but I did start to enjoy the changes it brought to the table.
 
Pioneer DJE1500 - This IEM is my current favourite as it offers an excellent level of bass punch while still offering a full mid-range and treble. The C5 elevated all areas of the IEM and smoothed out a bit of it's harshness in it's upper midrange and lower treble. It also added some wonderful spatial queues to the IEM already impressive sound stage. The bass button was also nice as it added some warmth to the IEM which was helpful with some of the music I listen to.
 
Vivo XE800 - This IEM is a boil-cellulose variant of the GR07 made specifically for Vivo. It's signature by nature is balanced and very clean with almost BA like levels of detail. The C5 consequently had a small drop in the level detail and a slightly smoother sound. But like the DJE1500 there was less harshness in the upper midrange helping to ensure no sibilance from the IEM. There was also added level of 3D spatial qualities which helped add some height to the slightly 2D sound stage of this IEM. Again the bass button offered a nice added touch of warmth and bass presence to this IEM.
 
Etymotic H5 - The Etymotic H5 is a very special BA in my books as it offers excellent detail and neutrality. The C5 simply took that sound and smoothed it out a bit and offered added bass punch and warmth when used with the bass button which made the H5 sound much more enjoyable especially for male singers. I feel the bass button might be enough reason to get this amp for anyone who loves their H5 but wished it has that added warmth. The C5 also helped increase the 3D spatial qualities of the H5 a lot. I would say it's a toss up between the H5 and the Altone200 as to which benefited the most from the amp.
 
Sony MDR10R - This headphone is by design a bit on the warm side so the C5 just takes that area to the next level. The headphone is also a bit power hungry so really benefited from the added juice of the amp. I was able to comfortably use the low gain setting while still gaining added volume and clarity. The C5 also helped take a decent sound stage and make it even bigger and more 3D like. These two played very well together but only if you enjoy the general signature of the headphone as the C5 just accents that signature further. The bass button was to much for this headphone in my opinion.
 
Sony MDRZ7 - I only have had this headphone for a short while so will add impressions after I have had a chance to let the headphone burn in.
 
AKG K712 - The K712 is the only headphone in my testing that struggled to gain a benefit from the C5. It was only barely louder on low gain and had a harsh tone to it when using the high gain. I suspect it simply falls into a gap between the high and low gain settings. It is also those the most competent headphone I have in regards to sound stage and spatial abilities so doesn't really gain anything from the amp in this regard. But the bass button on the amp definitely helped warm up the signature of the headphone which was nice for male vocals.
 
As I mentioned I did use the amp with various other sources. I was surprised to find it seemed to work best with warmer sources enhancing their signature versus colder sources where is simply diminished their good qualities.
 
Over all I think this amp deserves a 4.5 out of 5 for it's sonic qualities. It worked very well with most of my sources with no noise issues. While it slightly alters the sound it does so in a generally pleasing way especially in regards to the sound stage. My only concern would be the plastic piece with the volume knob in regards to physical build quality dropping the score in that area down to 4/5.
 
So if your in the market for a portable headphone amp I don't think you can really go wrong with the Cayin C5. It offers an excellent price/performance value and offers enough battery life to give a person a typical full day of use.
 
Tech Specs:
Rated Output: 800mW + 800mW (32Ω load)
SNR: ≥101dB (A-weighted)
Battery Life: Up to 12 hours
Charging Time: ~4 hours
Frequency Response: 20Hz-100kHz (± 1dB)
Sensitivity: ≤500mV (Hi-Gain)
Total Harmonic Distortion: ≤0.02% (1kHz)
Lithium-Ion Battery Capacity: 1000mAh / 11.1V
Dimensions: 136 x 63 x 15mm
Weight: ~185g / 6oz.

I'll refrain from writing an extensive review this time, as everything important has already been shown and written down in the other reviews here on head-fi. I second those opinions and can recommend the Cayin C5 as a partner for the Fiio X5, as It beats the X5's internal amp in all the areas that are important to me. It's a very nice combination, in some ways even on par with the Stax setup (Stax Lambda Signature with modified SRM-T1) I owned in the past.
5 stars.

