Fostex HP-V1: Tantalising

The Performance

Like GoVibe’s awesome Portatube, the HP-V1 scores about as good as a hybrid valve headphone amp can. Every hardware test I subjected it to failed to bring it to its knees. It upholds extreme resolution to just about every earphone/headphone on the market; which, I should remind you, isn’t true across the board. No matter how awesome it sounds with Beyerdynamic’s DT880 or T1, the ALO Audio Continental, for instance, isn’t capable of keeping a stable signal when driving low-Ω earphones.

But before I get into the nitty gritty, I’d like to cover background noise and channel balance. I wish I could say that both were perfect. Because the volume pot is extremely sensitive to movement earphone users will run into high output levels even at early low gain volume settings. While driven well, sensitive earphones get too loud, too quick. Sensitive headphones have about double the headroom before they get too loud. Why this is unfortunate is that HP-V1’s power plant is super capable. It can drive anything with absolute stability. But as reality pans out, portable headphones and earphones have very little headroom between great balance and volume levels too loud – or safe – for listening. The Portatube, by contrast, suffers no such problems.

As a consequence, I don’t recommend using the HP-V1 with your favourite earphones or sensitive portable headphones. You very likely will hurt your hearing.

Background noise sits almost on a level with a 2005 iPod nano. Unlike the iPod, however, that noise is clean, untextured, and draws very little noise to itself. It is barely audible through sensitive portable headphones, and whilst music rolls through its circuits, is almost inaudible through any output device.

Naturally, the HP-V1’s sweet spot is high-Ω headphones. In fact, with my favourite DT880/600, control over the usable volume range extends to over 90%, with no marks lost for upticks in distortion. Both balance and pot travel are perfect. Personally, I listen to modern recordings at levels of up to 65% in L gain mode and older recordings at up to 85% before feeling uncomfortable. Neither noise nor undue distortion are exacerbated by raising the volume. But for best performance, keep the volume pot set below 90%.

HP-V1 delivers impressive dynamic range and noise performance that rivals, or beats the Portatube, and which is almost able to match the excellent Portaphile Micro OPA627. The differences are so slight, however; no one will be able to suss them.

Where differences make their entrance is in IMD and THD, both of which are literally orders of magnitudes higher than the Portaphile. But, that’s part of what makes valves fun. I’ve yet to test a valve amp that isn’t massively tipped toward harmonic distortion. And truth be told, distortion done well sounds great. It can be an excellent masking system for headphones that  trend to tizzy and wild  upper mid heights, or which favour sibilant percussion. Essentially, the HP-V1 adds a softening filter or glow to edges that otherwise, would be harsh.

The good news is that none of that softening affects frequency balance. Balance is perfect at all times. Stereo effects are extremely wide, and can, at times, be overwhelming. In fact, channel separation is so extreme for a valve amp that it rivals high-performance solid state amps. The Portatube doesn’t even come close. Even under load, stereo width can get so wide that the ears, which are used to hearing both left and right channels simultaneously, can get confused. With amps getting higher and higher in performance, the need for crossfeed circuits becomes more apparent. Besides fitting with ample room on the HP-V1, a crossfeed circuit would suit the massive performance the HP-V1 amp serves up.

Update: I should mention that I was able to get a minimum of 9 hours playback time while burning this poor amp in all day IEM comparisons.

The Sound

Being a fan of the DT880, my options in the valve amp world are many, and great. It is a headphone built for valves. It has some tizz in the upper midrange, and a slight penchant for sibilance in the lower treble. A good valve amp like the HP-V1 smooths that mess out. I’m also an intense fan of the Audeze LCD-X, but one that cannot afford it. The distance between the DT880 and the LCD-X shrinks measurably with the introduction of the HP-V1, which smooths out the DT880’s notches.

Like the Portatube, the HP-V1 projects energy and verve with one hand, and with the other, intimacy. It’s not an intimacy you get from solid state amps. From top to bottom, the output signal is linear, but the feeling you get from the HP-V1 is very different. Unlike solid state amps, the transitions between upper mids and highs is ethereal, almost billowy: audibly delineated, but trending toward liquefaction rather than a ratcheting and de-ratcheting of one frequency into and out of another with absolute precision.

Absolute detail freaks will probably prefer something like the Cypher Labs Theorem 720, or the Portaphile Micro. But even paired with so-called ‘veiled’ or ‘slow’ headphones, the HP-V1 punches enough speed buttons to keep pace with any music. Personally, I prefer mating it to headphones like the DT880 and benefiting from one of the most lush midrange presentations out there. If your headphones have a trippy part, HP-V1 will lovingly melt it away.

