Portable Headphone Amplifier Review
There has been a rise in interest in hi-fi headphones and even headphone amps on Overclock.net recently due largely to posts by myself and a couple other amateur audiophiles. While I may be one of the more knowledgeable members of OCN I do not consider myself a full fledged audiophile, and I must admit that I still have a lot to learn and have yet to really train my ears as well as I would like. But nonetheless my pursuit of audio nirvana continues. This review in essence is just one glimpse at my own journey along this path, and what sounds good to my ears may not necessarily sound good to others, so these are merely my opinions and should be treated as such.
The goal of this test was to look at several portable headphone amps that do not break the bank. As such the most expensive amp I looked at costs a very reasonable $110. The cheapest can be found used for as little as $45, but sells new for about $70. I have used all 4 amps reviewed today with my portable setup and they all perform well there, however for the review I used a home setup to give them the best signal possible and to keep listening conditions as close as possible. I do not have any way to keep the volume static, but I did my best to keep it constant and at a comfortable listening level.
Amps Reviewed:
Little Dot Micro+ Company Info;
Ordering Info
Xtra X-1 Ordering Info
C&C Box v2 US Distributor Info (There are 2 US distributors and I purchased my amp from the other distributor, Soundwise on head-fi)
Mister X XP
Pocket Amp 2 Version 2 Ordering & Product Info
Test Setup :
Transport : Philips DVP-642
DAC : Upgraded Zhaolu 1.3
Interconnects : Blue Jeans Cable digital coax & Soloz Audio silver RCA-mini
Sennheiser HD580 heaphones with HD600 grills & HD650 cable
Test Albums :
Erich Kunzel and the Cincinnati Symphony Orchestra: Tchaikovsky’s 1812 Overture
Amazon
Track 1:
Tchaikovksy’s 1812 Overture is one of my favorite classical pieces. It starts out smooth and detailed and erupts into an explosion of energy at the end. It is simply an exciting piece of music to listen to. This particular recording is quite detailed and interesting as it utilizes real cannons and bells near the end of the recording. This is probably the most energetic and fun to listen to recording of the 1812 Overture I have come across.
Massive Attack: Mezzanine
Amazon
Track 7: Man Next Door
Massive Attack is a group that I have only recently discovered. They show influences of jazz, hip hop, reggae, rock, electronica, and even classical. This is a very interesting disc to listen to and is also good for testing audio equipment.
Man Next Door has deep synthesizer bass, smooth vocals and is a great track to distinguish stereo separation.
Staind: Chapter V
Amazon
Track 2: Right Here
This CD is probably the most well known disc chosen for this review. I have been a long time Staind fan and Right Here, while not one of their most popular songs is one of my favorite. The guitars are grungy and the drums tight. Cymbals are also strong and can easily be fatiguing if the source or amp are too bright.
The Amps:
LDM+
Cost: $71
Op-amp: MAXIM MAX9724
Battery Life: 100+ hours
The LDM+ is housed in a small metal case which is pretty durable. It comes in either Silver, Gold or Black and is bundled with a mini-mini IC and a power pack. The amp itself is rather handsome and resistant to scratches. I am the second owner of this amp and I have had it for about 8 months so it has seen many, many hours of use. The best feature of this amp is the battery life, which is simply amazing to say the least. Battery life easily tops well over 100 hours. I have charged my LDM+ probably no more then 3 times since getting it. Build quality is about a B. It is durable, but not the prettiest amp of the group under review. The mini-mini IC that was included is lacking. It was far too long to be used for portable use and was not high quality. I have heard that an upgraded 6” mini-mini IC is now included. The LDM+ does have a faint turn on thump.
Sound:
The LDM+ is a great little amp. It is probably the most neutral amp in its price range <$75 including shipping. However, it is not the best sounding amp reviewed today.
Tchaikovsky
The LDM+ had only mediocre performance with this recording. There was good bass extension, but it was not well defined. Some of the instruments seemed to blend together more then they should at times. The highs were a bit tinny. Overall the mids are the strong point with this amp. Overall the LDM+ was just a bit shy on dynamics to make this piece truly exciting. The cannons and bells were a little dull.
