HeadAmp Pico Power portable headphone amplifier

Introduction

I recently purchased the HeadAmp Pico Power (PP) and thought I would share my thoughts on this little gem of a headphone amplifier.

First of all, Justin, the owner of HeadAmp, was friendly and courteous in handling my questions via email before my purchase. I initially asked for a silver version, but Justin did not have a silver chassis available—he then sent me a picture of a grey chassis he had in stock, and since it was light grey, I opted for this color. I commented on his reputation for exquisitely made product, adding I was a huge fit and finish guy and very particular about any imperfections. He shared his concern that the chassis finish is hand polished and it may not be as perfect as I had hoped, but after speaking with him over the phone, I went ahead and ordered the amp. I was fortunate in that I only had to wait a week for him to ship my new toy.

When I received the amp, the product package was a plain white box with a large sticker on it indicating its content. The PP was nicely protected inside with cutout foam. Besides the PP, there was a one sheet owners’ manual, a very nice form fitting case in black leather, and two extra screw-ons individually wrapped that are used to attach the removable bottom plate which covers the battery compartment, a nice touch since I imagine it might be easy to misplace one of these when changing out the batteries. The included Duracell alkaline batteries were already installed. All in all, a simple presentation that eschewed any unnecessary expense.

After removing the snug fitting leather case, I inspected the PP closely. I’m not sure why Justin felt compelled to remark on the hand polished finish, that it may not be as perfect as I would want, but let me assure everyone reading this that, in my view, it was perfect. Not only that, but the seams of the aluminum chassis including the removable lid for the battery compartment were perfectly aligned. Very impressive attention to detail for a $475 product, in fact, the best build I’ve experienced in this price range, and I’ve been an audiophile for 40 years as well as worked in high end audio throughout my career.

Following my normal routine, I ran signal into the PP for a few days before I did any critical listening. The quoted life of 40 hours for alkaline batteries was accurate since I swapped these out for non-rechargeable lithium batteries during the burn-in process; I have no doubt the 120 hour usage rate for lithiums will hold true.

Impressions

My source gear is a MacBook Air repurposed for transport duties using the latest version of Audirvana (v3.5) as the music playing software. Connected to the MacBook is a Chord Qutest DAC which then connects to the PP. My music library includes CD rips from my collection as well as some 300GB of hi res files spanning most genres. The headphone I primarily used in my evaluation was the final D8000 planar magnetic (60 ohms, 98dB/mW).

So, can such an affordable amp as the PP be commensurate with a $3,800 headphone? I believe it can. First of all, as would be expected with a battery driven power supply, the PP is dead quiet. The D8000 has excellent retrieval of micro detail, and the PP’s absence of hiss or other noise floor artifacts result in a greater sense of spaciousness, especially width and depth wise. The tonal color of the PP is neutral, sounding very balanced throughout the frequency range. Trebles are presented cleanly, with no etched or sibilant nature that can take away from long listening sessions. In listening to Beth Orton’s album, Central Reservation, I noted her voice was portrayed without the grit I had heard with other amps, the PP reproducing the nuance, the subtle expression of her singing with an ease and smoothness that left me feeling rapturous. The D8000 is known for its bass quantity and quality, and I never felt the PP had to sweat in order to reproduce the slam of this planar headphone. Rated at 500mW into 32 ohms with an output impedance of 0.2 ohms, the PP appears to have ample power for low and medium impedance headphones with average sensitivity.

Conclusion

There is no editorializing of the sound by the PP, rather, it reproduces music with a level of purity that belies its accessible price point. Of course, others with different headphones and listening sensitivities may argue otherwise, but my feeling is the D8000 is a neutral instrument in which to evaluate this amplifier, therefore, my positive impressions no doubt should extend to others’ experience as well. Adding to the PP’s performance, it is made in the USA, the build quality is sumptuous, and it has a six year track record of reliable service ... what more can a headphone enthusiast ask from a reasonably priced product?