Like the Portatube, it’s the maturity of its approach to music that I really like about the HP-V1. Music isn’t something to merely reproduce; it’s something to exult. And exult this amp does. Even tizzy 1980’s New Order and Duran Duran stuff mellows out. Raw ends grow up. And through the HP-V1 my sometimes-shrieky DT880 really latches onto a bit of that excellent Audeze ethos. It is smoother, more intimate, closer. Tizz has left the building. The same goes with the detail-oriented Sleek Audio CT7.

The Meh

With the exception of the jumpy volume pot, and, in light of excellent HiFi ergonomics, the sole 3,5mm headphone output, there are few detractors to the HP-V1. It is a solid design with solid performance. Provided the right headphone pairing, or a keen liking for softer, more intimate sound, it is an amp that will take your headphones for a ride.

It has plenty of power to boot, too. But lacking perfect control over the volume pot, that power is a detriment

The Conclusion

I’ve since cut my hair. I look weeks younger. But the HP-V1 is gone. It’s not like I’ll try endlessly to replace it. I get over things. But I can’t help looking back. The HP-V1 does most of what the Portatube can, but does it in a well-built, well-designed package, both things the Portatube eschew for a garden-variety slop. The main hitch is the volume pot. Where’s the 6,3mm jack? And why the hell does the pot rotate so damn easily and why is it so sensitive? I’m tempted to say, so what? Everything else that makes an amp great the HP-V1 sports in spades. It is one of the finest portable creations, ever. And whether in mourning its passing from my life I drink myself to death or not, that won’t change. I will miss you.

Thank you Fostex; bliss, even when short-lived, is after all, bliss.

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Back before he became the main photographer for bunches of audio magazines and stuff, Nathan was fiddling with pretty cool audio gear all day long at TouchMyApps. He loves Depeche Mode, trance, colonial hip-hop, and raisins. Sometimes, he gets to listening. Sometimes, he gets to shooting. Usually he's got a smile on his face. Always, he's got a whisky in his prehensile grip.

45 Comments

  • Reply April 17, 2014

    Dave Ulrich

    Awesome!

  • Reply April 17, 2014

    L.

    I SO want to hear this now!

  • Reply April 17, 2014

    K.

    Epic! I am not too sure about Japan becoming a prefab plastic land….I still have found memories, and always feel lucky to travel back….I had prejudices about this amp, but I have failed to spend time with it. Experience, experience….

    • Reply April 17, 2014

      ohm image

      Japan is all about prefab plastic. It’s all around. There are no houses even today that have anything but pre-fab outsides. Inside, it’s all plastic veneers. And since that is now normal… real materials are becoming expensive. And the average Japanese doesn’t even know the difference because they are so used to fake.

      That aside, this amp is the real deal. The only one I may slightly prefer to it is the amazing Portaphile, but it is trumped in several key areas by the HP-V1.

      • Reply April 30, 2014

        K.

        Thank you Nathan. I am not sure where I can try the Portaphile…I have lived in Japan for a few years, but that was – I realise now – a long time ago. Nostalgia still makes me buy “made in Japan” products…

        • Reply May 1, 2014

          ohm image

          I thin the V1 is a great example of what ‘Made in Japan’ products can be. it is beautiful, well-engineered, and sounds great. With the placement of rear and forward inputs, it is a breeze to use, too. I think Fostex outdid themselves with this design, and, for the most part, outdid much of the market. It is worth the label back from when the label meant anything.

  • Reply April 17, 2014

    spudgered

    Nathan, nice review, what’s the battery life/runtime like? Thanks.

    • Reply April 17, 2014

      ohm image

      I’ll have to update that, sorry. It’s about 9-10 or so hours. I had no problem listening for a day.

  • Reply April 17, 2014

    ohm image

    As stated under the performance section, I got around 9 hours per charge, sometimes more. Often I didn’t charge all the way.

  • Reply June 11, 2014

    Arne

    How is this compared to the Cypher Duet when it comes to sound stage/bass response and overall quality? I can unfortunately not listen to either one and have to go on reviews.

    • Reply June 11, 2014

      L.

      I’m afraid I don’t have the Fostex. Let’s hope Nathan sees this question

    • Reply June 22, 2014

      Marc

      I too am quite curious of the differences in performance between the Duet and the HP-V1 other than just tube/solid state. On a side note, has anyone here heard the HP-V1 with the Fidelio L2?