Massive Attack
The LDM+ does a pretty decent job with this track. Bass is strong, but not very tight, neither is it bloated though. The vocals are a bit grainy, but not bad at all. The big disappointment here is in the stereo separation. This track makes ample use of both channels and often plays different instruments through each channel or sweeps back and forth. The LDM+ was by far the worst amp in this review here. It was almost as if the LDM+ had some crossfeed enabled, which it does not.
Staind
The LDM+ did a great job with the bass on this track, but the cymbals were a bit shrill and fatiguing. The vocals were not as clear as some of the other offerings.
Xtra X-1
Cost: $93 plus AC adapter
OP-amp: OPA2134
Battery Life: 20 hours
The X-1 is probably the smallest amp reviewed and it came in the most attractive packaging. Color options include the standard Black and Silver, but it is also available in Blue. Included accessories: mini-mini IC, wallwart, pouch to carry the amp and protect it, & box. One important thing to note is that the wallwart has the European style plug so you will need to get an adapter to plug it into a standard US AC outlet. These can be purchased from Radio Shack for around $10. The mini-mini IC is better then the one supplied with the LDM+ and the included pouch is very nice. I wish the LDM+ came with a carrying pouch. The faceplate of this amp is different from all the others in that the volume pot is located in the middle, in between the input and output jacks. This can make it difficult to change the volume if large plugs like the Canare F12 are used. The power switch is not built into the volume pot but instead there is a small button to turn the amp on and off. The only problem is that it is located on the back plate of the amp. If you plan to carry the amp in a case like I do then this means you have to physically take the amp out to turn it on and off. I am the second owner of this amp, but combined usage between both users is around 100 hours so it was well burned in before review.
Sound:
The Xtra X-1 is a fun little amp. Of the group it is probably the least neutral, but it adds a punch that makes this amp very fun to listen to. Being the second cheapest amp reviewed it is still a good value for your money, but if you plan to use the amp for critical listening then you should look elsewhere. If you want a punchy, amp to enjoy your music on the go then this just might be the amp for you.
Tchaikovsky
You can defiantly tell that this amp has a bit more slam then the LDM+. Bass seems to be a bit rolled off, but you can definitely tell it is still there. This may be due to what would appear to be a slight boost in the frequencies around 100Hz. This gives the upper bass a lot of slam. The highs are not as tinny as on the LDM+, but they are far from smooth and silky and I would still consider them shrill. The amp does not handle great separation and some of the instruments again seem to get lost amongst one another. Overall a fun experience with the cannons even though the bells seem to be lost at times. Not a very critical amp.
Massive Attack
Here the huge synthesizer bass seems bloated and grainy. Stereo separation and definition seem to be lost as well. Once more this amp makes for a fun listening experience but is not detailed at all.
Staind
Once again this is a bassy amp. Bass and lower mids emphasized leaving the upper mids almost undistinguishable. Highs are tinny.
C&C Box v2
Price: $112
OP-amp: AD8532
Battery Life: up to 70 hours, but 30-40 is more likely
The C&C Box v2 is a relative new amp that has only recently made a splash in the US. There are currently only two North American distributors. I purchased mine from a group-buy on head-fi at a slightly reduced rate. Physically the case used for the C&C Box is almost identical to the LDM+ only longer. Also, the paint used is different. While the LDM+ has a flat black, the C&C Box is glossy. Overall it is a very attractive looking amp. The C&C Box comes packaged with a wallwart, mini-mini IC, carrying pouch, and a certificate of manufacture.
One thing that quickly sets the C&C Box apart from the other amps reviewed is that there are 3 switches located on the back panel along with the power jack. These are labeled as: MF, LF, & SF. According to the distributors MF is for vocal enhancement, LF is bass extension and SF expands the sound stage. All 3 switches have 2 positions off and on and you can use any combination to suit your liking. Personally the only switch I feel makes any good improvement is the one corresponding to sound stage expansion.
I should add that one of the distributors has packaged the box in a very attractive box while the other has not. My amp came with slight imperfections to the paint on the back plate and in no way affect the sound, but being the perfectionist I am I contacted the distributor about this issue.
Sound:
Overall this is a very nice sounding amp that shows potential for greatness. I have used this amp quite a bit in my portable rig and have been impressed and greatly enjoyed what I heard. As previously stated the SF switch does appear to give the music more dynamics and an enhanced sound field.
