Headphone Amp mini-roundup

soloz2

Limp Gawd
Joined
May 19, 2006
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430
Portable Headphone Amplifier Review



While I may be somewhat knowledgeable about headphones and amps 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
Microshar uAMP107B Product & Ordering Info
C&C Box+ Product & Ordering Info
AMB Labs Mini3 built by MisterX Information
RSA Tomahawk Product and ordering 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 adds review of PA2v2 Here
Update 8/25/07 adds review of Microshar uAMP107B Here
Update 9/05/07 adds review of C&C Box+ Here
Update 10/20/07 adds review of MisterX Mini3 Here
Update 10/20/07 adds review of RSA Tomahawk Here
 
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Conclusion
Overall I would have to say that Mister X’s XP amp is the best


Was there any doubt;)
 
I haven't listened to the pa2v2. from what others have said it's rather bassy and not as neutral as the LDM+ so I was never that interested in it. All 4 amps I purchased with my own money so that was also a limiting factor. I also still have all 4 amps on hand. I'll be selling the LDM+ and Xtra X-1 shortly though
 
nice roundup.. I hate you though.. cause I am looking to upgrade my portable and I am broke at the moment. hehe :D
 
nice roundup.. I hate you though.. cause I am looking to upgrade my portable and I am broke at the moment. hehe :D

don't hate the messenger! :D

if you don't have a lot of $ buying used is a good idea! I am the 2nd owner of both the LDM+ and Xtra X-1. I purchased the C&C Box from a group buy so it was a few $ cheaper then retail and well I paid full price for the XP, but I considered that the best investment as I also bought a pcb and plan to try my hand at duplicating Marshal's work. :D I consider it a double learning experience!
 
Nice roundup.
I've been going back and forth on the C&C and a LDM+ for like a week now. Mister X's XP has been taunting me as I know it's good.

Thanks for that. Now to start stashing some cash away.
 
I have the LDM+ and its.. well.. ok. I wasnt impressed by its output volume wise. Buildwise.. well.. the screws popped off the back of mine and ive spent now at least 4 hours of my time trying to get them back in. Sometimes I can get 2 back in.. but usually one will come back out while trying to put in a third. The problem is the place the screws go arent really threaded. They are kinda just jammed at an angle into the corners. Sadly.. I ended up using some tape to keep the back on. So its ghetto now. Sure I can ship the thing back to get the screws put back on, but that would just be more money out of my pocket on already mediocre amp.

Now im just looking for a USB/DAC amp for my pc and will just end up tossing this in a drawer :(
 
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&#8217;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.
 
is there a link for where i could purchase the pcb for mister x's xp amp and/or a parts list? i'm looking at building an amp this summer, and this looks promising.
 
soloz2, the PA2v2 sells for 60$us shipped if purchased from Gary, not 65-70$.

That's strange that it didn't come with a mini cable, mine came with one...... although it was a long budget one that wasn't really worth much. Where did you buy it again? Perhaps he decided to stop shipping it with the mini cable.

And lastly, are you sure there is no on/off LED? Unless Gary revised it, there is a large Red LED inside the amp that lights when the power is turned on. Perhaps yours is broken.....

That's sad to hear the LDM+ didn't preform that well.

Interesting comparison between the budget portables!
 
I actually borrowed the pa2v2, so it could have been provided with a mini IC that the owner did not pass along to me. And no, the LED only lit when the amp was plugged in, it did not lit when powered by batteries.

The price I quoted was an average of ebay auction prices.


I do feel that the LDM+ is a better amp for the money.
 
the pa2v2 that i loaned to soloz2 has the mini cable but i didnt include them since theyre pretty long and not that good..and soloz2 make better IC so i guess he should use his own.:)
 
Update 8/25/07

Microshar uAMP107B




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&#8217;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&#8217;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&#8217;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.
 
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.
 
But you can buy a Mini3. ;)
(which is why the Xp2 concept never went beyond the design stage)

Yes, I'm quite aware of this and would like to give one a listen... but alas I'm broke. The next amp in line to be reviewed is an RSA Tomahawk and I'm really liking it! ;) too bad it'll be my last purchase for quite some time though!

if you want to send me one to review I'd be happy to do so! :D
 
heard so many good things about marshall's mini3 i ordered one a few days ago, eagerly awaiting it, damn usps need to hurry it up :D
 
I just received a package from MisterX, I haven't opened it yet, but there should be a mini3 and an XP in there so keep watch ;)
 
October 20th Update
It has been some time since my last update. I know that I promised to add the RSA Tomahawk a while go, but I’ve been waiting on another addition that I knew I would be able to get my hands on, the Mini3 portable headphone amp from Amb Laboratories. This is an exciting new DIY amp that has only recently become recognized for how good it truly is. I wanted to get one, or build one myself a few months ago when the new boards became available, but due to lack of funds put the idea on the back burner. However, I was able to get my hands on a Mini3 at very little cost to me through a very generous offer from MisterX. Yes, this is the same MisterX who designed, built and sold the XP amp that I have previously reviewed. Sadly it is no longer in production, but MisterX is not sitting by idly. He is one of the few professional builders of the Mini3 amp and was gracious enough to let me borrow a brand new Mini3 to review as well as his personal XP amp for comparison. This update will include not only the Mini3, but also the Tomahawk.