One of the well-known disadvantages of portable amps has always been, simply put, a lack of power available, being that they are limited to using batteries. While with in-ear monitors and more easy-to-drive headphones this isn't such a problem, it limits their capabilities when it comes to either high-impedance headphones (which sound best with amps that can consistently swing a greater voltage) and headphones such as lower-sensitivity orthodynamics (which sound best with amps that can deliver high amounts of current). While it is readily possible to cram a larger battery and more capacitors (to hold more reserve power for peaks in the music) in a case, the result quickly becomes ungainly in size.

It's not for want of trying though, with the recent crop of portable amps such as the Ray Samuels SR-71B and ALO Audio RXIII and International overcoming this with a balanced circuit -- basically double the electronics for greater power. The results with those have been much closer to desktop capability. However, once you have to consider re-terminating your headphones with the unusual plug (a regular TRS plug is no good) the cost starts heading towards 4-figures before one even looks at headphones (and well over for the top set-ups with a high-quality digital source).

Since coming out with what is very probably the world's smallest IEM amp, the Pico Slim, Justin Wilson of Headamp set his sights on making an amp that was both small, yet packed enough punch to use with full-sized headphones. That took him 2 and a half years, but the result, after painstakingly getting everything perfect is quite an accomplished amp.

Case quality, as always with Headamp products, is excellent. Switches for the power and 3-position gain are tiny, but that prevents them easily being bumped though they are easily manipulated. The headphone sockets are quality metal items the volume knob is short, more so than a right-angled headphone plug, but deeply knurled. Behind it is a teflon ring which makes it deliberately stiff (to prevent accidental adjustment), but smooth to turn. Along with the beautiful anodising and laser-engraved labels, a good leather case completes the picture, holding the amp firmly inside.

Unlike both the Pico, which contains a DAC, and the Slim, which contains a digitally-controlled volume and charging circuit, the Pico Power is purely an amp and nothing else. That allows it to hold 2 9V batteries while only taking up a volume pretty much only the case wall thickness over the size of about 4 of them. Compare that to the vastly larger O2 or Triad L3, both of which use the same batteries. This makes it far more reasonable in size, even with the included leather case.



Given the use of 9V batteries rather than a battery pack, the Pico Power allows some flexibility in what trade-offs can be had. Higher milliamp hour (mAh) re-chargeable batteries will give longer battery life at the expense of peak power, whereas lower mAh ones sacrifice usage time for higher power delivery. By default, the Pico Power comes with a set of Duracells. I found these lasted quite a while and I could still play music with the amp even after the power LED stopped lighting, letting me know I was due to change them out. While there isn't a charging port on the amp, changing out the batteries is a fairly straight-forward affair. Flip the amp over and undo the nuts, which you have to be very careful not to lose as they come off suddenly. A spare pair is usefully included with the amp. The battery springs are stiff and a firm grip on the amp is needed while removing the batteries. Some slightly over-size re-chargables are going to be tough to get in and out. With the batteries out you can admire the artful machine marks inside before inserting another pair.

Speaking of the case, it fits the amp very snugly, and I saw no reason not to include it when attaching the amp to my (trans)portable rig which includes a Fostex HP-P1. However, while the Fostex has a headphone amp included, I felt I got far better results when using it with the Triad Audio L3 driving headphones. Likewise, with the Pico Power, while I cannot compare both amps directly, since I sold the L3, I do feel I get similar results, with the Pico Power sounding less like it is making an effort to play the music than the HP-P1.

A recent addiction ..err.. I mean addition to my transportable rig has been the iRiver AK100. While the inbuilt headphone amp is ok, high-impedance headphones sound a bit muffled directly out of its headphone port and IEMs are somewhat limited by the higher than ideal output impedance. Adding the Pico Power in the chain to the former, music comes through more relaxed and spacious with instruments more clearly delineated and the soundstage wider. Sensitive, multi-BA IEMs likewise are controlled perfectly. The only disadvantage the it may have is that standard volume controls are not always perfectly channel balanced, unlike the more noisy electronic volume control used in the Pico Slim.

