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Review: Portable amp roundup! 56 portable amps reviewed and compared - FINAL update 12-20-10 added RSA SR-71B  

post #1 of 3234
Thread Starter 

NOTE: This is a SUBJECTIVE Review that has occurred over a long time horizon. All observations, rankings, and comments are my personal opinion and nothing more. For testing Methodology please see post#8.

Some pics of the initial batch of amps reviewed:

#1: from top to bottom, the RSA Hornet, Little Dot Micro+, Practical Devices XM4, Xenos 0HA

#2, from top to bottom: RSA Tomahawk, RSA Hornet, XM4, Headphonia, Larocco PRII

#3, from left to right - Headphonia, Larocco, Tomahawk

> Xenos 0HA

Info: http://www.aptecpro.com/products.html

The 0HA is the least expensive amp I reviewed, but it was not the worst sounding. It’s a very decent little amp. It has no real features and has no facility for use with AC power (nor, obviously, for battery charging). Also, the 0HA in my posession is not the latest version, for what that's worth.

Build Quality: B+: It’s sturdy, but it’s plastic. There is a turn on thump, but it’s not scary loud. Battery access is easy. The amp exhibits some noise at the very top end of the volume control, but that will likely never be used.
Treble: B: grainy and veiled compared to the RSA Hornet. Mid-treble is a bit too prominent. Top end extension is not great, and it lacks “air”. This isn’t the amp’s strong suit.
Midrange: B+: slightly veiled and slightly forward, but respectable.
Bass: A-: punchy, ample, with very good definition. Quite deep and powerful.
Neutrality: B+: Pretty even, a bit of bass push
Soundstaging: B-: Flat soundstage with mediocre width.
Transparency: B: acceptable transparency, but nothing to write home about.

Overall, for the money especially, the little Xenos is an amp I could live with, but I’d be yearning for an upgrade.

NOTE: I review the newer 0HA-REP below.

> Go-Vibe V5

Info: www.go-vibe-headphoneamp.com coming soon!

My Go-Vibe is the low-gain version, since I listen at moderate levels. Still, I never had the volume control past 12:00. The amp does not come with an AC adapter, nor will it charge batteries. Really this is a pretty basic amp – no “features” at all, like the Xenos.

Build Quality: B+: It’s Plastic Hammond cases will never score higher than a B+ for me in build quality, but there is no issue with the GV5. There is a zero turn-on thump. Battery access is easy. The amp exhibits very little noise at all.
Treble: B-: grainy and veiled. On the spitty and splashy side. Top end extension is not great, and it lacks “air”. I did not care for the GV5’s treble presentation.
Midrange: B+: generally smooth and clean, but a little laid back.
Bass: B+: a little light, decent definition and depth.
Neutrality: B+: weak at frequency extremes and a bit dark sounding.
Soundstaging: A-: nice width, decent depth – good performance here.
Transparency: B: Feels like the window into the music isn’t really 100% clean.

Overall, the Go-Vibe 5 wasn’t my cup of tea, although it might be just the ticket for people who want a portable amp for using with headphones that are on the bright side like some Sony’s and AT’s. Also, I should mention that Norm at Go-Vibe's customer service is fantastic. I ordered a regular gain GV5 when I needed a low-gain, and Norm sent me a low gain and then just had me main the )unopened) regular gain version to his next US customer. What awesome service.

NOTE: There is now a Go-Vibe V6.

> Headphonia

NOTE: This amp is no longer available and I have deleted the detailed review in order to save space in the thread.

UPDATE 3/20/07:

Something has come to light that makes it impossible for me to recommend the Headphonia amp anymore without some reservation. In any case, it's no longer available.

> Ray Samuels Audio The Hornet (M Version)

Info: News - Ray Samuels Audio

The Hornet really served as the reference or control amp of the group – I always compared each of the other amps to the Hornet. Why? Well, it’s a fantastic amp. It’s not quite perfect – it’s lone drawback, for me, is a slightly aggressive upper midrange/lower treble. But even this is sometimes more of a benefit than a liability. Otherwise, the Hornet is a world-class portable amplifier.

Build Quality: A: Excellent, attractive metal case. Solid jacks. There is a zero turn-on thump. Battery access is kind of difficult, but there IS a battery charging circuit, so I was not likely to remove the battery. The amp comes with a charger. The amp exhibits zero noise at all, and I mean zero. Dead quiet. Best of the bunch in that regard. Has a gain selector switch.
Treble: A: clean, grain-free, extended and transparent. No excess sibilance or bite, but ever so slightly forward lower treble.).
Midrange: A-: smooth, clean, and open – again just that little but of upper-midrange emphasis prevents a perfect score, but really this isn’t a big deal.
Bass: A+: powerful, deep, tight, punchy – awe inspiring, actually. Bass performance I thought only home amps and their much bigger power supplies could really provide. The Hornet is unparalleled in this regard. Jaw dropping bass performance, which never ceases to amaze me, even after having owned this amp quite a while.
Neutrality: A-: slight lower-mid/upper treble emphasis again prevents a perfect shore here – very neutral otherwise.
Soundstaging: A-: excellent depth and very good width – I sometimes wish the soundstage were just that one notch wider.
Transparency: A: Among the very best in this regard – has that “wow” factor of feeling a wide open window to the music, like the Headphonia, Tomahawk, and the PRII.

Overall, the Hornet is an amazing sounding amp, and the one I recommend to people the most often and with the least hesitation. The PRII may exceed it slightly in some performance aspects, but both PRII itself and its maker are sufficiently idiosyncratic that I am hesitant to recommend people pay the $125 extra for the PRII than the Hornet. Ray Samuels is among the very best in the business at customer service, and the Hornet, in addition to being a terrific amp, is tough as nails. It ends up coming in second in this round-up, but I recommend it first.

> Little Dot Micro+

Info: Little-Tube

This is the second least expensive amp in the group, and for the $60 price has a built in Li-Ion battery and comes with a charger! Quite the bargain. No other features. Unfortunately, it’s the worst sounding and noisiest amp of the bunch.

Build Quality: B+: Nice metal case, but the volume knob is cheesy, and the jacks are a little tough to jet plugs in and out of for some non-obvious reason. There is no real turn-on thump, but the volume control makes noise when adjusted, and the amp in general is noisy. There is an audibly hiss at all levels that increases with volume, and at the top of the range (which admittedly is unlikely to be used) there is a high-pitched whine that’s audible..
Treble: B-: grainy and veiled compared to the better amps here, lacks air and extension – not too transparent.
Midrange: B+: generally smooth sound here, pleasant presentation, without the last word in cleanliness or openness.
Bass: B: decent impact and quantity, but loose and lacking definition and depth.
Neutrality: B: not extended, slightly spitty lower treble, slightly dark mids, missing deep bass.
Soundstaging: B-: closed-in sounding – the most of any of the amps here.
Transparency: B-: colored enough that it completely lacks that feeling of having an open window to the music. There is a serious veil in between the listener and the music.

The issue with the LDM+ is that the even less expensive Xenos 0HA blows it away, so I can’t even say “sounds good for the money”. I find the LDM+ impossible to recommend even at the price.

> Larocco Audio Pocket Reference II

Info: larocco pocket reference II

In some ways, it’s a stretch to call this a portable amp, except that it does run on batteries, and I do use it as a portable amp. But it’s HUGE compared to the rest of the amps here – and heavy. It’s more than twice the size of my 80GB iPod. And it uses a ¼ inch headphone jack – not really a “portable” amp plus. It’s also drop-dead gorgeous – almost audio art. And sonically, except for one important idiosyncrasy, it’s phenomenal. But let’s deal with that idiosyncrasy now – the PRII isn’t dead quiet with any headphones, but it can be too noisy to be useful with very low impedance headphones like the Shure E500. To use the E500 with the PRII I have to use an Oehlbeck 120 ohm adapter, at which point the system is quiet. With headphones that are safely over 120 ohms, it’s pretty quiet, although not as quiet at the RSA Hornet.

That aside, however, the PRII is a phenomenal sounding amp – like the Hornet, it constantly amazes and delights me with its sound quality, which is surely on par with many home amps.

Build Quality: A+: Excellent, attractive metal case. Solid jacks. There is a zero turn-on thump. Can’t assess the battery access since the batteries were pre-installed and there is a battery charging circuit, so I have never removed the batteries. The amp does not come with a charger, and it should. Feature-wise in addition to the charging circuit there is an incredibly well implemented, if subtle, bass boost feature which operated only on the very low bass, but does improve deep bass performance while adding zero coloration.
Treble: A+: clean, sweet, lush, grain-free, extended and transparent. Great air and extension, totally natural. The gold standard.
Midrange: A: smooth, clean, and open – and liquid, while being tonally dead neutral. Again, reference is deserved here.
Bass: A: Ultra-deep and powerful, with amazing definition and speed. Good impact, but not quite as punchy as the Hornet.
Neutrality: A+: unquestionably the most sonically neutral across the entire frequency spectrum of any of the amps I reviewed. Unparalleled in this regard.
Soundstaging: A-: excellent depth and very good width – I sometimes wish the soundstage were just that one notch wider.
Transparency: A: Among the very best in this regard – has that “wow” factor of feeling a wide open window to the music, like the Headphonia, Tomahawk, and the Hornet.

So the PRII is an awesome amp, to be sure. It’s big and heavy for a portable amp, is expensive, and doesn’t work with every headphone perfectly. But it sounds OOOOOOHHHH so good with the right headphone. It’s dreamy. I’m glad I own one.

**** UPDATE 2/20/07: I got my PRII mk 2 last week. It was a 3 month wait, and was kind of angst-ridden, but I have it. And it is awesome, no doubt about it. While I do not have the original PRII to compare it to, it easily betters every portable amp I currently have. There is no doubt that the PRII mk 2 is still the king of the hill, as far as I am concerned. If anything, I'd upgrade the soundstaging to an A, and also note that in low gain mode only my E500's hiss. The PRII is still not a good choice for IEM users. But otherwise - it's the best portable amp I have ever heard.

That said, Larocco Audio is horribly frustrating to deal with, and there is real reason to avoid doing business with them. Their communication is terrible, and the wait for getting a product you buy from them is maddening, and exacerbated by the lack of communication. As such, while I love the sound of the PRII mk 2, I find it very hard to recommend to anyone, based on the poor business methods employed at Larocco Audio. DO NOT buy one of these from Larocco Audio until you have done some research on this site to fully understand the situation.

> Ray Samuels Audio Tomahawk

Of course, the main “features” of the Tomahawk are size (or lack thereof), and the crazy-long battery life. It really defines portable amp from that perspective – by far the smallest amp here – by far. But it sure doesn’t deliver the smallest sound.

