Review: Phatlab Audio Sassy – sassy?


Sassy and Phantasy share a clutch of design and utility principles. They share very little, however, in sound. Sassy wakes up almost instantly, ringing like Phantasy, for a dozen seconds to a minute, but from the ON, spits a strong signal that needn’t a warm up. Phantasy clinks and clunks like an old car for a bit; Sassy purrs from the get-go, lickety split.

Phantasy cools signals, clarifies, rings; it plays music like you may not have heard before, or may not have heard in a long time. Sassy warms up music as you expect a hybrid design to do; and it does so at almost no expense when under load.

Phatlabs Sassy - face

Which means that, unlike Phantasy, it doesn’t really have a sweet-spot headphone or earphone. I note mostly stable loaded signals at volumes of up to 50%, with minor frequency aberrations from 20Hz – 20.000Hz. And I note a ~50% rise in harmonic distortion going from unloaded to high-current loads like the Earsonics SM2 and Audio Technica ES7. 50% is practically nothing. Astell & Kern’s AK380 THD base rises by ~22.000x. Of course, it starts much lower than Sassy’s, but still. Sassy’s unloaded base THD numbers are high, reaching 10x that of ALO Audio’s CDM – loaded!

I measure unloaded base THD levels at 3,08% at 50% volume, rising to 3,3% when driving the 600Ω DT880, 4,93% when driving the Earsonics SM2, and 5,18% when driving the Audio Technica ES7. IMD is both similarly high, and similarly load agnostic. Base levels of aberration are high, but they don’t ratchet up quite like they do through most amplifiers. And, assuming you keep the volume pot below 50%, they commit few to no audible boners.

Hardcore valve fans will probably call Sassy’s warmth mature. Sassy doesn’t bloom. It doesn’t peal when hitting high frequencies. It’s tubey, but tempered. Anything but sassy.

Sassy isn’t as warm or goofy as, say, the Woo Audio WA3. It doesn’t bloom in any frequency. Forward-edge ring is pretty high, but this is valves we’re talking about. Stereo signals congeal somewhat in the bass and lower mids. Consequently, highs are clearer than they have any right to be considering Sassy’s proclivity for warm harmonic distortion. In that respect, they resemble, though not slavishly, the clarity and character of Jaben’s wonderful GoVibe Porta Tube.

Phatlabs Sassy - ISO ass

Warm lows are centrally grounded, and extrude the least stereo detail in the entire frequency range. But their warmth, smoothness, and deep anchor pull everything together.

Sassy’s volume pot controls a wide volume range in a pretty short turn. I listen most often to volumes of around 25% (DT880), 15% (Ultrasone IQ, Grado PS1000, Audio Technica ES7), 20% ZMF headphones. Like Phantasy, low volumes experience noticeable balance lean, in my case, to the left channel. For that reason, sensitive headphones and ears may find it hard to achieve absolute channel balance at comfortable listening levels. A good bed-time rig Sassy and the Shure SE846 or Ultrasone IQ do not make. I’m good with older recordings at that volume through the PS1000 and IQ, but only just.

So maybe the DT880/600 is Sassy’s sweet spot? Sensitivity wise, perhaps. It is my opinion that the PS1000, whose strangely sucked out (or up?) high midrange, needs a good grounding. Sassy provides the warmth necessary whilst avoiding splash, bloom, and other rowdiness you sometimes find in high-distortion valve amps.

And I should explain a bit more about that warmth. It’s not a top-down veil. Dear God, no. Tones are clear, just not bell-like. It’s a chamfered edge, smoothing out the join between noise and stereo detail. It’s a natural warmth, something you recognise at a quiet jazz lounge. But it’s warmth. For that reason, I reckon Sassy is less well adapted to the fast, the violent; it suits complicated, but moderately paced compositions from classical to jazz and vocal, and folk instrumental and rock. But stereo-detail started trance and EDM heads may be better suited by a number of other amplifiers.