First of all, I'd like to thank Cayin for opportunity to review C5. As usual, main review is in Russian, here I'll share mt impressions in brief.


There is not so many good portable amps in sub $200 range. It's almost completely dominated by Fiio E12, which is really good. Now, Fiio have really strong competitor.

Cayin have lots of experience in "serious HiFi", their amps, both tube and solid-state, CD transports, speakers, etc. — well known allover the world. So, their debut on portable HiFi market was really impressive.

First thing, you're noticing is design. C5 is somewhat vintage-looking, it reminds classic devices of early 90: "champagne gold" body, plastic parts, orange leds, really nice. But, of course, not for everyone. You like it, or you hate it (in terms of design, of course). Build quality is good. First revision had some problems with plastic, but Cayin fixed this quickly.

Controls are as simple, as they can be for portable amps. On top — two sockets, for input and for output and volume pot, combined with power switch. On bottom — two micro USBs, one for charging C5, other for charging something else, using C5. Ability to use your portable amp as powerbank can be sometimes useful, but with 1000 mA/h battery you won't be able to use it frequently, so consider it as "emergency" option.
On one side you'll find gain and bass boost switch. That's all for controls.

Battery life is about 12 hours. I definitely Ok with that, but, as usual, more will be better.

Sound-wise, C5 is really nice. It offers interesting sound with wide and deep soundstage. Great instrument separation and localisation with appropriate headphones will give you "3D" sounding, really nice on live records, big orchestras and other music, requiring nice staging.

Bass is good. Impactful, nicely controlled, but not overwhelming and leaking to other frequencies. Bass boost is pretty delicate: it's adding body to music, but not that "crash your ears bass". Mids are lively, clear and detailed. All emotions delivered as is in record. Highs are a little bit roll-off, so they are not fatiguing or sibilant.

Compared to E12, C5 sounds little bit "muddy" (a tiny bit) at first, but then I've found that C5 sound is more enjoyable for me, it has more body and sounds "more musical".

Power-wise C5 is really good. It has enough power to drive high-impedance dynamic headphones with ease, and even some planars are OK with C5 too. From other side, sensitive IEMs are also enjoyable, I've experienced no noise on low gain.

Generally, Cayin C5 is really nice competitor at it's price range. Unusual design, great sound, affordable price — it has it all.

This is a review of the Cayin C5 portable amplifier.
 
The specs:
Rated output power: 800mW + 800mW (32Ω load)
SNR: ≥101dB (A-weighted)
Life time: about 12 hours (32Ω load)
Frequency response: 20Hz-100kHz (± 1dB)
Sensitivity: ≤500mV (gain H)
Charge limit voltage: 12.6V
Charging time: about 4 hours (off state, the use of DC5V / 2A charger)
Total Harmonic Distortion: ≤0.02% (1kHz)
Lithium battery capacity: 1000mAh / 11.1V
Size: 136x63x15mm
Weight: about 185g
 
Built and accessories:
The built of this unit feels very solid. I've used mine heavily for about six weeks now without any problems. I also love it's retro design and champagne colour:
 

 

 

 

 
It arrived in a nice paperbrown cardboard box which also felt a bit retro to me:
 

 

 
Included accessories are two blue rubberband for pairing with a DAP or phone, a short 3,5 mm to 3,5 mm cable for hook up and a mini USB to mini USB cable to use when charging other devices from the C5. Yes, it can also double as a powerbank. The battery capacity is limited to 1,000 mAh though so I've only tested that this feature works but not used it other than that. Altough I've never clocked it I's estimate the battery life on the C5 to be about 8-10 hours depending the headphones/Iem's you use it with. There's also a led indicator with three levels which shows when battery starts to lose power. The C5 also has a gain switch which allows you to choose between "high" or "low" gain as well as a switch for bass boost. I find the bass boost to pretty good and instead of adding a lot of ekstra bass it rather gives a slightly fuller sound. A charging cable for the C5 would have been nice to have included as well. 
 