Build Quality: A: Excellent, attractive metal case. Like the Hornet, the amp exhibits zero noise at all, and I mean zero. Dead quiet – a major plus. Has a gain selector switch.
Treble: A-: clean, grain-free, extended and transparent. Lacks the last little bit of treble air that the Hornet and PRII have, but it also lacks the slightly forward character of the Hornet’s treble, and in some ways I preferred the Tomahawk’s treble presentation to the Hornet’s.
Midrange: A: smooth, clean, and open – the Tomahawk’s wide open mids definitely give you that “holy poop this sounds good” feeling. The mids are really wonderful in this mini-mite.
Bass: A-: lighter that the Hornet’s bass, even after extensive break-in. Similar in quality and quantity to the Headphonia. Deep, tight, and well defined, but not as powerful as it could be. Maybe this is where the tininess of the amp has some impact? Still, bass performance is very good.
Neutrality: A-: except as noted above, remarkably neutral amp.
Soundstaging: A-: very good depth and width. Nothing spectacular, but very solid.
Transparency: A: Right up there with the best in this regard – has that “wow” factor of feeling a wide open window to the music, like the Headphonia, Hornet, and the PRII.

The Tomahawk is capable of driving all kinds of headphones in spite of being designed for IEMs. But since it was, I did spend a little extra time listening to the TH with the Shure E500’s, and that is an excellent combination. I’m pretty sure from now on, when I travel (which is 2-3 times a month), I will be bringing the PRII and the Tomahawk with me.

> Practical Devices XM4

Info: Practical Devices Corporation

The Practical Devices XM4 is medium sized – bigger than a Hornet but smaller than a Go-Vibe. It’s feature rich – defeatable AND adjustable crossfeed, defeatable battery charger, defeatable bass boost. That’s a lot of features in a $130 amp.

Build Quality: B+: Nice metal case. Jacks were a little loose but this had no audible consequence.
Treble: B+: some veil and grain, and the low treble is a little spitty. Lacks ultimate air and extension. Not bad, but not great.
Midrange: A-: pleasant sounding, warm and lush, maybe just a bit forward.
Bass: A: Deep, tight, powerful, and well defined – even without the bass boost! Excellent bass performance.
Neutrality: A-: except as noted above, generally neutral amp but a little warm.
Soundstaging: A-: Very good, and with crossfeed truly excellent.
Transparency: A: Right up there with the best in THIS regard – has that “wow” factor of feeling a wide open window to the music, like the Headphonia, Hornet, and the PRII.

The XM4 is really a fun listen. It lacks that OVERALL “WOW” factor that the best amps have, but it’s a very enjoyable amp, with no major faults that detract from its overall performance. Price versus performance and features also make it right up there with the Headphonia for bargains.

> T+D Dreamwork Xtra X-1

Well, this amp, unfortunately, fell out of the review. I had included it in the informal review sessions, but when I started the formal review, the amp stopped working. It makes noise and does not play music. I contacted the Ebay seller who immediately offered to replace it, so I will be doing that, but it really can’t be included in this review or ranked. I will say that I found the amp pleasant to listen to, but distinctly warm and not all that neutral. Pleasant, but not transparent enough for my tastes. But anyway, that really is all I can say since who knows if the one I bought ever worked correctly.

UPDATE 1/24/07:

After several weeks of turn-around time (mostly shipping related), my X-1 is back. The new one works fine. After a little break in, it sounds the same as the first one, if memory serves me. In any case, here are my thoughts on it:

Build Quality: B+: Nice metal case. In general the build quality is good, and if my first sample hadn't failed, then I'd give it an A-. Only a small turn-on/off thump, and very little hiss.
Treble: B+: some veil and grain, and the low treble is a little spitty. Lacks air and extension. I'd describe the treble as "dark". Not bad, but not great.
Midrange: A-: pleasant sounding, VERY warm and lush - almost fat. Has a tube-like sonic quality. This is the main signature of this amp - you'll either love it or hate it...it's not strictly accurate.
Bass: A-: Deep, and powerful, and reasonably well defined – a bit fat on the upper bass.
Neutrality: B: I don't think that this is a neutral amp. It sounds very pleasant, but it's not neutral.
Soundstaging: A-: Good mix of depth and width. Nice in general.
Transparency: B+: The sonic signature of the amp is nice but really doesn't give a completely transparent presentation

This amp provides good value for the money, and has a sonic signature some will love.

UPDATE 2/2/07:

I am adding some amps that I have purchased (and in one case was loaned by another head-fier)/ These amps are the Xenos 1-HA-EPC, the iBasso P1, and the Headamp AE-1.

> Xenos 1HA-EPC

Info: http://www.aptecpro.com/products.html

The 1HA-EPC is large and heavy for a portable amp - right up there with the PRII in size. It has a built in rechargeable battery, a gain switch, and a nice crossfeed circuit. My EPC version is the higher-end of the 2 1HA's, with discrete output devices

Build Quality: A-: Nice metal case. Not designed for glitz, but superb construction.
Treble: A-: Open and transparent. Lacks ultimate air and extension, but only a little. Plenty of detail. Smooth and inviting.
Midrange: A-: pleasant sounding, warm and lush, transparent, smooth, and again, inviting.
Bass: A: Deep, tight, powerful, and well defined - no doubt a strong suit. Excellent bass performance.
Neutrality: A-: except as noted above, generally neutral amp but the tiniest bit dark.
Soundstaging: A: Very good, and with crossfeed truly excellent.
Transparency: A: Right up there with the best in this regard – has that “wow” factor of feeling a wide open window to the music, like the Headphonia, Hornet, and the PRII.

The Xenos is a terrific amp. I am totally entralled with its sound. It's a tiny bit dark or mellow, but not overly so, and it has just a wonderfully engaging sound. And certainly has that "wow" threshold. GREAT value too - among the best I have heard, it's alongside the Headphonia as the least expensive in that category.

I have a very hard time deciding whether the 1HA is better than the RSA Tomahawk or not. Both are truly excellent. The TH is a little more exciting, but the 1HA is a little more engaging - "cozier" if you will than the TH, which is a little brighter. In the end, I have spent considerable time swithcing between the two, and they are different enough, I have decided to rank them evenly.

> iBasso P-1

(No current website)

The iBasso P-1 is a medium sized portable amp - the same size as the Headphonia, but in a MUCH nicer metal case with a glossy finish. It's very classy looking - among the nicest. It has built in rechargeable batteries with a charge indicator around back, but it's featureless otherwise. It comes with a wonderful interconnect that could probably be sold for half of the amps $99 asking price.

Build Quality: A: Very attractive and solidly built - top shelf.
Treble: B+ : A little bit brittle - slightly grainy - a touch of edge. But good extension and decent top-end air.
Midrange: A-: a little bit too forward sounding on occasion, but generally clean and open. Certainly good performance.
Bass: B+: A tiny bit unrefined, and not top shelf power. But generally good bass performance, with decent punch.
Neutrality: A-: except as noted above, generally neutral amp but the tiniest bit dark.
Soundstaging: B+: decently deep, nicely wide - good overall.
Transparency: B+: It's not as open sounding as I like - it's a bit veiled overall compared to the better amps.

The iBasso is a very good value for the money. It's a nice sounding amp. It doesn't challenge the very best, but it overall really provides an enjoyable experience for the small $99 asking price. Easy to recommend at this price.

> Headamp AE-1

HeadAmp - Audio Electronics (Portable Headphone Amplifiers)

Another head-fier was kind enough to offer to send me his AE-1 to listen to. I have no idea if it represents current production or not, but the AE-1 is a current amp from Headamp. It's incredibly nice to look at - very well built. It's the same size as the iBasso or Headphonia. Built in rechargeable battery, and has RCA inputs on back in addition to the mini-jack input on the front.

Build Quality: A: Very attractive and solidly built - maybe only exceeded by the PRII.
Treble: A-: Smooth, silky, open, clean, and detailed. But only good extension and missing the very top-end.
Midrange: A-: Smooth and open sounding. Very open, even, and inviting, never aggressive. Lush.
Bass: B+: Tightwell defined, with decent punch. But a little too lean for my tastes.
Neutrality: A-: excellent from 100Hz to 8kHz or so, but a little rolled off at the extremes.
Soundstaging: A-: Great width, decent depth. Very convincing image.
Transparency: A-: Open sounding to be sure. Not veiled. Not THE best, but up there.

The AE-1 is a very good sounding amp. It's incredibly well built. But it's not as good as the Xenos 1HA, and maybe on par with the Headphonia sonically, which are both less expensive (although it's nicer to look at). It certainly is in that category of amps that produces a "WOW" listening factor.

A couple more photos:

> Portaphile V2^2


I was asked to review a fully-burned in Portaphile V2^2 by its maker. So I did.

Build Quality: A-: It’s an attractive, well built amp. I’m not wild about the toggle on/off switch, or the length of the volume knob, but it’s still a solid amp. Slight turn on “click”.
Treble: A-: Smooth, open, clear, and reasonably detailed. But just a touch laid back/soft, and missing the very top-end extension.
Midrange: B+: Slightly dry. Clean, but dry. The RSA TH was notably lusher.
Bass: A: Punchy, deep, powerful. Good definition. A strong suit. A real bass-lover’s amp. Only the Hornet, PRII mk 2, and Xenos 1HA are better.
Neutrality: B+: Decent, but sort of downward-sloping response, which isn’t strictly neutral.
Soundstaging: B+: very good width, fair depth. Not a limitation but not a strength either..
Transparency: B+: No real grain, but just not that clear, open window on the sound that the better amps have. Close, but not quite.

The V2^2 is a competent amp, and it sounds good. But it wasn’t for me as good as either the Headphonia or the Xenos 1HA, which are in its price class. So for me, that makes the Portaphile, which is a basic amp with no real “features”, kind of a tough sell.

UPDATE 3/30/07: I now have more than 400 hours on the Portaphile. It has improved some, no doubt. It's a very good amp. I still prefer the Xenos 1HA-EPC, but I prefer the Portaphile to many other amps, and especially recommend it to people who want some real bass punch. After 400 hours the treble is improved, and if anything, the bass is even better! Its really a very good amp. I didn't move it in rank, as I still feel it is where it belongs in the ranking, but I feel better about recommending it, for those who have the patience to break it in for 400 hours!

> Xenos 0HA-REP


I was asked by ATP Systems to review the newer 0HA-REP. So I did. It looks the same, but is a different amp internally in many ways I am told, and now has a battery charging feature, a feature that I essentially demand from a portable amp.

Build Quality: B+: No amp made of plastic gets more than a B+ from me, but it’s an attractive, well built amp. Slight turn on “thump”. Hiss becomes noticeable at 12:00 on the volume control – this isn’t a very quiet amp.
Treble: B: Slightly edgy, overemphasized, and “spitty” Somewhat grainy.
Midrange: B+: Decent performance here. Even. Not super engaging, but no real problems.
Bass: A-: Still this amp’s strong suit IMO – punchy, powerful, good definition.
Neutrality: B+: Would be better if the treble were smoother.
Soundstaging: B: Good depth, fair width. Again here, not a limitation but not a strength either.
Transparency: B-: A bit of grain, Sort of opaque sounding.

The 0HA-REP is better than the original 0HA – I was able to compare them directly. And for a $99 amp, it’s good – bettered only by the iBasso P1 in that price class.