Sadly, I was not able to perform the same listening with the C&C Box as I was with the other 3 amps reviewed today as the amp simply could not handle even the low level line output on my Zhaolu DAC. The amp was driven to clipping and resulted in crackles every time the bass hit. The 1812 Overture was the only test track that was listenable and then only before the cannons kicked in. But during the brief time spent here are my thoughts.
The C&C Box is very pleasant to listen to, but has a loud turn on thump so it might be a good idea to turn the amp on and then plug your headphones in. It is not quite as detailed as the XP and it does not have the slam of the X-1. But it is a fairly detailed amp nonetheless.
I have talked extensively with the distributor and am currently waiting for an update to be done to this amp. Apparently there is a new revision under way with a switch to allow the amp to accept a stronger input signal. Hopefully I should be able to get my hands on a revised amp in about a month and be able to complete the review.
Mister X XP
Price: $110 plus shipping
OP-amp: AD8397 as tested (also available with
Battery Life: 8-12 hours as tested
Mister X’s XP amp is a PINT class amp meaning it is similar in design to Warren from tangentsoft’s PINT amp. The XP is newer and updated but has the great sound quality and energy of the original PINT that made it popular. While the other 3 amps reviewed are of Chinese design, the XP was designed and made in the US by a prominent member of several online forums. This amp can either be purchased as a complete amp or as a pcb to build your own. I purchased a completed amp and a board to try the build myself. This is not a build for amateurs though as it involves smd soldering.
The XP is housed in a Hammond aluminum enclosure and comes in either Silver or Black. The XP is probably the most durable amp reviewed, but it is also slightly larger. It comes with only a wallwart. No other accessories are included so you will need some sort of IC to use with it. It is also worthy to note that Mister X builds these amps per order so lead time can be up to 2 weeks. It took about a week for mine.
Sound:
The XP was by far the most detailed amp reviewed. It sounds the most like my home amps, and for a solid state amp sound surprisingly similar to my Little Dot II+ in some regards. It is warm and detailed. There is no turn on thump at all. While the XP may not be as exciting as some of the other amps, it is by far the most detailed and is fairly neutral as well.
Tchaikovsky
The XP tackled this recording with ease, showing the most instrument separation out of any of the other amps. The sound was very smooth with warm mids. It sounds a little less dynamic then the X-1 or LDII+ almost like the op-amp could have used a bit more power, but still very good. The amp handled the cannons very well and gave them a nice impact some of the other amps did not have.
Massive Attack
The track opens up with deep, deep bass which the XP handled nicely. Bass was strong and tight. It was not bloated like some of the other amps. Overall the XP has the best bass in my opinion. The vocals were very smooth and the XP was the only amp to really handle the stereo separation of this track well.
Staind
The XP handled this track the best out of the amps reviewed. There was good instrument separation, tight bass and smooth vocals. Cymbals were crisp and clear without the harshness exhibited by the other amps. The XP is very enjoyable for rock. When the track was over I just wanted to keep listening.
Conclusion
Overall I would have to say that Mister X’s XP amp is the best. It is head and shoulders above both the Xtra X-1 and LDM+. It is by far the most detailed and analytical amp of the group. It is larger, but not huge and still easy enough to use as a portable amp. The only downside is the battery life, which is not very long, but it lasts long enough that if I charge it about as often as I charge my Zen Vision:M I won’t have to worry about it.
The C&C Box was a bit of a letdown. I wish it did not clip from the line out on my Zhaolu, which does not really even have very strong outputs. I am looking forward to getting my hands on an updated sample to look at.
The Xtra X-1 is a very fun amp to listen to, but is not detailed enough for me. If you want a fast amp to enjoy your music on the go check this one out, but if you want to critically listen or listen to bassy music you’ll want to look elsewhere.
The LDM+ is a great amp at its price point, but the extra $30-40 to get a better amp would be worth it in my opinion
Out of this group Mister X’s XP is the clear winner. The C&C Box shows promise and hopefully I will be able to do a face off between the two either with the new version of the C&C Box or possibly with my Zen Vision:M as the source to even the playing field.