The accessory pack:
 

 
Sound:
I've used the C5 in a number of configurations such as paired with my HTC One M7 phone, FiiO X3, Ipod Touch 3G and from my computer fed by the Geek Out720 or Audioquest Dragonfly. I've also used it with mulitple headphones and IEM's. While using it with my phone I could not detect any interference from the phone on the C5 at all.
 
For this review I've used the configuration with my computer to the GO720 feeding the C5:
 

 
The headphones I've used are the Beyerdynamic DT880/600ohm, AKG Q701 and my modded Fostex T50RP's:
 

 
The IEM's used during this review are the Havi B3 Pro1 and the Vsonic VSD3S:
 

 
 
Set to low gain the C5 is dead silent even on max volume with the very easy to drive VSD3S. On high gain I can clearely hear a hiss with the VSD3S but not with any of the other headphones used in the review.
 
I would describe the sound of the C5 as very fluent and I'm also strucked over and over agin by how clean and clear it sounds. I find it to be great for long litenening sessions and it never feels fatiguing in any of the configurations I use it in.
 
I think it's very difficult to describe the sound from an amp (much more so than with heaphones and IEM's) so I'd rather compare it with a couple of other well regarded amps and describe the differences.
 
Comparison:
I've compared the C5 with the FiiO E12 and the Light Harmonic Geek Out720.
 
The line up:
 

 
Cayin C5 ($169) vs FiiO E12 ($88):
Both of these amps packs enough power to drive every headphone I own. I've been using the E12 a lot since I got it about 5 months ago. I've been very pleased with the E12 for the time I've used it. I only paid $88 for it shipped, brand new so I still consider it a great value. The two main differences between the two (and these differences are very easy to hear) is that the E12 is warmer and has more background noice (hiss). This is naturally worst with the VSD3S and is clearly audioble also on low gain. This has never bothered me before but in comparsion with the C5 it's very obvious. The warmer sound of the E12 makes it feel a tad less clear and neutral. While I wouldn't ever call the C5 a bright amp it is still slightly brighter than the E12 and it feels more distinct in what it does. This gives a feeling of better separation on the C5. The C5 also has a fantastic timber to every note that I'm missing on the E12. Although rated with a similar power output the C5 gives a little higher volume with the volume knob turned to the same level on the both. I guess this would mean that the gain is a bit higher on the C5 or that one of the specs are slightly wrong. The sound differences are by no means huge but it's clearly there. It's aslo obvious the the E12 was made to drive full size headphones and not easy to drive IEM's and although it does that very well (especially for a portable amp) the versatility on the C5 is better since it will work equally good with any IEM/headphone.
 
Cayin C5 ($169) vs Geek Out720 ($169):
The C5 has a higher rated power output compared to the GO720 and that's pretty obvioys with the DT880/600ohm were I need to max out the volume with the GO for some music and in some cases (recordings with low sound level) even that is not enough. I've been using the GO720 heavily since I've got it about one month ago. The GO720 also introduce a slight hiss with the VSD3S but not with any of the other headphones I've used here. I'd say that the difference between the C5 and the GO720 is way smaller that that between the C5 and the E12 (especially after the lates fw update on the GO720). Still I'd say that the C5 is a bit cleaner sounding while the GO is very slightly warmer. The difference between these two might very well be more preference than difference in actual quality since separation and details sounds equally great on both. I aslo actually feel as if the 47 ohm output on the GO720 saounds a bit cleaner than the 0,47 ohm one with all the headphones/IEM's I've tried it with bringing it even closer to the C5. The full sized headphones I've used here actually sounds pretty much identical from the 47 ohm output and the C5 which shows that the C5 stys very true to it's source. Given the fact that the GO720 is also an outstanding DAC it's certainly a device with great value, on the other hand the C5 has that extra power for those who need it and can slo be connected to other sources with a simple 3,5 mm cable.
 
Summary:
The Cayin C5 is without doubt the best amp I've ever owned. The fact that it comes in a truly portable form factor and has the power to drive every headhone that I own as well as great performance with all of my easy to drive IEM's makes it a great versatile unit that's very easy to recommend to others.
 