> C&C Box V2

(no current website)

This amp has a lot of features – a low frequency boost, a midrange boost, and some sort of soundfield enhancer. The C&C Box can, as a result, be made to have a variety of different sonic signatures. Unfortunately, none of them is really neutral, as we’ll see.

Build Quality: A-: Very nice metal case. The raised LED is a bit too close to the jacks for some plugs. Slight turn on thump. Slight turn on “thump”. Hiss becomes noticeable at 11:00 on the volume control – this isn’t a very quiet amp.
Treble: B-: Grainy and etched. Almost annoying.
Midrange: B-: It just doesn’t sound right – there is a nasally coloration when the “MF” switch is off, and when it’s on, the sound is way too strong in the lower mids. The use of the switch maybe compromised the design.
Bass: A-: A little muddy, but strong and punchy – good bass performance.
Neutrality: B-: None of the settings, including all flat, provided a neutral sound.
Soundstaging: B: Good depth, fair width. Decent performance.
Transparency: B-: It just isn’t very transparent.

The C&C Box simply did not impress me. The ibasso P1 is much better for a little less money, and the Xenos 0HA-REP is better for the same money. Going from the C&C Box directly to the SR71 drove home the huge difference there is in the performance of portable amps. It was startling. Because you can really make the C&C Box have a variety of sounds using its switches, this amp will likely appeal to people who are looking for a certain “sound”. I am just not one of those people.

> iBasso T1

(no current website)

I was asked by the importer of this amp to review it. So I did. It’s stunningly small, and VERY attractive. The most retail-oriented headphone amp I have seen. It has 2 headphone outs, and a nice bass boost switch.

Build Quality: B+: Tiny. Pretty. Solid for the size. The switches are a little cheesy, though..
Treble: B+: Pretty amazingly clean. I was surprised. Not the most extended, but enjoyable.
Midrange: B+: Again, decent but not exceptional performance, but no real “problems”.
Bass: B+: Not the world’s most defined bass, but enjoyable.
Neutrality: A-: Pretty even sound. Remarkably so, actually.
Soundstaging: B: Just OK here..
Transparency: B+: No real grain. Surprisingly open.

The iBasso T1 sounds incredible for the size – it’s smaller even than the RSA Tomahawk. And regardless of size, it sounds good for the money, although it’s been selling on EBay for the same price as the same company’s own P1, which is the better sounding amp. So you do give up some sound for packaging. Still, a nice little amp

> Ray Samuels Audio SR71


I had always been interested in this amp, so I finally broke down and bought one. I am glad I did. I don’t miss my Hornet anymore.

Build Quality: A: The best there is, physically. The Larocco PRII mk 2 may be a tiny bit prettier, but the SR71 is better built, and very attractive. It is slightly noisier than the Hornet, however – probably due to more gain. Also has a slight turn on thump, which the other RSA amps didn’t.
Treble: A: Smooth, extended, open, clean, and detailed. Truly excellent.
Midrange: A: Smooth and open sounding. Very open, even, and inviting, never aggressive. No glare at all – the Hornet had just a touch of upper midrange glare, the SR71 does not, making it the better amp in the mids IMO.
Bass: A-: Defined, full, and fairly robust, but slightly less of it than I’d ideally like, esp. versus the PRII mk 2 and the Xenos 1HA-EPC. But just a slight bit less.
Neutrality: A-: terrifically neutral except missing that one tiny bit of bass, and many people may actually prefer this bass balance.
Soundstaging: A: Great depth, excellent. Very convincing imaging – excellent performance here..
Transparency: A: Wide open, clear, engaging sound.

The RSA SR71 immediately impresses with that “WOW” factor. It’s a fantastic amp. It’s kind of big, and I wish it had a batter charger. But in comparing, it clearly betters the Tomahawk. I wish I still had the Hornet to compare directly, but if memory serves me, the SR71 is a tiny bit better everywhere other than the bass, and likely just a little better overall.

Update 3/30/07

> Storm B-4

(No web site that I know of – in the USA can be purchased for $250 from EBay member jasmine_chine whi imports them, email zhounk@hotmail.com).

I bought one of these from Jasmine_chine. I bought it direct, not via EBay, and it was a totally smooth transaction. This same EBay seller sells iBasso amps on EBay.

Since this amp isn’t well known and there is no web site, you can look at the EBay ad for pics and specs Here

Build Quality: A-: It’s a very attractive, solid, well built amp. The volume control has a kind of scratchy feel to it, but it does not make audible noise through headphones when turned. I would give it a full A for build quality if not for that. Slight turn on “click”.
Treble: A-: The treble is very natural. There is just a hint of grain. I wouldn’t want any more treble energy, and with bright cans it might not be a great match. But in general the treble is extended and clean.
Midrange: A-: No one will confuse this for a tube amp, but the mids are open, clean, and natural. There is a very slight lack of transparency, but again performance is good.
Bass: A-: Not world class, but the bass is nonetheless very good. Good definition, speed, and clarity, and enough punch for everyone but the worst bass freaks.
Neutrality: A-: Very even sound – no real issues here..
Soundstaging: B+: Very good width, good depth. Again, not world-class, but better than most.
Transparency: B+: It doesn’t sound as open as the very best amps, but here again it is better than most. It isn’t as transparent as the RSA or Larocco amps, but its darned good.

The Storm B4 is a very well built amp that sounds very good. It ranks up in the top half of the amps I have heard. I think it would be a no-brainer recommendation at $200. At $250 it’s a little tougher. I slightly prefer the sound of the Xenos 1HA-EPC, although it’s bigger and heavier than the Storm. I also like the RSA Tomahawk better sonically, but the Storm has a built-in Ni-MH battery and comes with a charger. So in the end, this is a very nice amp, but in a price range where the competition is very tough.

UPDATE 4/14/07:

> Xin SuperMicro IV

Xin's Cool Talk - New XIN amps with 4-channel technology

I was asked to review a SuperMicroIV by Nfusion770. So I did.

First of all, let’s talk about form factor. The SuperMicroIV looks like it was built into a piece of lego. It actually made me laugh. Its sound quality though, is no joke. It’s a seriously good amp.

Build Quality: B-: The nicest thing I can say about the build quality is it’s functional enough, I suppose. But this amp has ZERO style points. I doubt it would ever really be possible to break it, but you could easily move it wrong and have the lid and battery come flying out. It’s pretty hard to take the amp seriously based on its physical being. Sonically, however….
Treble: A: Smooth, open, clear, and detailed without being the least bit harsh or etched. Transparent, smooth, and neutral. Truly among the best. I was surprised.
Midrange: A: Smooth, open, and jaw-droppingly transparent. How does he do it? The mids are completely neutral. Impressive as hell.
Bass: A-: Punchy, deep, powerful. Good pitch , attach, and definition. Not the bassiest amp there is to be sure, but in no way lacking.
Neutrality: A: this amp is utterly neutral.
Soundstaging: A-: soundstage width is excellent, depth is just short of the best.
Transparency: A: Really amazingly transparent. Certainly feels like a wide-open window on the music. The WOW factor is there in spades.

When you LOOK at the SuperMicro, you’d say “I paid $170 for this? What a rip off!”. But when you LISTEN to the SuperMicro, you’ll say “I can’t believe this thing was only $170”. It sounds that good.

Buyer beware: Xin is a frustrating company to buy from. I have never, ever heard of someone who in the end didn’t get their amp, and Xin allows payment by credit card where he does not charge you until he ships, so he’s better than Larocco Audio in that respect. But based on my experience with the SuperMicroIV (and my prior experience with the SuperMacroIII and IV), I understand why people will put up with the wait. This is a great amp.

> Xtra X-1 Pro

(No website that I am aware of; can be ordered from EBay seller Jasmine_Chine, which is where I bought mine)

My experience with the original X-1 was mixed. I thought it sounded pretty good, but my first one failed. The second worked fine, and had a very definite character which I thought some would love and some might not.

The X-1 Pro also has a specific character, but not the same as I recall the original X-1 having (although I did not have it around to compare directly with).

Build Quality: B+: Externally 100% identical to the original X-1, as best I can tell. Small; nice enough metal case. Aside from built in battery, zero features. AC charger requires adapter to be used in the US. Loud turn on pop, but the amp had ZERO hiss – very quiet.
Treble: A-: Smooth and grainless. On the edge of bright. But pretty transparent.
Midrange: B+: Very forward sounding mids. Transparent enough, but they will not suit every headphone. The Sennheiser HD25-1 was not a good match. However, it was a great match for the Beyer DT770, and in fact may be my new recommendation for DT770 users who want a portable amp that will bring the mids up a bit. Careful headphone matching will be key here.
Bass: B+: Maybe it’s the jacked up mids, but the bass seems a bit lacking in quantity. Bass quality was good, though, with, good definition.
Neutrality: B+: Would be better if the mids were less pronounced and the whole spectrum a bit smoother. But again, this will be great for some headphones.
Soundstaging: A-: excellent depth, good width. The soundstaging was convincing.
Transparency: B+: Basically transparent, although not among the very best here.

The X-1 Pro is not the warm, fat sounding amp I found the original amp to be, but it’s not completely neutral, either. Its forward mids will excite and thrill some, and will be a good match with come headphones. With others it will make the sound too aggressive and painful. Careful headphone matching will be key.

> C&C XO

Headb.com: C&C XO portable headphone amplifier

The new C&C amp, the XO, is drop-deap gorgeous. Mine is purple, and beautiful. It comes with a nice leather wrap, and a nice box. Top class all the way. This amp has a lot of features – a low frequency boost, a gain switch, an impedance switch, a soundfield enhancer. I preferred it greatly to the C&C Box V2 sonically was well, although it’s still not going to be everyone’s cup of tea.

Build Quality: A-: Very nice metal case. Very pretty. Slight turn on thump but no big deal. Not the beefiest thing in some ways, but elegant.
Treble: B+: Treble is smooth and silky. Lacks ultimate top end extension and air, though. Relaxed and non-fatiguing.
Midrange: A-: It’s very laid back and warm. Clean and smooth, and not at all forward. Maybe a little too much so, but it does have almost a tube-like charm.
Bass: A-: Strong and punchy – good bass performance. Good detail and attack.
Neutrality: B+: It isn’t really neutral, but it sure is pleasant. Warm and friendly. Invitingly relaxed sound, and was a very good match for the HD25-1’s.
Soundstaging: B+: Good depth, fair width. The soundfield processor was actually pretty effective, although it does have some impact on frequency response.
Transparency:B+-: Pretty transparent sound. Not among the very best, but not really an issue..

The C&C XO is a very pretty looking, and very pretty sounding amp. It’s funny how much this amp’s sound matches its looks (versus the Xin where they are polar opposites). It’s also funny that it’s sort of the opposite sound of the new Xtra X-1 as well. The C&C Box V2 did not impress me. But I really like the XO. It’s very easy to recommend for a relaxed sounding, almost tubey amp, that will certainly attract compliments from anyone who sees it.