Update 6/11/07
Updated Test Setup :
Transport : Marantz CD5001
DAC : Upgraded Zhaolu 1.3
Interconnects : Blue Jeans Cable digital coax & Soloz Audio silver RCA-mini
Sennheiser HD580 heaphones with HD600 grills & Soloz Audio Cardas Cable
* These equipment upgrades do affect the sound, but should have no negative influence on the PA2v2. In fact, they give the PA2v2 an advantage over the previously reviewed amps.
PA2v2
Cost: about $65-70
Op-amp: LM4881
Battery Life: 100+ hours (unverified)
The PA2v2 is a good amp for the money. The amp comes in a small plastic case so I cannot give it higher than a B- for build quality. It accepts 2 AA batteries and comes with a wallwart so you can use rechargeable batteries. Also, there is no LED to indicate the amp is on or off. There is no turn-on thump. The amp comes only with a wallwart and a mini-mini IC. According to reports the included IC is too long for practical portable use and is not high quality. You will want to purchase a mini IC separately.
Sound:
I would not describe this amp as a very musical amp, but if you love bass this just might be the best little amp for you. Mids and highs are mediocre, Bass is plentiful with an in your face presentation.
Tchaikovsky
Overall the presentation of Tchaikovsky’s 1812 overture seemed flat and lifeless until the cannons fired near the end of the piece. Even then it was only the canons that really stuck out.
Massive Attack
Very pronounced bass line, but not muddy. The bass is not very extended. The PA2v2 has loads of bass that hits deep, but not as deep as the XP. Mids and treble are not spectacular, but they are not bad either. The PA2v2 retains the stereo separation, but you do have to listen closely to hear it.
Staind
The PA2v2 gives the song way too much midbass. It is overpowering, and drowns out the mids. Vocals are still strong. Highs are slightly harsh.
Updated Conclusion:
The PA2v2 was not my cup of tea. It was far too bassy at the expense of the rest of the frequency band. The amp has a slight boot at the high end as well, but left the highs feeling unrefined. The sound signature is almost like someone turned the loudness feature on a stereo, clicked up about 2 notches too high. This amp would probably be loved among bassheads.
Mister X's XP amp is still the clear winner.
Update 8/25/07
Microshar uAMP107B
Pictures coming soon!
Niko-Time was very generous to let me borrow this amp before he even had the opportunity to hear or see it!
Cost: $135
Op-amp: unknown
Battery Life: 100+ hours
The Microshar uAMP107B is a new version that came out only last month. The amp is enclosed in a small plastic enclosure, much like the PA2v2. The amp looks and feels cheap. An interesting feature (if indeed you call it that) is that the amp does not have a traditional power switch. Instead of a switch the amp uses a circuit to sense when plugs are inserted into both input and output jacks and the amp automatically turns on. The manufacture claims this is so the battery will not run down if accidentally left on in a bag. I talked with the manufacture about this and expressed my feelings that a switch would have been better for two reasons. First, I normally leave my portable rig set up and inside a protective case. I have to reach inside to turn on my DAP so why wouldn’t I be able to turn on and off my amp while doing so. Secondly, the amp has a very loud turn on pop, that you are forced to subject your headphones to because of the configuration. I did suggest the manufacture include a delay circuit so no sound is outputted for a few seconds after initial power on. I do not know if my words fell on deaf ears or if the next version will include a delay circuit. Only time will tell.
The amp came with a wallwart to charge the internal battery and a printed manual. Battery life is excellent. I am currently listening to the amp after about 80 hours of use still on the first battery charge, and it does not appear to be dying yet.
The Microshar uAMP107B does have a hiss that is audible on low impendence headphones. It was not present with my HD580’s but many other users have complained about hiss, making this amp hard to sell as a portable since most portable headphones have low impendence. This paired with the cheap feel and turn-on thump give the amp my lowest build quality rating thus far of a C. You will need to purchase a separate mini-mini IC.
Sound:
The Microshar uAMP107B sounds much better than it looks. I still would not call it a good value for the money though. Overall sound is good but not excellent, and there are other amps similarly priced that are better. The background noise and turn-on thump should make consumers look elsewhere.