This is a review of Cayin C5 portable hi-fi headphone amplifier. http://www.shenzhenaudio.com/cayin-spark-c5-stylish-portable-hifi-audio-headphone-amplifier-2014-new.html
 
As I mentioned in one of my recent reviews, headphone amplifiers opened up to me a new world of sound shaping. Though I don't have any power hungry or high impedance headphones, I was in for quite a surprise with a number of my IEMs and how much sound improvement you can get from a well designed portable amp used either with your smartphone or digital audio player (DAP). Unfortunately, with a few amp models that I tested, the results were better when driven from Line Out (LO) versus Headphone Output (HO) where bypassing internal output amp played a better role in synergy with an external amp. All good if you have an advance DAP with LO, but a lot of us still using smartphone or common mp3 players (like Clip+) to play a music. Without expecting too much, I got a hold of Cayin C5 review sample and so glad that I did!!! Here is what I found.
 
Arrived in a very sturdy and eco-friendly box, it was packaged quite well and secure. Inside you will find C5 headphone amp, instruction manual (all in Chinese), two rubber bands (for attachment to your phone or DAP), 4 sticky rubber bumps (to use as mounting legs), a draw string storage pouch, a short 3.5mm to 3.5mm audio cable jumper, and micro-USB to micro-USB short cable (since you can use this amp as an external battery for your smartphone). I have been told that Cayin team is working on updated instruction manual with additional English text, though I didn't find it as a showstopper to start using and enjoying this little gem.
 
Starting with a design, I found it to have an overall shape resembling E18, though C5 was a little bit longer. Unlike a lot of other portable amps/dacs that come in black color, this one stands out with a very unique blend of gold/silver finish. The body of this amp is solid metal, very well build, and absolutely no panel flex. At the bottom you have a thicker plastic cover with 2 screws and a pair of micro-USB ports, one labeled as PWR IN (to charge the amp) and the other one as CHG OUT (as external battery to charge your smartphone or a tablet at 1A output). At the lower bottom edge you also have 3-led battery indicator, and on the opposite side - a reset pinhole. On a right side closer to the top, there are two triangular shaped slide switches for Gain (high and low), and Bass (on and off). At the top you have a volume potentiometer (Japanese made ALPS) which also turns the unit on, and 3.5mm Line In and Headphone Out ports. The top of the amp has a semi-transparent black plastic cover which can be removed. I found it to add an interesting touch to the design, just not sure how durable it's going to be if you drop this amp on the ground.
 
The spec of this amp is very impressive with a selection of top rated components including highly regarded Burr-Brown SoundPlus high performance OPA134 opamp from TI, output power rated at 800mW + 800mW (w/32 ohm load), 1000 mAh battery (at 11.1V) with a running time of about 10-12hrs, super low distortion, high signal-to-noise ratio, and so on. For some it will mean a lot, but the main question is how does it translates into a real world sound test, especially driven from HO?
 
In my test I used Galaxy Note 2 with ATH-IM03 IEMs. With headphones connected directly to HO of the phone, you get a congested sound with mediocre clarity/details and average soundstage. Using E18 as amplifier, you get a marginal improvement with sound still being a bit darker and not as detailed, and not much of soundstage improvement. Kicking it up a notch with E11k, it brightens the sound in comparison to E18 amp, and you starting to hear more details with a perception of a wider soundstage. But once you switch to C5 - BAM!!! you just can't believe your ears how clear and detailed sound gets with a new additional texture and previously missed sound layering, a bass that comes alive, and MASSIVE 3D soundstage. I have a guilty pleasure of watching movies on my Note 2, and adding C5 turned my phone into a mini-theater experience. Since I'm planning to upgrade to Note 4, perhaps adding Gear VR and C5 will turn it into 3D Theater Experience!
 
Running the same comparison test from HO of my Thinkpad laptop also showed a drastic improvement in sound quality. My laptop HO output is even worth than my smartphone, that's why I always use it with E10k. Here with C5 it added more details and wider soundstage even in comparison to E10k, though you would probably want to keep C5 charging from USB port of laptop while using it this way. Btw, the same with a smartphone. Though it will cut down on battery life of C5 using it as an amp and external phone charger, you will not drain your smartphone battery as much. Furthermore, running a similar test from LO of my X5 yielded the same consistent results between E18, E11k, and C5 where sound quality and soundstage had a noticeable improvement.
 