Update 4/23/07

> Meier Audio Porta Corda III

Kein Titel

GreatDane was nice enough to lend me a Meier Porta Corda Mk III to review. The PCIII is large-ish for a portable amp – longer than a SR71, but a little shorter, and since it’s in a plastic case, it’s lighter than the SR71. I am not a fan of the PCIII’s industrial design – it isn’t going to win any beauty contests, that’s for sure. But I am not reviewing these things for looks, so how is the sound? In a word, great. It’s definitely in that top tier of amps that make me go “WOW this sounds good!”.

Build Quality: B+: Here again, the amp is functional and the case is solid enough, but it’s not pretty at all. Connectors are all above-average solid, though, so it gets some points back for that.
Treble: A: Treble is amazingly clear. Smooth, open, liquid, and detailed ZERO grain. Highly transparent, and neutral. Shares this with its big brother home amps. Great air. Maybe lacks that very last bit of extension that the Larocco amp has, though.
Midrange: A: Here again, very open, smooth grain-free, transparent sound. Talk about an open window to the music! This is the kind of midrange performance that we live for.
Bass: A-: Excels in pitch, attach, and definition. It doesn’t have quite the punch of an RSA amp in this regard, however.
Neutrality: A-: Neutral except for the very slight lack of bass weight.
Soundstaging: A-: soundstage width is excellent, depth is just short of the best. Image specificity is very good. A couple of times I actually turned my head to “listen” for a sound!
Transparency: A: This is a strong suit to be sure – Meier amps are jaw-droppingly transparent.

So the PCIII is not just a great amp, but with it’s $160USD price, it’s an incredible value, and it has to be that it and the Xin SuperMicroIV are the two best VALUE portable amps I have ever heard. I cannot imagine better sound for less. If you can deal with the pedestrian looks, this amp rewards with way above price-class sound.

Update 5-19-07

> Go-Vibe V6

Info: www.go-vibe-headphoneamp.com coming soon!

I was leant a Go-Vibe 6 by very kind head-fier Goodsound. This version has the AD8620 op-amp. As such, I added the following to my review and update the rankings. This updated Go-Vibe is nicer looking and seems better built than the GV-5. It also sounds better! Quite a lot better. I wasn't impressed with the GV-5. The GV-6 sounds better, and I feel is a good deal for the money. It's not perfect, but what is?

Build Quality: A-: It’s got a nice black anodized Hammond metal case. Feels very solid. No turn on thump at all. Fairly quiet -the amp exhibits very little noise at all.
Treble: B+: I did not care for the GV5’s treble presentation at all. The GV-6 has a better treble, but it is still, IMO, the amp's weak point. The treble is a little grainy, and lacks air and extension. But it's a big improvement over the GV-5, and isn't too bad.
Midrange: B+: generally smooth and clean, much more forward than the GV-5. In fact, more forward than the Tomahawk! It's a somewhat forward midrange now. Not unpleasant though, and fairly open sounding, although not up there with the best.
Bass: B+: punchy sounding, but lacks deep bass power. Stronger mid-bass. Decent definition and attack.
Neutrality: B+: has a kind of tube-like sonic signature. Stronger lower treble than upper treble, slightly fat midrange and mid-bass, and not strong deep bass.
Soundstaging: B+: good depth, decent width. Not stellar, not bad.
Transparency: B+: Generally transparent except for the treble, where I felt it was a little murky. But decent.

Hmmmm...all B+'s. Overall, the Go-Vibe 5 wasn’t my cup of tea, and while the GV-6 is much better, it still isn't 100% my cup of tea, although some will love it, since it's got a definite "sound" - again, one I feel is sort of like a tube amp. For me, the RSA Tomahawk and the Larocco PRII mk 2 which I directly comapred it to, are immediately noticably smoother and more open and transparent. But they are 3-5x the price of the GV-6! For the money, I think the GV-6 is an excellent amp. It's awesome you can get an amp this good for this amount of money. And while in this price range I prefer the iBasso P1, the GV-6 is far more tubey sounding than the iBasso, which will make it a better match for some headphone and head-fiers.

Update 6-7-07

> mSeed Labs Spirit

Info: Spirit AMP Portable Headphone Amplifier with Blackgate and Class A Biasing

I was leant a Spirit amp from MSeed labs by the manufacturer. See the above link for a full description, but this is a serious portable amp – Black Gate caps, JFET op amps biased into class A. I think the “plug in” board for use with an AC adapter is a little odd, but at least there is a way to use an AC adapter. No charging circuit though, which is a small bummer.

Build Quality: A-: It’s got a nice black anodized Hammond metal case. Jacks are very solid. No turn on thump at all. Fairly quiet -the amp exhibits very little noise at all.
Treble: A-: Treble is smooth, detailed, and uncolored. It was bright at first, but after break in for 200 hours it wasn’t. Excellent treble.
Midrange: B+: Open and enjoyable. Nice and neutral. Not lush or rich, but not thin. The very best amps are better, but the mids are enjoyable - not a liability.
Bass: B+: Great definition and depth. Not super-punchy and not the meatiest bass around, but very tight. Great pace and rhythm to the bass.
Neutrality: A-: Superbly neutral; only detraction is the ever so slightly lean bass. But this is NOT a colored sounding amp, as so many portable amps under $200 seem to be.
Soundstaging: B+: good depth, decent width. Good image specificity. Again, not the best ever, but not a liability.
Transparency: A-: Above average transparency. Excellent performance here.

The Spirit is a VERY good amp, and for the money it’s outstanding. I really liked it - I was very impressed. It ranks in the upper tier of amps, and it represents good value. If it were in sexy case it could sell for $300, but let’s not tell mSeed that .

Update 7/9/07

> Meier Audio MOVE

Kein Titel

I have always liked Meier amps, so I was anxious to get my hands on a MOVE. My main beef with the Porta Corda was it's very DIY looks. It sounded very good (although I did find it slightly lean).

After breaking in the MOVE for 100 hours, I listened to it a LOT before writing this - much more so than many other amps I have reviewed. I used a bunch of different headphones. Why? I wanted to be sure of what I was going to say, because there will be some people who are going to get their panties in a wad about this review.

I think the Meier MOVE is a phenomenal headphone amp. Stunningly good. Better than any amp in this review aside from the Larocco PRII, and in some ways better than it. It combines a natural, warm sound with incredible detail, an outstanding soundstage, and very extended frequency extremes. It's also built like a tank, is very well featured, and is bargain priced. It's impossible not to recommend with great enthusiasm.

Build Quality: A: Awesome metal case. I'm certain it could survive being thrown against a wall at high velocity, although it's so pretty you wouldn't want to. I'd give it an A+ except for one thing - the volume knob, while attractive, is very difficult to grip, and thus hard to turn. It's my one complaint about this amp.
Treble: A+: Treble is amazingly clear. Smooth, open, liquid, and detailed ZERO grain. Highly transparent, and neutral. Very much like other Meier amps. Great extension and air. I doubt there has ever been a portable amp with better treble than this.
Midrange: A: Beautiful, wide open sound. Inviting, clean, open, and engaging. Grain-free. Just gorgeous.
Bass: A+: Excels in pitch, attach, and definition. Also punchy as heck. ZERO bloat or boom, but great weight.
Neutrality: A: There are simply no issues here - very, very impressive.
Soundstaging: A: soundstage width is excellent, depth is just short of the best. Image specificity is very good. The soundstage is top-shelf.
Transparency: A: This is a strong suit to be sure – all Meier amps I have ever heard are jaw-droppingly transparent, and the MOVE is no exception. I was prepared for it not to be, since there was some talk that the choice of op-amp wasn't going to mean a transparent sound. That isn't the case. It's very transparent.

So now we have a terrific Meier portable amp that also looks nice. I preferred the sound in high current but low gain mode. Basically noiseless in this mode. Dynamic, lush, detailed - it's hard not to gush. I listened over and over again to it to be sure - I am sure. The MOVE is the best bargain in portable headphone amps right now on the market, based on all that I have heard.

Update 7/16/07

> Headamp AE-2

HeadAmp - Audio Electronics (Portable Headphone Amplifiers)

Another head-fier was kind enough to offer to send me his AE-2 to listen to. Like the AE-1, it's incredibly nice to look at - very well built, and really beautiful. Really only the Larocco is as nice looking as the AE-2. Built in rechargeable battery, and has RCA inputs on back in addition to the mini-jack input on the front. I did not have the AE-1 to compare to it directly, and from memory I think it’s an improvement to what was already a very good amp.

Build Quality: A+: Outstanding build quality. Very attractive and solidly built - maybe only exceeded by the PRII.
Treble: A: Smooth, silky, open, clean, and detailed. . Much better than the AE-1 in this regard. On par with the Meier and RSA amps in this regard.
Midrange: A-: Smooth and open sounding. Very open, even, and inviting, never aggressive. Not as lush as the mids were on the AE-1 I’m pretty sure. .
Bass: B+: Tight, well defined, with decent punch. But a little too lean for my tastes. This just isn’t a bass-lover’s amp. The bass that is there is very good, but it lacks enough bass weight and authority IMO.
Neutrality: A-: The above lack of bass weight makes it just short of the best amps here – it’s sometimes just a little bright sounding without the bass foundation. But this is only when directly compared to the Meier or RSA amps.
Soundstaging: A: Excellent – very good, outstanding depth. Very convincing image – excellent specificity. .
Transparency: A-: Clean and smooth. Not *quite* at the same level as the Meier or RSA amps, but very close.

The AE-2 is an excellent sounding amp. It's incredibly well built. It certainly is in that category of amps that produces a "WOW" listening factor. Plenty of gain – drove 250 and 600 ohm headphones without difficulty. You do get a built in rechargeable battery, and a charger, as well as nice looking amp. But it’s more expensive than several amps I think sound a little better. This means you have to really value the way it looks, or prefer an amp that has a littler less bass, to have the AE-2 make sense financially. Otherwise, I’d buy a Xin SuperMicro, Meier Move, Xenos 1HA, or RSA Tomahawk.

> iBasso T2


I was asked by the importer of this amp to review it. So I did. It’s stunningly small, and VERY attractive. The most retail-oriented headphone amp I have seen. It has 2 headphone outs, and a bass boost switch, as well as a sort of a crossfeed switch. Built in rechargeable battery and charger. You get a lot for your money! And it and it’s brother the T1 are s the smallest portable amps around. Perfect mate for a iPod Nano for a super-small, super good portable rig.

Build Quality: B+: Like the T1, small and attractive, and pretty solid for the size. The switches are a little cheesy, though.
Treble: B+: Reasonably clean and detailed, but somewhat rolled off.
Midrange: B: A little cloudy and opaque sounding. Seems like the designer wanted a tube-like sound. A little nasally.
Bass: B+: Upper bass a little forward and deep bass is slightly lacking. Bass weight is very good.
Neutrality: B: Lacking a little in the frequency extremes, and a little goosed in the lower mids/upper bass.
Soundstaging: B+: Decent. Width is very good, depth is decent, image specificity is decent.
Transparency: B: No real grain. But the slightly cloudy mids detract a little.