Using the gain switch and selecting a suitable volume level on the Pico Power, I can use the volume on the AK100 to precisely dial in the level I want. The slight stiffness of the amp's volume control means that it stays in place firmly. The amp is also dead silent, critical for playback with such IEMs.



Similarly, the Pico Power is a good match with devices such as the Audioquest Dragonfly and Meridian Explorer, which are limited by the amount of power that they can draw from a computer's USB port and thus their limitations when it comes to powering headphones. Even using a pair of highly resolving Tralucent Audio 1plus2 IEMs or my JH-13 customs and feeding my Dragonfly better power via an Aurorasound USB Bus Pro, I felt the Pico Power still managed to get a bit more out of fast-paced music such as Paco de Lucía, John McLaughlin and Al Di Meola playing on Friday Night in San Francisco. Each guitar note seem a very slight bit more clear and less harsh. Not surprisingly, comparing the ability of my iPhone 5 with full-sized headphones with and without the Pico Power there was no contest.



Some time ago I DIY'ed an Objective 2 amplifier to see what all the fuss was about. I brought it out to see how it compared to the Pico Power. With careful volume matching there wasn't a lot of difference, with the O2 seeming to be a tiny bit more detailed with my best recordings and the Pico Power giving the music a bit more "body" and being more overall listenable. What was interesting for me was to later learn that Tyll Hertsens over at Innerfidelity had measured the Pico Power and it measures phenomenally well.

Probably the only place the Pico Power falls down a bit in my experience is with orthos, which work best with high-current amps. My LCD-3s sounded rather asleep from Pico Power, unfortunately, though given my purpose in buying the amp, I'm not likely to be using it with them. The LCD-X and LCD-XC fared quite a bit better, given their higher sensitivity and more lively presentation, however, so while not a portable rig as such, as a somewhat heavy transportable rig, the LCD-XCs can easily be used with it and one's choice of source.

Overall, the Pico Power is a fantastic amp for most headphones, only excepting those with very demanding requirements, such as some orthos. If measurements mean a lot to you as well, you'll be happy to know that it measures exceeding well also. Cutting down the design to the basics combined with Justin's pursuit of perfect execution has resulted in an excellent amp.



Audioquest Dragonfly (with power from an Aurorasound USB Bus Power Pro), Pico Power and Symphones Magnums (Grados with custom drivers).

February 2014: More pictures:

[size=12pt]Presentation and Packaging[/size]
[size=12pt]I've been a long time admirer of Justin over at HeadAmp for quite sometime. I've loved his products in the past, but never have owned one. Well this was my chance to finally step into the world of high class sound from HeadAmp. I was very excited to open the box with my Pico Power nestled inside. The box was so small, but was a nice touch. The amp was well packed with foam inserts perfectly cut-out to insure safe delivery of a rather expensive portable amp. To my surprise, there wasn't much in the packaging. Many companies provide what I call "fluff". Sometimes those things are useful, but typically not needed and end up being thrown in a drawer and never seen again. The Pico Power was already slipped into its luxurious case that is made from soft, buttery leather. It has "Pico" embossed on one side, and the HeadAmp logo embossed on the other. Overall a very nice case, that fits like a glove and protects the amp very well. Other than the case, the package includes: A large card that shows the features, information about the batteries used, and his warranty policy for the amp, and a set of flat-head screw caps to replace the set already installed on the amp, in case they are damaged or break. That is it. No fluff, no coupons, nothing but pure basics. [/size]
 
[size=12pt]Just a few notes about the process of purchasing a select few of Justin's amps (Pico Power included). Be prepared for a long wait. Justin's products are very well made, almost to the point of being custom made, so the wait will bother some. His products are very well respected, and are a fine example of small company that competes with the best there is to offer. I personally didn't have a problem waiting a few months for my amp to be ready to ship, but some people will find the wait time to be unbearable, so please take warning on that. Also note that the Pico Power is "In Stock" now (July 8, 2013) at Justin's website - www.headamp.com. The initial batch of Pico Power's were sold out in a matter of days. It seems as though Justin may continue to keep the Pico Power in stock so that wait time will not be an issue. If that is the case, no worries and I'm very jealous. [/size]
 