Tchaikovsky
The Microshar uAmp107B is a pleasant amp to listen to, but it does not pull you into the music. It is somewhat lifeless sounding, aside from the punchy bass. The amp did provide good impact on the canons, but the soundstage seemed tight and only provided mediocre instrument separation.
Massive Attack
Once again the amp had good bass extension, but a slight bloat was present on the bass heavy track. Vocals were smooth, but the overall experience was not engaging.
Staind
This track also exhibited a slight bass bloat. Some might call this just punchy bass and find it a good thing, but I feel that it was just a tad overdone. The highs were ever so slightly sharp, but the mids were fine.
Updated Conclusion:
The Microshar uAMP107B is a good amp that is sure to have a strong following, however it is not flawless and the physical flaws ruined the experience for me. Mister X’s XP is still the best amp reviewed thus far, however I do have 2 more amps to review shortly and one of them is very likely to dethrone the XP.
Update 9/05/07
C&C Box+
Cost: $109.50
Op-amp: unsure
Battery Life: up to 80 hours
This review is really part two of the C&C Box v2 review from March of this year. You can go back and read my comments on the amp, but basically the amp showed a lot of promise, but the gain was too high and it could not handle the line level output from my Zhaolu DAC. The amp was driven to clip with every song I tried. Using the amp with my mp3 player did not cause the amp to clip, either using the headphone out or the line out via a LOD. It took the distributor several months to get me a replacement, but they followed through and kept good on their word and sent me one of the new + models. They were also kind enough to let me keep the v2, and told me to return whichever one I do not want to keep.
The C&C Box+ is very similar to the Box v2 in looks, but under the hood it is slightly different. The specs are different and the amp received a battery upgrade which gives the amp more power, and supposedly more battery life. In the short time I have had the amp it would appear that it does indeed have better battery life, much better battery life. The amp is also ever so slightly lighter.
The main change between the v2 and + models is the replacement of the mid-frequency extender found on the v2 for the gain switch on the +. Both amps have the bass and sound stage switch. While the switches do indeed affect what they are intended to change I prefer to leave them in the off position with the gain in the low position.
The included accessories for the Box+ are exactly the same as the Box v2. The case is the same on each amp, except for the lettering. Like the v2, the Box+ does have a slight turn on thump.
Sound:
The C&C Box+ is a great amp. It is not the littlest, the most neutral, most detailed, nor the best all-around amp reviewed here; but it does a good job with what it has, and sounds damn fine to boot. This is a fun amp that got my foot tapping, and it sounded good enough that I wasn’t distracted by the shortcomings, and enjoyed my music. The C&C Box+ is an excellent value for the money, and when you consider availability easily beats out the XP.
Tchaikovsky
The Box+ did a great job on this piece, not nearly as good as my reference amps, but it still did a great job at presenting just how dynamic this piece really is. The highs sounded very natural, and the amp brought the horns to life about 6 minutes in. The one downside is that the sound stage seemed constricted. I did play with the switches somewhat to see if I could get that wider soundstage, and the amp was able to present a wider soundstage, but at a loss of neutrality. Overall listening to the 1812 Overture on this amp was an enjoyable experience.
Massive Attack
One of the first things you’ll notice when playing this track is the deep synthesizer bass. The Box+ handled this bass quite nicely. It was deep and strong, but not overpowering. The amp also has good stereo separation and smooth vocals. The soundstage seemed much more realistic with this recording than with Tchaikovsky.
Staind
The C&C Box+ excelled here. The bass line was subtle, just as it should be. Highs were not shrill as some amps can make them be, and the vocals were smooth, yet grainy which anyone who is familiar with Staind can appreciate. Normally, my HD580’s don’t sound quite so good with rock and I end up reaching for my SR 225’s, but the Box+ paired very well with my HD580’s and Staind. After listening to Right Here I let the rest of the CD play through.
Updated Conclusion:
The C&C Box+ is a good amp, even better when you consider it costs just over $100 with shipping. It is cheap enough that many non-audiophiles will be able to consider it, but expensive enough that you don’t have to worry about getting something cheap or wondering if more $ would have gotten you a much better deal. It sounds good, is fun to listen to and is fairly neutral and detailed. When you consider that the amp is easily accessible you have a good deal that the masses can enjoy. The XP is slightly better, but you can’t buy it anymore.