It seems that iBasso was looking for a different sound than the T1 offered. I no longer have the T1 around, but compared to the amps I do have around, the T2 isn’t really all that neutral sounding. It seems that they wanted to make it sound kind of like a tube amp, much like the C&C XO. This will appeal to lots of people, probably. And I’m sure my ranking is going to rankle some people who do seem to really like the T2’s sound. But it doesn’t really light my fire, I have to confess. I prefer a more neutral sounding amp. It does sound better with headphones that are slightly bright like the AT ES7. And for the size and cost, it’s a truly unique amp that will appeal to lots of people I’m sure.

Update 8-5-07

> MicroShar uAmp107

Info: Microshar.com

I was leant a Microshar uAmp107 by the manufacturer. See the above link for a full description. The “list” price of the amp is $135, but it seems to be on sale a lot . It features an interesting turn-on function in that it powers itself on when both the input jack and headphones are connected. Sounds cool, except for the fairly loud click that occurs when it powers up, that you can only avoid by not having your headphones on/in.

The amp’s built in battery lasts FOREVER – I never really did fully run it down, in spite of using it over 100 hours to break in the amp TWICE. Very cool. Comes with a charger.

Build Quality: B: sturdy but cheap-looking plastic case. The amp also has sone audible hiss at all volume levels with low-impedance headphones, even the 70-ohm HD25-1’s. And there’s that turn-on click.
Treble: B+: Treble is detailed, with a slight bite/edge, but it’s clean. Lacks the very top end extension, but what’s there isn’t overly-laid back, so it doesn’t seem closed-in.
Midrange: B+: Open and enjoyable. Nice and neutral. Slightly forward. It makes it seem exciting at first, but in the end I prefer the slightly lusher midrange of the Meier Move or the mSeed Spirit. However, the mids are very enjoyable on their own terms..
Bass: A-: Good definition and depth. Not the tightest ever, but nice and punchy. Very enjoyable bass.. Great pace and rhythm.
Neutrality: A-: Nicely neutral; only detraction is the ever so slightly forward mids. But this is NOT a colored sounding amp, as so many portable amps under $200 seem to be.
Soundstaging: A-: Very good depth, good width. Very good image specificity. Quite enjoyable SS presentation.
Transparency: B+: It loses points here for the hiss. Otherwise quite good..

The uAmp is a very good amp. For $135, it’s tempting to recommend the mSeed Spirit instead, which I slightly prefer. But for the $85 that it’s currently listed as being available for on the Microshar website, it’s a ridiculous screaming bargain and everyone should go buy one to throw in their briefcase just for the wicked-long battery life! A very nice sounding little amp, that has a few rough spots, but whose overall performance hits way above it’s price class.

Update 9-16-07  [NOTE: the newer version Trian Audio L3 review is here ]

Triad Audio Lisa III

Info: Welcome to TriadAudio.net

Surprisingly to me, a lot of people have asked me to include the Lisa III in this review. This is in spite of several things:

1. It's far more expensive than all but the Larocco PRII;
2. It's big enough that it really stretches the limit of what can be considered a "portable", in spite of it being battery powered;
3. I've already reviewed it here; and
4. It should be pretty clear that it would be number one, taking the above into consideration.

But nonetheless, I've been asked enough that I have decided to do it.

Build Quality: A-: Well built in a nice metal hammond case. Nice faceplate and knobs. LOVE having RCA jacks, but would have preferred hacing a mini-jack in parallel. Not quite quiet enough for IEM use without an impedance adapter. It should come with a power supply at this price, especially since it uses internal rechargeable batteries, and gets a modest 5-6 hours on a single charge.
Treble: A+: Oh, those highs. SOOOO very clean, extended, airy, sweet, detailed...the treble is so much better than most portable amps. Only RSA amps, Meier Move and the PRII are in the same league. And I'd say the extension and airiness is even better on the LisaIII than any of these. Not night-and-day better, mind you, but better..
Midrange: A+: The midrange is open, lush, inviting, and very transparent. It's not the least bit too aggressive, but it isn't at all recessed either. I guess that makes it neutral, but not in a sterile way - it's "good neutral". If anything, perhaps it's just a touch warm. That's a good way to be.
Bass: A+: The bass is of course quite tailorable in terms of quantity, due to the bass countour knob, but the quality is excellent - it's well defined, tight, and has good "speed" of attack. And it's as deep as your headphones can muster, to be sure. And that control knob means you can have as much of it as you want. For my Denon D5000's it was best left off. For Sennheiser HD580's, though, I liked the bass control at about 1/3 "on".. Great pace and rhythm.
Neutrality: A+: Supurbly neutral, but not analytical or cold. Just plain old not colored.
Soundstaging: A: The soundstage is also exceptionally good -- nicely deep, wide, and fleshed out. It isn't light years ahead of other amps here, but it's still great.
Transparency: A+: I do not hear any way in which the Lisa III isn't transparent. WIDE open window to the music.

OK, so it's great. Really. If you can accommodate it's size and weight, can live with 5-6 hours run time between charges (this will be improved in future versions to 10 hours I hear), and can afford it's asking price, it's a no brainer. Those are some significant ifs when it comes to a portable amp, but if you are concerned solely with sound, the Lisa III is the way to go, no doubt.

Update 10-5-07

Leckerton Audio UHA-3

Info: [URL=http://www.leckertonaudio.com/[/URL]

The UHA-3 was loaned to me by it's maker, at my request. It's got a USB DAC, which I will comment on elsewhere, but which I will say here works very well and sounds very similar to the analog input performance which I detail here.

Build Quality: A: Well built in a nice metal hammond case. Nice faceplate and knobs. Batteries recharge with the USB connection, very nice way to go! Power switch on the rear, separate from the volume knob is also very nice IMO. Well built little amp..
Treble: A-: Nice, sweet, grainless, and clean, but slightly laid back. Lacks ultimate air and extension, but still very enjoyable. This may be what makes the soundstage seem slightly small, though.
Midrange: A-: The midrange is open, lush, inviting, and nicely transparent, although not quite as much so as the top amps here. It's not the least bit too aggressive, but it is just a tad warm of neutral. Still, here again, very enjoyable presentation.
Bass: A+: Bass lover's amp to be sure. Great impact, depth, punch, and definition. Really enjoyed this part of the presentation.
Neutrality: A-: Slightly warmish sound. More so even than the Meier Move, but not so much that the amp sounds colored, just a tad mellow.
Soundstaging: B+: The soundstage is slightly small feeling. Instrument placement and image specificity is good, but it seems like the stage is a little too shallow and a little lacking in width. Still, not bad, and not a fatal flaw at all.
Transparency: A-: Loses just a little for a slight hiss that is present at any volume level, but in general, an open, transparent sound that's very enjoyable.

The battery lasted me over 24 hours on a single charge. The UHA has a lot of nice features, and it sounds VERY good. It's easily worth the asking price, and belongs in the top tier of portable amps. I was really impressed. The quality of current portable amp offerings is stunningly strong, and the UHA-3 is no exception. Nice job to Leckerton Audio.

Update 10/28/07

Visely HEA-1
Info: http://www.visely.com; price $135

The HEA-1 was sent to me by its maker, who asked me to review it. Best I can tell, it’s available for sale only on EBay. It’s made in China.

Build Quality: A: The chassis is a very attractive metal case with a nice faceplate, although it is narrower and taller than some, and as such, mates best with a 1/2G Nano in portable use. Built in battery charging for 9V battery. Run time was decent, about 20 hours per charge. Nice and quiet as well. Well built and attractive amp.
Treble: A: Best part of the amp’s performance. Smooth, detailed, clean, non-fatiguing treble performance. Airy and extended. Really nice treble.
Midrange: A-: A touch of grain slightly sours an otherwise very enjoyable midband. Not edgy or harsh – maybe even laid-back just a tad too much.
Bass: B+: Good bass performance, but not great. Lacks weight and depth compared to the best here. Would not be a match for headphones that also lack bass depth and weight. The rest of the response is smooth enough that the amp doesn’t come off as bright, but better bass would be nice.
Neutrality: A-: Slightly light sound takes a little away from what is generally very good performance here.
Soundstaging: B+: The soundstage is slightly small feeling. Instrument placement and image specificity is good, but it seems like the stage is a little too shallow and a little lacking in width. Good, but not great compared to many other amps.
Transparency: B+: Loses just a little for the touch of grain in the midband. Otherwise actually quite good. I think classical music lovers would LOVE this amp.

So the HEA-1 is a nice amp, no doubt. Since it’s under $140, it’s not got a lot of competition in its price range, and I think it compares well with amps in that range in general. But it’s not a world-beater, and unless it becomes easier to get, it’s going to have a hard time attracting a following.

MiniBox –E
Info: Head-Direct.com price $149

The Mini-Box E was leant to me by Head-Direct, Head-fi sponsor and distributor of this amp. I don’t know where it’s made, but I assume China. Lots of nice features on this amp – bass boost, impedance adjust, soundfield processing of some sort – none of which I used for the review of course.

Build Quality: A: The chassis is a very attractive metal case with a nice faceplate, and it’s nice and small. Built in Li-Ion battery. DEAD quiet operation – totally silent even with the volume at max. Nice. Well built and solid, although I don’t think anyone would describe it as pretty. LOVE the flywheel volume control though.
Treble: A-: Treble is detailed and smooth, but lacks some degree of extension and air, which can make it feel just slightly closed in.
Midrange: A-: A tiny bit laid back, but generally clean and enjoyable. A touch on the warm side of neutral. Generally excellent though.
Bass: A-: Good bass performance, but not great. Lacks a tiny bit of weight and depth compared to the best here, but still very good. Well balanced and punchy.
Neutrality: A: Very neutral except for slightly lacking at the frequency extremes. But balance is this amp’s strongest trait.
Soundstaging: A-: Width and depth very good but short of the very best. Imaging is very good as well.
Transparency: A-: There is just a very slight veil that prevents a higher score here. It’s very good but not equal to the very best.

Probably the very best trait of the MiniBox is that it is very balanced sounding. It’s got no real weaknesses, although it does fall short of the best in several areas. For the money it’s quite good and highly recommendable for the piece.

Go-Vibe 7

No current website

A fellow head-fier leant me the Go-Vibe 7 to listen to. I didn’t plan to review it at first since it was going to be so limited in production, but since the amp will be continued to be produced by another company, I went ahead and did it. And I am glad I did – it’s the best Go-Vibe amp BY FAR.

Build Quality: B+: The chassis is a very plain Hammond case, and the battery rattles around in it. It also hisses at medium to high volume levels, but not enough to really be bothersome. It’s as plain-looking as headphone amps come, but sturdy enough.
Treble: A+: Treble is, in a word, outstanding. Delicate, airy, detailed, extended, smooth – just outstanding. I was shocked.
Midrange: A-: A tiny bit forward, and at times a little congested, but generally clean and enjoyable. The mids were very good but not world-beating.
Bass: A-: Good bass performance, just a tad on the light side. Lacks a tiny bit of weight and depth compared to the best here, but still very good. Well balanced and tight with good definition.
Neutrality: A-: Very neutral except for slightly tilted-up response from bottom to top..
Soundstaging: A: Wide, deep, and well defined. Impressive. Highly enjoyable.
Transparency: A-: The slight midrange congestion is the only limiting factor, but don’t read too much into that – it’s a nicely transparent amp.