Overall, I found Cayin C5 amp to have quite a remarkable performance considering being able to take a lo-fi HO output and to make it shine! It might not be as versatile as some other Amp/Dac units where you can connect it through OTG USB or USB to your laptop to use as external sound card. Also, it doesn't have as spectacular battery endurance since it uses power hungry components and design architecture. But it makes up for all of these shortcomings with an amazing sound improvement that you gotta hear it to believe it. For under $160 some might consider it a bit pricey since it's still a one trick pony, but it does that one trick like a First Class Magician!!!
 
Here are the pictures.
 
The unboxing.
 

 

 

 

 

 

 

 

 

 
Design details.
 

 

 

 

 

 

 

 

 

 
Paired up with my Note 2
 

 

 

 

 
Next to other DAPs.
 

 

 

 
Side by side with E18.
 

 

I remember browsing the ebay like many of you guys do to see what is out there in portable amplifier land and this one caught my attention because for one it looked very nice and second it posted some specs that also caught my attention. Now that I have had this for 4 weeks of constant use I figured it was about time I let the community know how this portable amplifier fares.
 
SPECS:
Cayin C5 Stylish Portable HIFI Audio Headphone Amplifier
Technical characteristics:
1 dedicated high-performance audio op amp OPA134 and LME49600 buffer composed of dedicated headphone amplifier, low noise, driving strong.
2 Japanese original ALPS volume potentiometer, durable and reliable, to ensure quality.
3 built-perfect protection circuit, with the midpoint of drift, switch machine noise cancellation function, the output using relay protection,full protection of the amplifier and headphones.
4 can be used as a mobile power source to charge other mobile devices.
5 aluminum shell, effectively shielding interference.
6. subjective listening experience
 
Technical Parameters:
Rated output power: 800mW + 800mW (32Ω load)
SNR: ≥101dB (A-weighted)
Life time: about 12 hours (32Ω load)
Frequency response: 20Hz-100kHz (± 1dB)
Sensitivity: ≤500mV (gain H)
Charge limit voltage: 12.6V
Charging time: about 4 hours (off state, the use of DC5V / 2A charger)
Total Harmonic Distortion: ≤0.02% (1kHz)
Lithium battery capacity: 1000mAh / 11.1V
Size: 136x63x15mm
Weight: about 185g
 
American TI company specializing in Hi-Fi Headphone Power Driver IC
German company's top Hi-Fi WIMA capacitors
Japan's top ALPS Hi-Fi level potentiometer
Japan's Fujitsu's top-level Hi-Fi relay
 
BUILD:
 
The amp in person is very nice looking with it's golden colored aluminum and cream colored plastic on the top and bottom. It kinda has a retro look to it and definitely stands out among portable amplifiers in looks however the build is just average on the C5. My biggest problem is the top portion of the amp which has a black plastic covering that covers the volume dial, input and output jacks. I discovered early on that the plastic was too thick for the jacks therefore was cutting out my music. I do think this is more of an isolated case but there is some potential for issues. Cayin folk seem to have fixed this particular problem and they were nice enough to offer a replacement for my C5. Which I gladly took advantage of. Currently waiting on the replacement. I first tried to fix the issue by making larger cut outs where the input and output jacks are but I am still having the same issues.So I now use the amp without the flimsy black covering on top. I seem to have less cut out issues while it still occurs on occasion so I am looking forward to the replacement of this unit. But problems aside it is the ability and the sound of the amp that has gotten my attention.

 
SOUND:
 
I was immediately impressed on open listen of the C5. This is what I wrote on open listen.
 