AMB Laboratories Mini3

Cost: $125, as reviewed $165
Op-amp: depends on version, as tested: AD8397
Battery life: depends on version, as tested: about 6-8 hours
http://www.amb.org/audio/mini3/

This space reserved for future pictures

This unique little gem is a wonderful headphone amp that while portable is good enough to serve as a desktop amp (taking into considerations battery usage of course) and would make an excellent choice to use in a computer rig with the addition of an Alien DAC or a good sound card. The Mini3 is the exact same size as the XP as it uses the same Hammond metal case. These cases are very durable and put the Mini3 at one of the most durable headphone amps period. You can order the boards from Amb Labs and build the amp yourself following the instructions on the website or you can order a pre-built amp from one of several professional builders. I highly recommend MisterX for the job as he does great work. Of course part of allure of DIY is getting your hands dirty, but I understand that is not for everyone, and I would not recommend this project unless you are familiar with electronics and handy with a soldering iron.
The amp MisterX loaned me is the basic performance version with a tweak to the charging circuit that MisterX added. This dramatically cuts charging times, which is good because battery life on the performance version is not very long. If battery life is important to you a slight change can be made when building the amp with will yield less current output and extended battery life.
Build quality is top notch. My only complaint is that the input and output jacks aren’t as nice as the ones found on the XP. This is really a minor detail. On the other hand, the Mini3 MisterX provided me with had the milled endplates which is a $40 option. These endplates add a professional touch to the amp and label everything. Additionally, there is a LED on the back to indicate battery charging status, a very nice feature that I wish all battery powered amps had. MisterX provides a wallwart with all Mini3’s he sells unless you already have a suitable power supply. He will recommend a quality place to get an interconnect, but one is not supplied. This might be an issue for someone trying to put together a system on a budget, but in all honesty most cables that are included with portable amps are throw aways anyway.
Sound:
Sound quality is superb. As I have already hinted, I find that this amp is good enough to be used not only on the road but as a component in a home system. The only downside to this type of use is battery life, however without the added charging tweak the amp should be able to be left plugged in for longer periods without any issues. I don’t think this amp could take the place of a desktop reference headphone amp, but it can definitely compete with other amps costing several times its cost.
Since MisterX loaned me his personal XP for reference I will include some remarks about the sound quality of the Mini3 compared to the XP. Please refer back to my original comments about the XP. I also think it warrants note that MixterX’s XP is slightly different than the XP that I previously owned and reviewed. The main difference is that my XP worked better with high Z headphones such as the Sennheiser HD580’s used. Also, MisterX’s XP had slightly less bass. Otherwise they sound very similar.
Tchaikovsky
One of the first things one notices when listening to a Mini3 is the bass. It has a very nice punchy sound with plenty of slam. While bass doesn’t extend too terribly low, it has very good bass extension for a portable amp. This translates into very nice impact from the canon fire. The highs are nice and clear with more treble extension than the XP. A nice wide soundstage helped articulate the instruments. Overall the Mini3 presents a nice fairly neutral sound.
Massive Attack
Once again the Mini3 shows its prowess in the low frequency department. The Man Next Door has deep synthesizer bass and the Mini3 made my Senns sing with just the right amount of slam. Vocals were smooth, almost sweet. The highs seemed slightly rolled off, but this could have been the combination of the bass line and the slightly warmish presentation of the amp.
Staind
This is one of my favorite songs so it is always enjoyable for me to see what a new amp will bring to the song. The Mini3 still had lots of impact on the kick drum, the guitars sounded as they should with crisp clear highs that seemed slightly shrill towards the end of the song.

The Mini3 is an excellent sounding amp. It is a slight improvement of the XP in almost every way. It is more detailed and spacious, without losing the fullness of the music. The amp has impactful bass, but it doesn’t overpower the other frequencies. Overall I would say this amp is slightly warmish of neutral.
 