So the last Go Vibe is the best, and it’s really good. I hope it stays in production a long time – it deserves to be!

Update 12-5-07

> Qables iQube (Applies to V1 and V2, which have the same amp section - V2 just adds a DAC)

Info: i-Qube - A new dimension in portable hi-fi » home

The iQube is a very interesting amp. It's a class D amplifier topology. This is the first of its kind as far as I know - a class D portable headphone amp. Class D has at least the potential of being more battery-efficient, and I did get almost 100 hours of play on the first set of AAA alkalines I had in it (which I used up in 100 hours of break in). The iQube will charge rechargeables, but it doesn't come with them, nor does it come with a charger, although it has a fairly wide tolerance for AC adapters it would seem.

Build Quality: A+: Excellent, VERY attractive metal case. I wasn't sure at first about having the jack on the back and the volume control on the front, but I loved it in the end. There is a very slight turn-on tick. But overall, the build quality is among the very, very best, and it's the kind of thing that gives great pride of ownership.
Treble: A+: clean, clear, grain-free, extended and transparent. Great air and extension, and very natural. It wasn't too aggressive ever, but it wasn't at all soft or rolled off. I wouldn't use it with super-bright headphones. But this really isn't the iQube doing anything other than being VERY neutral.
Midrange: A: smooth, clean, and open - with amazing see-through type clarity, while being tonally very neutral. There is perhaps just a touch of reticence, but not enough to worry about.
Bass: A: Ultra-deep and powerful, with excellent definition and speed. VERY tight, but not overly generous. Again, Neutral comes to mind.
Neutrality: A+: The new king of Neutrality. Over and over again that's how I thought of it. Easily shows the difference between headphones in a flash. Only the LISA III is in the same league here. While I still love the Meier Move, it has a "sound" moreso than the iQube.
Soundstaging: A-: The soundstage was great, but it wasn't the WORLD's widest. Still, nothing to sneeze at.
Transparency: A: Nothing to take issue with here either. Try as I might to pick up some kind of issue with transparency related to the use of class D, I couldn't. I just loved it.

I have to say, I was HIGHLY impressed by the iQube. Unfortunately for those in the USA, the current dollar>Euro exchange rate makes the iQube pretty expensive -- as of today, it would cost the American buyer over $460, and January 1 it will cost about $500 (at current exchange rates). And as good as it is, I personally don't think it's enough better than the other top amps to easily justify that price here. I know there is nothing Hans at Qables can do about his costs, or the dollar to euro exchange rate, but it is a pity. If this amp could be had in the US for $335, it would be very easy to recommend as the best buy in high-end headphone amps. But it's $335 EUROS. So for everyone in Europe, this is a great amp to get. For those in the US, I think it requires a little more thought. Nonetheless, it's a superlative headphone amp.

Update 1-11-08

> Headamp Pico

Info: [url=http://www.headamp.com/portable_amps/pico/preorders.htm [/url]

I received a loaner of the Headamp Pico from a friend of mine. There was so much interest in this amp, I really wanted to get a chance to listen to one. And I’m not sure of I am glad I did – it’s so good, I now want to buy one! But I need another portable amp like I need a hole in my head.

I listened to the Pico for several hours straight, by itself, and then directly compared it to the iQube and the Meier Move. The Pico had been broken in prior to my receiving it.

Build Quality: A+: What a beauty! Glossy finished metal case, mine in a sort of rust-copper color. By far the prettiest portable headphone amp I have ever seen. Also small and sturdy. TOTALLY quiet operation. Zero turn-on tick. Truly impressive to look at, and it’s the kind of thing that you just WANT when you see it.
Treble: A: clean, delicate, smooth, grain-free, extended and transparent. Perhaps just ever so slightly less top end extension than the LISA or the iQube, but its treble is a DELIGHT. It sounds RIGHT. Never even a HINT of aggressiveness.
Midrange: A+: All I can say here is WOW. The best midrange of any portable headphone amp I have ever heard. I am listening to it now, and just describing it gives me goose-bumps. THIS is tube-like lushness with no opaqueness at all, Yeah, it’s just warm of neutral, but who cares? I could listen to this midrange for the rest of my life and be very happy with it. NICE. If you care about vocal reproduction, especially female vocals, THIS is the portable headphone amp for you. Listening to Kate Havnevik and Imogen Heap on the Pico was an unbelievable treat.
Bass: A: Tuneful, punchy bass. Certainly plenty deep enough. There are amps with slightly more powerful bass, but not by a lot, and the bass quality is excellent. The bass on Tristania’s “World of Glass” was very punchy, but not quite as deep as I get from the iQube.
Neutrality: A: Hmmmm…what to say here. I know the Pico isn’t strictly tonally neutral, but it doesn’t sound colored – it’s just slightly warm/lush. But again, not in a way some amps are that make them sound colored – the Pico sounds like its playing music correctly, so it’s hard to fault its presentation.
Soundstaging: A: The soundstage was VERY deep, and very well defined, but it wasn't the WORLD's widest. That said, the Pico has excellent imaging capabilities – ever so slightly better than the iQube or Meier Move (which I was able to directly compare it to).
Transparency: A: Again, the magic of the Pico is the fact that it’s slightly lush sounding, but still remains highly transparent. This is no easy trick, and many lesser amps have tried this and failed. The Pico pulls it off, and extremely well. Very impressive to me.

What a time we are in – SO many world class portable headphone amps, it’s crazy. The Pico is a huge winner, though. As an FYI, I reviewed the AMP ONLY version, so please don’t ask me how the DAC sounds  I confess I have not been very active reading about the launch of this amp, and I am not sure what the exact production situation with the amp is, in terms of its being readily available. I do know that it sounds fantastic, and combined with its world-class aesthetic design, make it an amp worth seeking out!

Update 1-22-08

> Xin Reference

Info: http://www.fixup.net/talk/topic.asp?TOPIC_ID=2289

I received a loaner of the Xin Reference from another generous head-fier. There has been so much talk about this amp, I really wanted to get a chance to listen to one. I have owned Xin amps in the past, and have always been impressed.

I listened to the Reference for several hours straight, by itself, and then directly compared it to the iQube and the Meier Move. The Reference had been broken in prior to my receiving it.

Build Quality: A: Incredibly solid build quality, with absolutely no nod given to making it pretty. Build like a tank, and looks like one too. I have always wished the Xin knobs were shorter. No turn on thump though, and zero hiss even at full volume. Nice.
Treble: A: smooth, clean, unfatiguing treble, with good detail and extension. Lacks the last little bit of extension and air that the iQube has. Treble performance on par with the Meier Move. Treble was nicely neutral – the difference in the treble presentation of different headphones was easily apparent.
Midrange: A-: Maybe this just a letdown from the outstanding midrange of the Pico, but I felt the Reference’s mids were a little cloudy or opaque. There was a little bit of liquidity missing. This is only in relationship to the very best, but I feel the midrange performance of the Meier Move and the iQube were slightly, but noticeably better than that of the Reference. It’s enough of a coloration that it was apparent with different headphones. This is NOT the high-end amp to buy for lovers of solo piano, jazz quartets, or female vocals.
Bass: A+: Tuneful, punchy bass. Excellent depth, and nice and tight. No bloat. Really nothing to quibble with here. Listening to “Living Together” by Circa Survive, the bass drum impact was palpable. Very nice. Maybe the amps strongsuit?
Neutrality: A: Generally neutral, except for the slight coloration in the midrange. But otherwise very neutral.
Soundstaging: A+: Also a strong suit. The soundstage is deep, wide, and well-defined. There is no “Xinfeed” here, but the amp manages to push the soundstage outside the head in a way the majority of amps do not manage. Excellent.
Transparency: A-: I felt the Xin was behind the best headphone amps in terms of transparency due to the very slight opaque quality of the mids. This is something that someone buying the amp with nothing to compare it to would likely not notice, but compared to the Moce and iQube, it’s there, and IMO it detracts slightly from the otherwise excellent sound. I wanted female vocals to have a little more sense of presence and reality than they did.

So, what to make of the Reference? The mere word “Reference”, and the price of the amp, put it up against string competition. For me, it’s just not impressive enough for the $279 asking price to recommend strongly. I’m sure this will forever vilify me with the Xin-heads, but nonetheless, this is my opinion. The Reference is a very fine amp, to be sure, but I would spend $299 on the amp-only Headamp Pico if it were my money.

UPDATE: 2/24/08

> Meier Audio 2MOVE

Info: Kein Titel

I got a 2Move from Jan on loan to review, but with the advice that I focus mostly on the DAC section, as the amp section was the same as the Move I already own, and had already reviewed. I went ahead and compared the 2Move and the Move, and was unable to tell any difference at all in their amp sections. As such, I am not going to “review” its sound – just look up at the review of the Move. Sonically, they are identical when you use the analog inputs. I will post thoughts on its DAC section elsewhere. The short stroke is that the 2Move’s DAC is much better than the Move’s and makes the amp an even bigger bargain.

A couple of other comments, however. Jan changed mini-jacks from the original Move. Apparently the original Move had some problems with the jacks. Well, just to be a pain, I never had any issue with the jacks on the original Move, and I like them better than the ones on the 2Move. The Battery Door on the 2Move is a HUGE improvement, though, as is the volume knob, which can actually be turned without undue angst 

The Meier 2Move retains its very high ranking in this survey, and I believe it represents the best value for money in all of portable amp land.

> Meier Audio XXS / Headsix

Info: Kein Titel

Jan was kind enough to loan me a XXS, which I really wanted to listen to, since it’s even more affordable than the 2Move, and does not have a DAC, which I don’t need. Unfortunately, the XXS also does not have crossfeed, and I missed that. One of the features I like best with Meier amps is the very well implemented crossfeed circuit. That said, the XXS is much smaller and lighter than the 2Move – it’s Pico/Predator/Tomahawk sized. All these comments would apply to the Meier Headsix, by the way, as the amps are 100% identical, per Jan.

Build Quality: A: Nice, attractive metal case. Looks extremely rugged. The jacks seem to work well, although they require more force to get the plugs in than I would like. Totally silent though – no noise at ALL.
Treble: A+: Treble is extremely clear. Smooth, open, liquid, and detailed, while lacking in any apparent grain. Highly transparent, and neutral – it doesn’t stick out at all. Great extension and air. Equal to the 2Move in this regard. Cymbals are reproduces with the right amount of attack and decay, and they really sound like cymbals.
Midrange: A: Excellent, nicely open mids. Inviting, clean, open, and engaging. Very clean. Just like the 2Move. Excellent with vocals of all kinds, and especially with female vocals.
Bass: A-: To my surprise, the bass was slightly less powerful than the 2Move. While the mids and treble seemed identical to the 2Move, the 2Move has more bass drive. The quality of the bass was very good. Might not be the best choice for bass-shy headphones. Was terrific with the HFI-780, though, which are bassier.
Neutrality: A: What can I say here, other than “its Neutral”. Because it is. Portable amps that color the sound are not a good idea, IMO. Let your headphones color the sound as you like – let your amps give you the music purely. The XXS absolutely does this.
Soundstaging: A: soundstage width is very good, depth is just short of the best. Image specificity is very good. Overall the soundstage is quite impressive for a small, relatively inexpensive amp. I prefer the 2Move with crossfeed on, however.
Transparency: A: You cannot possibly ask for more transparency out of a small portable amp than this. This has always been a big benefit of Meier amps to me. There is NO excuse for lack of transparency in an amp, yet it isn’t easy to do, and many amps don’t get this right. The XXS does.