Aha guys..I don't need to compare this amp to my 2Stepdance or my ICAN...I am using my L2 for my initial listen.. This thing sounds unbelievable..One of the best sounding amps out of the box I have ever heard. This thing sounds better than the way it looks. The stereo field is layered beyond normal amplification to the point where it is holographic..Sound stage is already impressive out of my L2 but using this amp. Music is coming at me from all direction very similar to how the 3D enhance feature works on the ICAN. But the crazy thing is the C5 don't have this enhance feature. Very natural..It is not a sterile neutral type sound but much more musical and fluid sounding amp. More organic than clinical..The lushness of vocals and crispness of instruments simply sound stupendous, world class .This is easily on par with my ICAN. I think the bass could be slightly better. And this is without the bass boost.. Bass boost adds fullness to the lower end but is done tastefully here. No overblown mess. Without it the bass is reference sounding. No bass boost needed. Power for days. I am just using low gain with so much power room on tap. It is going to be interesting to see what cans this thing drives as it can reach blaring volumes on the quick.. I will have more to write when I get some hours on this amp but I can safely say. This amp is more than worth the money spent on it.  HIGHLY RECOMMENDED..I can see this amp quickly becoming very popular around here..Can't wait to put some time on this amp.
 
The sound is decidedly mature, grand in scale, smoothness showered with clean detail.  The sound is expanded in height, width, depth..If your waiting for me to say this amp sucks..Nope..What I am going to say is. This is one of the best sounding amps I have ever heard..Will give your expensive desktop amp a run for sounds and probably has more power. Lol. I thought my ICAN was the best amp purchase of this year I have made. I have to rethink this.
 
AFTER BURN IN/ MORE USE

 
The sound of the unit has refined even more so. While the underlying musicality of the amplifier is still very present the sound has tightened up overall and now has a much more transparent quality to the sound. In comparison to open listen the bass has settled and tightened. This had a very positive effect on the bass boost which is around 4-5dbs of bass which is very welcomed when using more neutral signature phones like the Zero Audio Doppios..
 
NOISE / BASS BOOST:
 
My Doppios are a 12 Ohm sensitive dual BA iem that has one of the best neutral signatures for any phone I own. The noise floor is very quiet, if not dead silent using the Doppios. I like using the Doppios to test out a signature of an amp or it's bass boost. To me with the addition of bass boost, the added dbs of bass makes the Doppios sound world class in refinement, more fuller sounding, while not loosing a single sliver of detail of the music. This clearly shows that bass boost was done tastefully here and actually adds to the enjoyment level of the Doppios on the amp.. Using something like the XBA-H3 or FX850 which already has a healthy dose of bass as a part of their sound make up need no bass boost at all but it is good to know that the bass boost is actually useful for earphones that can use a bit of boost down low. It adds to the fullness of the sound as well as the low end and sounds very natural and not overly cooked. Bass boost is done well here. Adding bass boost to the H3 brings the sub bass to semi bass head levels which is a blast for hip hop and edm.
 
I have used the C5 using a variety of cans and earphones. The Shure SRH1540, Philips Fidelio L2, Fidelio X1, ATH AD900X, Sennheiser HD595, ATH-CKR10, ATH-CKR9, JVC FX850, Nuforce Primo 8, ZA singolos, Doppios to name a few and all of them work exceedingly well with this amp. All on low gain. High gain is reserved for more power hungry cans which I own none of.
 
AMP COMPARISONS:
 
Vs ICAN Micro, I touched on a few comparisons on the initial thoughts but with some head to head comparisons the C5 has clearly shown me that it is punching above the price payed for the amp. On open listen I thought it had more than a few similarities to my Micro ICAN. The way the amp portrays stage in particular is very similar..The ICAN is a higher end desktop amp that has gotten plenty of attention on headfi and is my reference amp for all things amping. While not the very best amp in the world it is to me a very high end sounding amplifier and does have a reference clean large layered sound with plenty of power on tap. I went into the C5 purchase thinking there will be no way the C5 will be like my ICAN. I was floored when I first heard the C5 because it did in deed remind me of the feeling I get when I listen to the ICAN. On head to head listen the ICAN does have a bit more transparency and has the edge when it comes to clarity and refinement but the C5 is very close. The C5 does have a bit more bass emphasis while the ICAN is more linear in the bass region making it sound a touch more neutral in presentation. The way the ICAN and the C5 project sound in all direction is what I find the most similar. Sound separation in the sound field is another aspect that is of similar quality. I was all too happy to hear how high end the C5 was in comparison to my ICAN. Sure the ICAN is still my best amp but it is how close the C5 comes to it that I am over joyed about. This ability on the go? Are you kidding? Not to mention it has the power to drive just about any can or earphone with clean power.
 