      • Reply July 17, 2014

        ohm image

        Marc, I borrowed both units, so I can’t give a good rundown between them. DUET has better benchmark performance, but if you are looking for a _sound_, V1 gives a sparkly version to the classic valve skew. I love it. DUET is also a balanced amp, which the V1 most assuredly isn’t.

        • Reply October 26, 2014

          Marc

          Nathan, would you have heard the Analog Squared Paper TUR-06 by any chance? If so, even if based on memory, may I ask for a comparison with the HP-V1? I’m very keen on buying a transportable tube/hybrid amplifier for my Fidelio L2.

    • Reply July 7, 2014

      ohm image

      Sorry, I didn’t get a notification of this question. The question you asked is very subjective. I’m of the strong opinion that slightly more intimate stereo images help the ear to better understand width.

      The V1 and DUET both output incredible stages with lots of details especially in the midrange, where most spatial cues are formed. V1 also gives more of a contrasty sound so you may find that it is more 3D, but again, that depends on how you listen or what you listen for.

      I prefer the V1 on most fronts, but DUET is a far better IEM amp (perfect gain stage, doesn’t get hot) and I’m more an IEM guy than a headphone guy. It depends on what you need.

      • Reply July 8, 2014

        Arne

        Very informative – thanks a lot.

  • Reply June 14, 2014

    Vaibhav Pisal

    this review has made me want to get dt880 and a tube amp.

    recently auditioned akg q701 with alo pan am for very good pairing.

    i thing neutral headphones like these with tubes are way to go for me (for now)

    • Reply July 7, 2014

      ohm image

      That is an awesome configuration. I really with Fostex installed a 6,3mm jack though.

  • Reply July 28, 2014

    lowbies

    Hello..please help me deciding which amp I will use for my ocharaku kuro..my setup : iphone 4s + fostex hp-p1. My goals are making my kuro to have little more bass impact (not overpowered one) and adding more resolution + 3D sense of space. My option right now are fostex hp-v1, alo continental, pico slim, portaphile 624/micro or maybe vorzuge ii? I didnt like super dark amp like national because it’s smoothened the kuro’s treble too much..yes I’m a treblehead btw 😛

    • Reply July 31, 2014

      ohm image

      The HP-V1 won’t give any headphone more bass. It will fix bass deficiency from sources that are unable to supply the right current to sustain the right amount of bass from low-Ω earphones.

      For a clear tubey sound, the HP-V1 is the best. For a husky tube sound, the Continental is best.

  • Reply August 13, 2014

    Nat PML

    Hi Nathan, I’m in love with the HP-V1, which I bought on a whim after reading your review (not really an habit) !

    Yes, it’s a shame there’s no 6.3 mm jack, and the volume pot rotates to easily, but that sound is magic ! I can’t listen to my other portable amps, now. I miss the way the Fostex sublimates everything. With DT770/32, it’s just perfect. Things come to life. Thanks to your review, I discovered what I believe to be “my sound”.

    Now, I need to find a desktop version of this. Can’t live without it now !

    (I’m also very curious about the Continental, and asked ALO when it would be back, and they answered a v4 was on its way.)

    • Reply October 3, 2014

      ohm image

      You keep using past tense words. Did you sell the Fostex? I’m with you: it is magic. Glad this review helped.

  • Reply October 10, 2014

    Aldy Ariffi

    Hi Nathan, I am seriously considering to acquire this amp after reading your review. Well, for several times 🙂 Even the packaging looks good (someone post the photos of unboxing his hp-v1). Do you think this amp pairs well or would have good synergy with hd650?

    • Reply October 26, 2014

      ohm image

      I’ve not used the HD650 with it. As long as you’ve tried, and liked HD650 with rich amps, then the HP-V1 likely will love your phones. I’m a HD600 man, so I’m a bit… off of your target. That and the HP-V1 wasn’t mine.

      That said, I’m going to purchase one in January. The prices are good here in Japan.

  • Reply October 17, 2014

    s. zorin

    Do you know if this amp can drive Beyerdynamic T1 ? T1 are 600 Ohm headphones like DT880 but T1’s impedance peak at bass frequencies, centered on 100Hz, is about 1300 Ohm and DT880’s impedance peak is only about 730 Ohm – a big difference as it is harder to drive headphones drivers that have high impedance numbers. Must be tried against the Continental to see if T1’s bass is as good with HP-V1 as it is with the Continental.