Ray Samuels Audio Emmeline The Tomahawk
Cost: $295 plus shipping
Op-amp: unsure
Battery Life: simply amazing, the best I’ve seen.
http://www.raysamuelsaudio.com/products/tomahawk
The Tomahawk might be considered the odd amp out in this mini review. It easily costs about three times as much as the next expensive amp, yet is the smallest and doesn’t have a built in battery charger. Instead it uses two AAA sized batteries that lost a long time. I purchased mine a few months ago used and have not changed the batteries since I got it. Another thing that makes this amp unique is that is was design and built specifically to drive IEMs. The Tomahawk has a gain switch. The low setting has a gain of 1 and the high setting has a gain of only 4. Most of the other amps reviewed have a gain of 4-8. But don’t let the low gain numbers fool you. The Tomahawk can easily drive my HD580’s.
The Tomahawk is housed in a very small metal enclosure that was designed specifically to house the Tomahawk, so there are no other amps that use the same case. The rear panel has thumbscrews for easy access to the battery compartment. Build quality is superb as with all RSA amps. The Tomahawk comes with a sturdy box, warranty paperwork and a nice little pouch to keep the amp from getting scratched. As with the Mini3 Ray does not include an interconnect but will help buyers choose a quality interconnect for their system.
Sound:
Sound quality is nothing short of excellent, and one would expect great things for a portable amp of this stature and price tag. The first thing that I noticed when listening to a Tomahawk for the first time was the low noise floor. This amp is dead silent, and any amp with the goal of driving IEMs and other high sensitivity portable headphones needs to have a low noise floor. The Tomahawk is also incredible detailed and airy.
Tchaikovsky
The Tomahawk is the most detailed portable amp I have spent time with to date. It is very dynamic sounding with rich full bass and silky smooth highs. The Tomahawk presents the canons with umph. The sound is very detailed, but not lean as is sometimes the case.
Massive Attack
The Tomahawk presents the bass line as very deep with both impact and tightness. The vocals are silky smooth. The song makes good use of cymbals that is largely lost on other lesser amps, but the Tomahawk’s extended treble brings them forth where they should be.
Staind
The bas is clean and tight with slam that really brings out the kick drum. Guitars are strong and grungy. The Tomahawk also made it easier to distinguish between the individual guitars. The highs were crisp and clear as were the vocals.
The Tomahawk is a great amp that is in a whole another class in regards to both price and sonics than most of the amps reviewed. I would say the only amp that can really compete is the Mini3. Build quality and sound quality are both top notch. The Tomahawk is an amp that will help you get the most out of your portable system. You will need to invest in a quality source and interconnect to get the most out of this amp. You will also need to have a fairly good set of IEMs or portable headphones to really get your money’s worth. But if you have all these things then the Tomahawk is a clear winner and is worth every penny.
 
Updated Conclusion:
The XP, Mini3, C&C Box+, and RSA Tomahawk are the best amps reviewed. For this review I will break it down and share a few thoughts and comments on each.

The XP is a great amp. At one point I ranked it as the best amp reviewed, but due to availability and the pool of reviewed amps expanding it got dethroned. This in no way makes it a bad amp. Having the opportunity to listen to another XP only reaffirmed my belief that it is an excellent amp. You cannot purchase this amp new anymore, but used ones come up every now and again and typically go for around $90. If your budget is $100 and you see one buy it before anyone else does and never look back. It’s a great little amp that will serve you well. It’s a shame that you can no longer purchase it new, but I understand MisterX’s reasoning.

The Mini3 is a great amp for the money. It cost just a bit more than the Box+, but offers slightly better sound quality. It is more detailed and airy. It bests the XP as well. This amp has great bass slam so if you like a lot of bass, but still value clean detailed music then check this amp out. If you are confident in your ability and want to build an amp this is a great project. Overall the Mini3 is a great amp that is a good value for the money. It can compete with amps costing much more. I would say the Mini3 gives you about 92% the sound of the Tomahawk for almost 1/3 the price. That’s a great value for the money.

The C&C Box+ has some advantages over the Mini3. It costs less, is smaller and lighter, and it looks better. It has several switches including a gain switch on the back panel that gives you more control over your music. Personally, I keep them all to off so this does not affect me, but I know having the option may appeal to some people. The area where this amp shines is rock. If you have a pair of Sennheiser cans and listen to a lot of rock then definitely check this amp out. If you listen to a wide variety of music then I would have to swing my vote to the Mini3 as it is an all around better amp. It is more detailed and has a lower noise floor. It is also more neutral.

The Tomahawk is the best amp reviewed here. It has the lowest noise floor, offers the most detail, has excellent battery life, is tiny and looks great. It is also the most expensive amp. As I previously mentioned you need a good system to take advantage of this amp. If you are not using a source with a line output and a LOD you are probably wasting your money on this amp. However, if you are looking for one of the best portable amps then this is a very strong contender. Often one must sacrifice battery life or size for great sound, but the Tomahawk seems to have the whole package, great sound, long battery life, and a small footprint. The ability to drive both portable and full-sized cans is also a plus.

Please keep in mind that this review is entirely my opinion.
 
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