   
 
[size=12pt]Build Quality and Form Factor[/size]
 
[size=12pt]What is there to say? If you know anything about Justin's amps, it is that they are made with the highest quality materials and assembled by hand to insure top quality control. I would consider his company boutique and it is run like one. The full enclosure (including the battery cover) is made from precision machined aluminium and is anodized to look and feel sleek and smooth. The quality is truly top notch and I can't say that I have every felt something built better in regards to portable devices. The amp is offered in a variety of colors that include: Black, Silver, Grey, Red, Orange, Blue, and Purple. I choose the Black color options just because that is the way I roll, but I have seen the Purple variation and it is simply stunning. The volume pot is also well built, and very smooth. The knob could be a tad larger for bigger hands, but it is acceptable for a portable device. I can understand why Justin choose this size of knob so that it would not protrude much for risk of damage. The jacks (3.5 input, headphone output) are both secure and don't wiggle at all. I have experienced other headphone outs that wiggle a bit and don't securely grip the jack, but that is not the case with the Pico Power. The On switch and the selectable gain switch both have good resistance to them and don't feel cheap at all. They don't seem like the type of switches that will break after a year of use (I'm looking at you ALO). The LED light indicator is not too bright, nor too dim, it is just right. I've found that is shares very similar lumination to the Headstage Arrow 4G. Overall the quality of this amp is without a doubt the best I've ever had the privilege of owning. Has the same, high quality feeling as Justin's desktop amps, and that is saying a lot in the portable world. [/size]
 
[size=12pt]When I first ordered the Pico Power, I was expecting this large enclosure similar to some of the RSA offerings or even as big as the Lisa 3. To my pleasant surprise the Pico Power has a very humble footprint measuring smaller in size than the FiiO E12. It is a tad thicker, but the dimensions are actually smaller. In the features, Justin states that the Pico Power might be the smallest 2x9V amp there is. It is no bigger than an iPod Classic, and is only 0.1" thicker than the actual 9V batteries. A very hard thing to pull off, but Justin has passed the test with flying colors. [/size]
 
[size=12pt]The actual dimensions of the Pico Power are: 4 3/8" (L) x 2 1/4" (W) x 3/4" (H). [/size]
 
     
 
[size=12pt]Size Comparisons [/size][size=12pt](more to come) - [/size]
 
    
 
[size=12pt]Sound Quality[/size]
 
[size=12pt]So the question at hand is how does it sound? How does your other gear sound? Because that is how the Pico Power will sound. The Pico Power is as neutral as it’s going to get.[/size]
 
[size=12pt]The first question that I like to start off with is: What sets the Pico Power apart from its competitors? Well, there isn't one answer to that question, but for the sake of my review... I would say it would have to be the Pico Power's unmatchable way of presenting music. This amp is truly wire with gain. Similar to many of Justin's other amps, the Pico Power is simply the most neutral presentation I have heard from any portable amp (I've heard quite a few - and have owned a fair amount). The first time I turned on my Pico Power, it was plugged into my iPod Touch 4G + CLAS and wow was the sound magical. I was getting no coloration what so ever. Off first impressions, I couldn’t characterize the Pico Power because it didn’t have any characteristics. Whatever your gear sounds like, is exactly what you are going to hear. The Pico Power builds on what is there, and makes it that much more refined. The bass has more control. The notes have more weight and the treble is very detailed. Using my Tralucent 1plus2 IEMs, the sound was just specatuclar. I was using my 1plus2’s with my AK120 alone, but after hearing the Pico coupled it is hard to go back. Every aspect of the 1plus2’s that I enjoyed so much was enhanced and taken up a notch. One thing I should mention is that the Pico Power is very revealing. Because of its nautral ability to represent music with supreme neutrality, it can sound incredible or like glass shattering depending on your source. You can’t expect this amp to mask or somehow make the sound quality better if you don’t feed it quality. But if you do, the sound is truly among the top in the portable amplifier world.[/size]
 