    • Reply October 17, 2014

      dalethorn

      It’s not in the specs, it’s not in the owner manual, and it’s not discussed in 50 or more reviews I read. I bet no, unless you compromise the bass a little bit in some music. What would worry me more in portable use is the heat.

    • Reply October 26, 2014

      ohm image

      My DT880 are the 600Ω kind. They run like a dream on the HP-V1. The only thing to maybe worry about is that if you are very loud volume listener, you may not get crazy volume levels. That said, I couldn’t listen with the volume pot turned too far on the HP-V1 with the DT880/600. It supplies great current to high voltage settings, and therefore, thick, rich sound even when you are blasting things.

  • Reply October 18, 2014

    Patrick Michael Graf Murray

    I know this is probably not ideal for 600ohm headphones, but I wanted to ask on how it could drive something like the HE-560 and other orhos like that and the T50RP modded ones like ZMF x Vibro? Please get back to me on this

    • Reply October 26, 2014

      ohm image

      I don’t own the 560, but do have the ZMF headphones on hand (for another couple of weeks, until the review is out). They are no problem at all. The HP-V1 puts out good current into all voltage levels, and can sustain a good signal. That said, it doesn’t get super duper loud, but even at its loudest volume settings, it pushes excellent quality signal that doesn’t piddle out or get thin.

  • Reply October 28, 2014

    Marc

    Nathan, would you have heard the Analog Squared Paper TUR-06 by any chance? If so, even if based on memory, may I ask for a comparison with the HP-V1? I’m very keen on buying a transportable tube/hybrid amplifier for my Fidelio L2. (I’m unsure the comment saved the first time I posted it. I don’t see it on mine).

    • Reply November 27, 2014

      ohm image

      Marc, I do not own that amp, but I may be able to get ahold of one long enough to write a review. That said, the V1 isn’t mine and was sent back long ago. If I purchase one it will be when it has a 6,3mm headphone jack. If and when that happens, I will be sure to kick up a comparo.

  • Reply January 25, 2015

    Haryanto Suryonoto

    Nathan, what do you think Fostex HP-V1 against GoVibe Portatube+?
    I’m a daily swinger between Audeze LCD-3, B&W P3/P5 and Beyerdynamics T51P. Looks like Fostex is more superior to the Portatube from your review above.

    • Reply September 18, 2015

      ohm image

      I’m sorry this is late. Portatube+ has a DAC. This one doesn’t. If you need a DAC, there’s only one choice. Apart from that, I reckon this is the better amp.

  • Reply February 2, 2015

    Ian

    Is the HP-V1 able to drive the TH900?

    • Reply February 2, 2015

      dalethorn

      Do you really need portable use?

      • Reply February 2, 2015

        Ian

        I’m considering purchasing the TH900s and would like it if I could use them in different parts of my house without having to be tethered to my PC. I don’t plan to take them to work or into town though.

        • Reply February 2, 2015

          dalethorn

          That’s good, since using indoors will require less volume. More power would be better to get the most out of the 900, and one possibility is to get an amp that has a DC input from a “wall wart”. With those amps you can usually rig up a battery pack to supply the DC current, and while it’s heavier, it’s still easy to carry if you configure it right.

    • Reply September 18, 2015

      ohm image

      No problem.

  • Reply September 13, 2015

    Yaroslav

    Hi Nathan, do you think they are a match for HD650? Not in “portable” sense, but for trans-portability, of course?

    • Reply September 18, 2015

      ohm image

      I’m not a big fan of the HD650 and therefore don’t own it. So, I’m not qualified to suggest that the V1 does justice to them. I hope you get some good feedback.

  • Reply August 19, 2016

    Warren peace

    Nathan-

    I know you wrote this years ago, but I actually have an HP-V1 with 6.3mm headphone jack. It might be available if you happen to still want one. I wouldn’t be against some kind of trade where I end up with a 3.5mm one, either. The advantages of my unit are wasted on me. When I saw it for sale though, I thought “now that’s rare,” and I had to snap it up.

    I agree with the above commenter who mentions using it to carry around the house and set down in whatever room you’re in. It’s absolutely perfect for that sort of use, or at most taking to a friend’s house. If you want something pocket-portable to enhance your phone/DAP, there are plenty of better, cheaper options. This one’s “home-portable,” and still extremely useful in that capacity.

    I have to agree as well about the synergy with the DT880 (mine are 250 ohm). Thanks to Fostex I can’t stand to plug the 880s into any SS amp anymore, at least none I’ve heard so far. The same synergy goes double with My Grado sr225e. In fact that’s probably my favorite combo of all combos right now.

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