Well, I kind of thought that I would perhaps ditch my Move in favor of the smaller XXS, since I have no need for a USB DAC. But I won’t be doing that. As good as the XXS is, and it’s amazing for the size and price, the combination of the slightly more robust bass of the Move, and the great crossfeed, mean I will be keeping my Move, and I recommend people spend the extra money for the 2Move if they can. If not, the XXS is an incredible bargain for the money, and will make life VERY hard for many an amp maker.

> Storm B-3

(No web site that I know of – in the USA can be purchased for $220 from EBay).

I was asked by the manufacturer to review this amp. I do not have the original Storm B4 anymore, but the maker indicated that the B3 was better. I really do wish I had the B4 still, because I was pretty impressed with the B4, but not so the B3, I am afraid to say.

Build Quality: A: Better than the original B4 – the volume control doesn’t scratch, and it’s a solidly built, attractively designed amp.
Treble: B: The treble is reasonably neutral. There is a noticeable tough of grain though, AND the amp lacks extension and air. I wouldn’t want any more treble energy, and with bright cans it might not be a great match. But in general the treble is extended and clean.
Midrange: B: The mids are colored. It’s not a strong coloration, but they are colored – there is a slightly “hooty”, oddly recessed quality to them that is immediately noticeable, and for me detracts from the performance.
Bass: B: Good bass quantity, but the bass seems kind of indistinct. Adequate, but nothing to write home about.
Neutrality: B-: Uneven sounding, and somewhat colored. It simply ISN’T neutral. And that’s a problem.
Soundstaging: B: good width, good depth. Average performance here as well – many amps I have heard do better.
Transparency: B-: Every amp I have in house at the moment crushes the B-3 in terms of transparency.

Some B3 owner is sure to say I’m nuts, or that mine is broken. But it isn’t. It works fine, and I put more than 250 hours on it before reviewing it. While the rest of the portable amp universe seems so be moving strongly forward, sadly, that is not the case here. At $220, the Storm B3 is impossible to recommend, and IMO needs to go back to the drawing board.

> Ray Samuels Audio The Predator

Info: News - Ray Samuels Audio

The Predator is Ray Samuels’ AMP/DAC combo. I will have some comments about the DAC section, along with the 2Move’s DAC section, in another thread. Here, we will deal only with The Predator as a headphone amp.
Also, the loaner Predator that HeadphoneAddict was nice enough to send me was fully broken in – more than 1000 hours.

Build Quality: A: Excellent, attractive metal case. Like the other RSA amps, the amp exhibits no noise at all, and I mean zero. Dead quiet – a major plus. Has a 3-position gain selector switch. Slight turn on “click”.
Treble: A: Outstanding. Clean, grain-free, extended and transparent. Lacks the last little bit of treble air that the iQube has, but it has smooth and detailed highs . I cannot imagine anyone having anything but prais for the Predator’s treble reproduction.
Midrange: A: smooth, clean, and open – provides that all-important wide-open window to the music. Classic RSA performance here, which is to say, excellent. One gets the feeling that one could listen endlessly without listener fatigue. Listening to Holly Cole’s “Tango ‘till They’re Sore” was truly a pleasure with the way her voice comes through.
Bass: A+: Terrific bass. WOW. Deep, tight, punch, ample and well defined. Sheesh! Phenomenal. How does such a small amp make bass like this? The double-kick drum on Circa Survive’s “Mandala” was really impressive. Good stuff.
Neutrality: A: A remarkably neutral amp. Not complaints here at all, other than missing the very last bit of treble extension.
Soundstaging: A: Excellent depth and width. Nothing spectacular, but very solid.
Transparency: A: Right up there with the best in this regard – has that “wow” factor of feeling a wide open window to the music. No grain or opaqueness. Very good performance, bettered only by the iQube, and on par with the excellent Meier 2Move.

Given all of RSA’s other excellent portable amps, I really don’t think anyone would buy the Predator unless they needed a USB DAC. But the amp performance is TERRIFIC. Ray knows his stuff.

Update 3-11-08


Info: The Mini³ Portable Stereo Headphone Amplifier *KIT*

The Mini3 is a DIY amp, although it can be purchased complete from a number of sources. Vlad loaned me his completed Mini3 to review. His was nicely built into a small metal Hammond case. There were no features other than a batter charging circuit.

Build Quality: n/a: this will simply depend on how the amp’s builder decides to build it.
Treble: A-: Nice and smooth, and fairly neutral and transparent. Perhaps a bit soft, and lacking the very last bit of top end extension. Still very nice.
Midrange: A: Impressive performance in the mids. Open, inviting, and smooth. I was impressed. Female vocals like Kathleen Edwards and Goldfrapp were very well served by the Mini3’s midrange performance.
Bass: A-: Plenty of bass, but it was a little loose at times. Some of the better amps offer better bass control, and a little more definition. Still, this is only in comparison to the very best.
Neutrality: A-: It’s just a touch warm and rolled off on top from neutral. But it sure sounds pretty!
Soundstaging: B+: Soundstage depth was excellent. Image specificity was very good. Width was just good – soundstage width was not delivered in full measure by the Mini3.
Transparency: A-: Definitely an open, clear, generally clean, grain-free sound. Not the LAST word in resolution, but still very good.

The Mini3 can be bought for $125 completely built from Rockhopper audio. I understand MisterX may build them as well. For that price it represents an INCREDIBLE bargain. While I feel the Meier XXS offers better overall performance, even it costs $195. So the Mini3 is a VERY easy recommendation for someone wanting a very good, inexpensive amp.

Update 4/9/08

> Todd the Vinyl Junkie Portable Millet Hybrid

TTVJ Millett Hybrid Amp - $459.00 : TTVJ, Todd The Vinyl Junkie

I was able to listen to this amp under TTVJ’s loaner program. The PMH is of course the only portable amp with tubes in it that I am aware of. But it’s a hybrid – the tubes aren’t used to drive the headphones directly. Based on what I had read, I expected it to sound tubier than it did. But there are some sonic attributes that can probably be ascribed to the tubes. Less happily, the tubes are also likely the reason that the chassis rings very audibly through the headphones if tapped. This is really a bummer for a portable amp. It means that while it is portable, care will have to be taken while listening not to bump it, or unwanted ringing will overlay the music.

Build Quality: A: Very attractive and sturdy chassis. I guess I won’t subtract here for that annoying pinging…
Treble: A-: The treble is reasonably clean, transparent, and neutral. As I expected the amp lacks a little top end extension and air, but not nearly as much as I thought it might. I don’t think the treble is a real problem, generally, unless you try to use it with dark sounding headphones.
Midrange: A+: WOW. Simply gorgeous. Cliché or not, I have to assume this is due to the tube impact. But the mids were musical, lush, detailed, clean, open, and very enjoyable. The amp’s strong suite, no doubt.
Bass: A-: Full, punch, and fat. Perhaps a little loose. Could have a little better depth. But it was very enjoyable nonetheless.
Neutrality: A-: More neutral than I expected. Aside from lacking the very frequency extremes, it is essentially neutral . In fact, I was surprised to find it more neutral than the Decware Zenhead, which went through the review process at the same time.
Soundstaging: A: Great depth and width, and a very palpable image. Excellent performance here.
Transparency: A-: Occasionally just a bit thick sounding, but generally very transparent.

The TTVJ PMH provides very good, and in some respect truly excellent sound. It’s generally well built. But it’s at the very top end of the price curve of portable headphone amps, and for my $450, for portable use, I’d prefer the iQube, which performs better overall and doesn’t have that very annoying pinging/ringing. It might be better to leave the tubes at home.

> Decware ZenHead

DECWARE / High Fidelity Engineering Co.

NOTE: This review updated with new model July 09.

I was asked by Decware, a maker of many high-end tube amps, to review their portable headphone amp, The ZenHead. When I received it, I was surprised about the size – it’s BIG. It’s as big as the Lisa III. It uses a 9V battery, and has no charging facility. Like the Lisa III, it’s really too big for many portable applications. Decware’s Steve Deckert said that he did not really try to keep the size down for the same reason that he didn’t include a batter charging circuit – he was going purely for the best sound he could. Certainly a good goal. However, while in the case of the Lisa III I felt the superior sonics could justify the size, the Zenhead is merely a very good, competitive sounding amp, that is really big.

OK, OK, but how did it sound???? Well, very good. Overall, I felt that Decware’s main business of selling tube amps shows in how the amp is voiced. It sounds like many tube amps I have heard. As such, its sound is a little idiosyncratic. I struggled some with the normal ratings I give, in terms of capturing the essence of the amp. On some tracks it sounded fantastic; on others, merely very good. In it's "LoZ setting" it was more neutral sounding than the "HiZ" setting, so I used this mode.

Build Quality: A: Pretty industrial, plain looking case, but very sturdy, and solidly built. No turn on/off thump. Totally silent also – no noise at ALL. No points for style, but none deducted for cheap plastics – it’s all metal.
Treble: A: Treble is quite clear. Very transparent. Maybe not as extended as the iQube, but still excellent. Better than in version 1.
Midrange: A: Slightly lush, but very transparent, and clear. Highly engaging performance here. Again, better than in version 1 - liquid and smooth but with great nuance.
Bass: A: The bass was excellent. Full, powerful, punchy. Lacked the very last bit of depth that the iQube has, but still truly excellent.
Neutrality: A: The new version is basically neutral in "LoZ" mode - maybe just a very slight warmth in the lower mids and upper bass, but not enough to be problematic.
Soundstaging: A+: The ZenHead has selectable crossfeed. I found that its soundstage was deep and wide, and truly palpable. It excelled here, even better than the 2Move with the Meier crossfeed on. If you are a soundstage freak, this amp is for you.
Transparency: A: Definitely in the class of amps that presents a wide-open window on the music. Very good performance here.

The V2 of the ZenHead offers a quite "tube-like" sound in "Hi-Z" mode, and a more neutral, very transparent sound in "Lo-Z" mode. This makes a very good amp even better. I like the ZenHead a lot - I just wish it were smaller.

> Graham Slee Voyager

Voyager Portable Headphone Amplifier - A New Headphone Amplifier by Graham Slee

A Head-fier was kind enough to loan me a Graham Slee Voyager to test, since a lot of people had asked me about it. The Voyager is highly regarded in many head-fi circles, and indeed, it deserves some of this praise. It has some very good qualities.
One thing that it doesn’t have is good looks. It looks cheap as hell compared to any other headphone amp over $200, and at $350, one has to hope that there are a heck of a lot of high quality parts inside, because the cheap plastic case is pretty lame.
It has a “Contour” switch, which increases bass and treble. I have no use for such things, but some people might. Having a USB power option is kind of handy (it does not contain a DAC though).