Vs 2Stepdance..This was my first portable amp that truly brought high end fidelity to my portable sources. My good buddy DannyBai sold this to me a while ago and I always have a feeling like he regretted selling it to me. In any case long story short I wanted to eventually help find an amp to replace his 2Stepdance that he sold to me and I can say without a doubt the C5 did this nicely. The 2Stepdance is an impressive amp because of not only it's sound fidelity but also due to its clean wide open type nature of sound. It has the widest stage of any amp I own. The sound separation is something wicked with this amp. Compared to the C5 the staging is a bit wider on the 2Stepdance but sounds thinner in the mids. These amps are in many ways similar to the nature of closed, semi open and open cans. I would say the 2Stepdance is more like an open can in that it just spreads out the sounds. Classical, instrumental, Jazz will all benefit from such an amp because of how it lends to the type of music. The C5 in comparison is like a semi open Can. It has the ability to have an equal sense of stage but also has a more fuller thicker sound to it.. The 2Stepdance sounds like your hearing music on the first balcony a wide picture of your music.. The C5 is more like the front row..Mids I find the most different in presentation. The notes in the C5 are fuller and encompass a more in your face type sound than a "step" back from the music presentation of the 2Stepdance. The difference in sound presentation is different from each other yet both are very enjoyable depending how you like your music. Instrumentals and big bands on the 2Stepdance is ideal while music with vocals, ambient and more aggressive music in nature like rock metal, edm will certainly love the C5 more so.
I find the ICAN being in the middle of these 2 presentations. The C5 is more musical, fuller sounding while the 2Stepdance is more precision driven that leans more on stage and sound separation.
 
Vs NFB-5 For guys that own any of the specialized OPAs configurations of the NFB amp dacs. I can confirm my C5 is more like the MOON OPA that is an option for many of their amp dacs..The C5 sounds more like the MOON opa in many ways. Fuller more immersive note with a full bass end that makes the MOON OPA a favorite among enthusiasts. The C5 is like a portable MOON OPA on roids. The C5 is not a clinical sounding amp but has the technicality,power and ability  with the right source and headphone combination to absolutely sound stunning. The nature of the sound is based on immersion because of it's bold full sound. The amp section of my NFB-5 using the MOON Opa gives a romantic type sound presentation and I suppose the C5 can be that way with your music. The C5 has greater stage presence than the amp portion of the NFB-5 and that was a big surprise to me. Both are identical in how it presents the sound but with it's larger more spacious sound the C5 was a pleasant surprise here.
 
VERDICT:
 
While the build could be better and the battery life longer as it lasts in real world test more closer to 10 hours vs the 12 that was stated on the description. I am willing to overlook the minor flaws of the amp simply because the amp delivers where it counts for an AMP. The sound. The fidelity of the amp is very close to the best amps I own and can more than hold it's own against my best amp in the ICAN. It can drive just about any phone you own with more than enough power on the go. It can charge your Iphone or smartphone too but haven't tried this feature. It has a sound that is extremely enjoyable and versatile. For the money payed. Yes it gets a hearty thumbs up from me. I have it attached to my DX90 almost all the time now a days as the player by itself is no push over but with the amp it takes the clean dual sabre dac chips on the DX90 to a new level. A sign of a good amp. I am very encouraged with the Cayin C5 and very much recommend the amp for guys that want to take their sources with the added bliss of true high fidelity added with a stupid amount of power on the go. This sound is a marvel and the cost is very aggressive for the level of sonics. Very nice product Cayin. Now try n fix the minor flaws for the next one and you will have a fan for life. Thanks for reading and as always happy listening.