[size=12pt]The sound was simply better than some desktop amps I've heard. At the time, I had a modest setup at my work desk which included a Matrix M-Stage, coupled with my Asus Xonar Essence STX sound card running as the DAC. This setup brought me great sound quality while on the cheap, and was sufficient enough to power my Mrspeakers Mad Dog headphones. When I replaced my M-Stage with the Pico, to my surprise the sound was actually better. The definition and body of the songs sounded more full and the low end was something else. One of the greatest sound features of the Pico Power is the way it renders bass. It doesn't emphasize any part of the spectrum, but improves on the existing sound with more weight and body. The bass reached low, and has great punch with the Mad Dogs. The vocal were liquid smooth with no sign of harshness or sibilance. The treble was very refined and well extended. The amp simply represents your source and headphones the way they were meant to sound. If I could compare the tonality and sound signature of the Pico Power it would be very similar to the GS-1 desktop amp. They sound very similar, but the difference is you can travel and be on-the-go with this! Never did I expect such a small package like the Pico Power to match desktop quality sound, but I'm glad I gave it a shot because this amp truly is remarkable.[/size]
 
[size=12pt]The Pico Power's price tag is quite high, so I decided to give the little guy something that matched it in regards to prestige. Recently I had the opportunity to compare two different setups using the Pico Power as the common denominator. For my first setup up the components consisted of: IPC 7G 160GB (Rockboxed) + Whiplash Audio Custom Twag v2 LOD + VentureCraft Go-Dap DD Socket 1 "Limited Edition" 12V (w/ opamp MUSES02) + BTG Audio SPC Micro Mini to Min + Tralucent 1plus2 (w/ Uber Cable). My second setup consisted of: AK120 (Stock 1.0 FW) + ForzaAudioWorks Claire ICS Mini to Mini + Tralucent 1plus2 (w/ Uber Cable). What an adventure. I still consider myself a young gun to the more experienced folks in this community, as well as a hardcore headphone enthusiast but these two portable setups simply stunned me. I couldn't believe what I was hearing. Never in my wildess dreams did I think a portable setup could match the likes of some of my desktop setups. Well, they did. They still have a few notches to go to match my main setup, but the ability to be portable/transportable (i.e battery powered, durable, and small) this amp really did impress. Each setup had a different flavor, but my preferred portable setup for on-the-go is a slightly warm neutral presentation that is never harsh are sharp in the treble, while maintaining good extension and smooth treble. Overall I preferred the AK120 + Pico Power, but the VentureCraft setup actually did better with my full-sized cans. I would assume it has to do with the fact that the AK120 doesn't have a true line out, but that is just speculation. [/size]
 
[size=12pt]Final Thoughts[/size]
 
[size=12pt]Overall you are getting one heck of an amp, not limiting to just portable amps, if you are considering the Pico Power. It has tons of power to drive headphones such as the Beyerdynamic T1, LCD-2, HE-500, or HD800. It can perform very well against moderately price desktop amps such as the M-Stage, D100, HA-160, just to name a few I've heard and can attest to. It has a small foot print considering its power output and perfectly stacks with DAPs such as the iPod Classic, Touch, and AK120. If you are looking for a portable amp that has a neutral presentation, and doesn't color your music than the Pico Power might be for you. It takes what you hear and improves upon it in all departments. Simply an amazing product that I'm happy I took the dive on. Is it worth the price? For me it was, but for some that believe value is #1 priority might think this amp is a bit too expensive. Let me tell you, that you won’t want to try another portable amp. It meets all expectations for me, and has very few flaws (I’m being highly nitpicky here). If you can get past its battery-only configuration, the somewhat cluttered in’s and out’s, and the cost then everything else will not disappoint. [/size]