In terms of sound, it was a very good overall performer with no real glaring weaknesses, but no earth-shattering areas of performance either.

Build Quality: B-: See above. Also, it pops loudly when powered up. The slider power switch is pretty cheesy too. Really uninspiring build quality, especially for the price. About the best thing I can say about it is that it probably would survive being dropped without incident.
Treble: A-: Generally clean and clear. Good detail, but perhaps just a bit too much sheen.
Midrange: A-: Again, generally clean and transparent, with no obvious coloration. Still, in direct comparison to the iQube, the mids of the Voyager are not as transparent. In fact, the mods of the 2Move are more transparent and open sounding than the Voyager’s. Still, it offers generally very good performance here, and female vocals were very pleasantly reproduced.
Bass: A: The bass was excellent. Like the Decware Zenhead, if has full, powerful, and punchy bass. It too lacked the very last bit of depth that the iQube has, but still very good excellent.
Neutrality: A: Generally very neutral. Impressively so, in fact. Only the slight treble emphasis subtracts here, and it’s not a big deal.
Soundstaging: A: Convincing image stability, and reasonable width combined with excellent depth give it a good score here.
Transparency: A-: Perhaps this is where there is a little failing – there seems to be kind of a gauze through which one hears the music – slight, but there. It prevented me from becoming fully engaged with the music in many instances.

So, I think the Voyager is a very good amp that is overpriced for what it delivers and how it’s packaged. It would be terrific in a nice metal case for $250. At $350 in a cheap plastic case, it’s simply impossible to recommend.

NOTE: All new amp reviews are now in later posts, with links below - only the rankings contain all reviewed amps (due to a limit on the size of the post)





Conclusions (12-20-10)

OK, so now it’s now 56 amps! NOTE: I have decided to change the way the rankings work. I have created LEVELS, rather than individual ranks. As before, note that the sum of the "Grades" I give does not always tell the whole story in how I rank them, since the whole is sometimes greater or lesser than the sum of the parts, and I am often forced to split hairs here, since the list has gotten so long. I have made no attempt to rank the amps WITHIN each level.  Within each given level, they are listed basically at random.  Also please note that even if these amps include a DAC, that DAC performance was NOT a factor in these rankings AT ALL. Also, for clarification, this ranking is based on sound quality ONLY, and does not take things like size or battery life into account.

Level 1:


Triad Audio Lisa III @ $600.00; Power supply is $350 additional/ Trian Audio L3 (newer version) Review here

MST Fi.Quest, @ $450 (Review here)

Meier Audio Stepdance @ $350 (Review here)

Ray Samuels Audio SR-71B @ $600 (Review here)

Ray Samuels Audio The Protector (in BALANCED mode only), @ $475 (Review here)

Level 2:


Qables iQube @ $605.00
RSA Mustang P-51 (review here) @ $375.00
Larocco Audio Pocket Reference II mk 2 (long ago discontinued)

Level 3:


ALO Audio RX Mk II @ $449 (review here)

Headamp Pico @ $349.00
Meier Audio 2MOVE (and the older MOVE) (3MOVE @ $270.00)
iBasso Audio D4 Mamba @ $219 (Review Here )
RSA SR71 @ $395.00 (original SR71, not the SR71A)
RSA The Predator @ $475.00
RSA The Hornet “M” @ $370.00

iBasso Toucan @ $229 (Review here )

Level 4:


Decware Zenhead @ $295.00
Xenos 1HA-EPC (discontinued)
RSA Tomahawk @ $295.00
Meier Audio XXS / Headsix @ $166.00/187.00


Level 5:

TTVJ Portable Millet Hybrid @ $459.00
iBasso D3 Python $219.00 (review here)
Xin Reference @ $279.99
Meier Audio Porta Corda III (discontinued)
Xin SuperMicro IV (current version auditioned 1/22/08) @ $199.99


Level 6:

ALO Double Mini3 (review here) @ $235.00
Headamp AE-2 @ $349.00
Graham Slee Voyager @ $233.00 + S&H from UK
Linearrosa W3 @ $299 (review here )
Leckerton Audio UHA-6S @ $309 (review Here )
iBasso D2 Boa $165.00 (review here)
Go-Vibe 7
Mini3 (Price depends on build) built @ $125.00


Level 7:

Leckerton Audio UHA-3 @ $189.00
iBasso T3 @ $119.00 (Review here)
Portaphile V2^2 @ $275.00
Linearrosa W1 (review here )
mSeed Spirit (discontinued)
Mini-Box E @ $229.00
Storm 3 (NOT B3) (review here)
Storm Little-2 (review here)


Level 7:

Storm B4
Visely HEA-4 @ $149.00 (Review here)
iBasso P-1 (discontinued)
Visely HEA- 1 @ $135.00

Microshar uAmp107 @ $135.00
Practical Devices XM4 @ $135.00
C&C XO @ $209.00


Level 8:


Music Max LT1 $99 (Review here)
iBasso T2 (T4@ $109.00)
NuForce $99 (review here)
Go-Vibe 6 (discontinued)
Xtra X-1 Pro @ $104.00
Xenos 0HA-REP (discontinued)

iBasso T1 (discontinued)
Xtra X-1 (discontinued)
C&C Box V2
Storm B3
Little Dot Micro+ (discontinued)

I apologize in advance if you liked the old ranking system better, but as this review has gone on over time, and as it has grown, I think this is a better approach.  As always, this is JUST MY OPINION, but I hope it has been helpful.

Edited by Skylab - 12/20/10 at 11:29am
post #2 of 3234
Really nice review skylab.

Its good to see the popular portables compared and I have been waiting for you to do this.
post #3 of 3234
Great review Skylabs, I think I'll definitely take a look at the Headphonia and the XM4.

-The Grinman
post #4 of 3234
Truly an enjoyable read, Skylab!

Thanks for taking the time to do such an impressive overview. I think we'd all love to be able to have a play with so many amps!

Cheers, Dex
post #5 of 3234
Something glitched my reply...

Just wanted to add thanks for taking the time to do such an impressive overview. I'm sure we'd all love to have a play with so many amps!
post #6 of 3234
Great review Skylab.

Especially as I'm on the lookout for a new portable amp and you've covered the ones that I would be considering (as well as some others that I wouldn't but maybe should be!)
post #7 of 3234
Interesting review and I know you must have spent many hours going back and forth. It would be interesting to read your impressions of the Xin IV or the LE, which can also drive many types of phones.
post #8 of 3234
Thread Starter 


For the review I used the following headphones:

•Early reviews: Sennheiser HD25-1 (primarily), 2005 Beyerdynamic DT770/32 ohm, 2005 Beyerdynamic DT880/250 ohm
•Middle reviews: Denon D5000, AT-ESW9, Ultrasone HFI-780, Sennheiser PXC350, AT ESW9, Kenwood KH1000
•Later reviews: Sennheiser PXC350, Shure SRH840, Denon D7000, DT770/32 Ohm

•Current reviews: Sennheiser PXC350, Beyerdynamic t50p, Ultimate Ears Triple-fi 10

Early on I listened to some with Shure E500’s, but that was not part of the “formal” test.

Music used for the review:

•Patricia Barber – “All or Nothing at All”, Nightclub
•Holly Cole, “Looking for the Heart of Saturday Night”, Temptation
•Crash Test Dummies, “In the Days of the Caveman”, God Shuffled His Feet
•Dave Matthews, “Oh”, Some Devil
•Jenny Lewis with the Watson Twins, “Handle With Care”, Rabbit Fur Coat.

Listening was done with the levels matched to within 1db using a RS SPL meter, so that the listening volume level was identical with each amp. Source was a RedWineAudio iMod iPod, connected with an RnB Audio interconnect.

No attempt is going to be made here to completely describe each amp – this has been done plenty of places on this site. Rather, I scored the amps based my listening in the areas of midrange, treble, and bass performance, transparency, neutrality, soundstaging, build quality, and other pertinent comments. I used an academic grading scale, but as in most academics, the lowest grade any of these amps got was a B-, since they were all pretty good.

Please note that this is still just a subjective review, in spite of my attempts to standardize the testing. While reference amps were always used in the comparisons, due to the large number of amps involved, and the time horizon of this review, direct comparisons between every amp is clearly neither practical not possible. Also, in case there is any question, I either purchased all of these amps with my own hard-earned money, or they were temporarily loaned to me - any amp I have kept I purchased. Also, they are the stock amplifiers – no mods of any kind were done. Where there was a bass boost function, it wasn’t used.

Edited by Skylab - 11/4/10 at 9:31am
post #9 of 3234
Really great review Skylab.

compact and very useful. Now I'm considering to try the headphonia.
post #10 of 3234

Xenos 0HA ?!?

Skylab, what's the point in including the Xenos 0HA in your review, when it's long been out of production? There have been several steps of evolution in the meantime, 0HA-R, 0HA-RHP, 0HA-REP (hoping I'm not missing some).

Some people could easily be (or want to be ) misled by this.
post #11 of 3234
Great review. Makes me more happy that I bought my Hornet .
post #12 of 3234
Originally Posted by Skylab View Post
So, in the end, here’s how I ranked the amps:

1.Larocco Audio Pocket Reference II
2.RSA The Hornet
3.RSA Tomahawk
5.Practical Devices XM4
6.Xenos 0HA
7.Go-Vibe V5
8.Little Dot Micro+
Especially as you wanted to include it in your ranking, without even a slightest mention of the fact that it's a surpassed product that's not made anymore.

The misleading that this can generate at a superficial or uninformed sight is obvious, given that "0HA" is common to the entire series of amps.

Would/could you have done the same with, say, a Xin Supermacro v1 ? No, I think not.

It's an instance of what I would call "forum narrowness".
post #13 of 3234
Thanks for the review, Skylab! Have you ever listened to the Headroom Micro amp? If so, any thoughts on how it compared with the amps you reviewed?
post #14 of 3234
"I had as Xin Supermacro IV for a few weeks, and while I thought it was a good amp, I preferred both the Hornet and the PRII, so I sold the Xin (long before I did this review). But the Xin was in that category of amps that make you go "wow", to be sure. I just don't like Xin's business practices."

Well I have to admit the wait can be long for the Xin amps and not always will people be happy with not hearing replies to all their emails. One problem with comparing the Xin amp is that you can use so many different opamps, which greatly impact the sound quality so to pin it down to one sound is impossible. I had the SR71 for some time and enjoyed the sound and quality but in the long run with the right opamps I got a larger stage and greater dynamics with the SM3 running on 2 634 buffers per channel and the 5534 bypassed opamp.
post #15 of 3234
Great review...I'm also waiting, not so patiently at this point, on the Diablo and will be interested to see how it compares to the Tomahawk which I love. Hopefully we'll see the amp shortly...
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Head-Fi.org › Forums › Equipment Forums › Portable Headphone Amps › Review: Portable amp roundup! 56 portable amps reviewed and compared - FINAL update 12-20-10 added RSA SR-71B