If you’re willing to sacrifice clarity and accept IDM and THD levels of up to 5%, Sassy can put out 100dB of signal to noise, and 99dB of dynamic range. Impressive for a valve amp of any flavour. Sassy gets loud, and it stays pretty stable. It’s warm, but not too warm. In its own way, it is both less and more tubey than Phantasy. Less: Phantasy is brighter and subjectively clearer. More: Sassy is warmer. But because it holds a stabler signal to all loads, it is more suitable to a wide variety of headphones.

End words

Which is the safer Phatlab amp? Gosh, Sassy gets the job done with minimal fuss. It is warm, and stable, but for me, less engaging. I love bright. And while Sassy doesn’t fall off with low pass filters or anything, its aberrations stack up for a truly nice listening experience. Nice when you’re looking for a bit of warmth is one thing. Nice when you’re looking for accent is another. It’s a good experience. Sassy is made as well as any battery powered amp out there – that is, as long as you strike Phantasy off the list. It’s got nice lights and Cylon detailing. It’s the tubey sound you probably expect from a hybrid tube amp. Getting used to it is like pouring milk on your Wheaties.

Well done. But definitely not sassy.


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.


  • Reply April 7, 2016


    Another really nice review!
    Could I ask again what I asked with regards the Phantasy – do you know from the company (or could you find out from them, as my attempts at contacting them have failed) where I could buy either or both of these in Europe? I live in the UK but perhaps there is some alternative place I could order from, preferably without import duties as the Phantasy will be stretching my budget as is! And I kinda fancy both to be honest!
    I was about to purchase two relatively expensive desktop amps but one could go and be replaced by definitely one of these, perhaps both.
    I know you ultimately prefer the Phantasy, but do you consider its limitation in matching many headphones to the fullest to be a drawback that makes the Sassy almost a better option (money not being an issue)?
    Hope you are able to find this info for me, as well as for others who may be interested.
    This is not flattery (I abhor flattery!), but i really like your writing style in these reviews; hope there’s more to come.
    Be well.

    • Reply April 11, 2016

      ohm image


      I’m sorry this reply is late. I burn out over the weekends and move as far from audio stuff as I can. I will ask Mr. Lin to check his email or to give me information re: European distribution or direct sales that I can then append to this post.

      Phantasy’s drawback is exactly what you said I said: you need to match it to the right headphones. But when/if you do… Phantastic. Sassy is, as I hope I outlined, far stabler across a wide variety of headphones – and therefore the more logical choice for a person intending to use it with earphones, headphones, and low-Ω headphones.

      That said, the sound between the two is quite different. Sassy is much closer to – though ‘warmer’ by way of higher distortion levels – than the ALO CDM and even closer again to Cypher Labs’s Trio. Phantasy is completely different. I’ve not heard its like among portable tube amps, and even among SET amps, it is perhaps the clearest, bell-like amp I’ve used.

      So… while I can’t decide for you, I can say this: if I had to choose just one for my favourite headphones (excepting the PS1000, which tend to be high-Ω), it would be Phantasy.

      As to the compliments: thank you. I am trying my best.

    • Reply April 11, 2016

      ohm image

      Mr. Lin said that you can buy from him direct until his European (or other) distributorship is finalised. I will update the article tomorrow or the day after with his instructions.

      • Reply April 11, 2016


        Many thanks, and no worries about the initial delay in your response; I know you guys are busy at the best of times, and more often than not in life, times are frequently not ‘the best’.
        Take care of oneself and ones loved ones, and the rest will wait till its time comes.
        Be well.

  • Reply April 11, 2016

    Barun C

    Nicely done Nathan, although Phantasy still piqued my interest as it seems to be a promising portable setup for people on the move who want a portable desktop amp. The portable amp market has shrunk but I still see quite a few people using portable amps like the FiiO E12A and recently Mojo (although it is more than an amp) with lower tier to mid tier DAPs and phones. Do you still see people carry their AK DAPs with portable amps in Japan?

    • Reply April 11, 2016

      ohm image

      I rarely see naked DAPs. It is strange. People even strap amps to Mojo! so stacks today are as big as ever. That said, I’m sure they do this mostly at meets. Geek street cred. I can’t imagine it being popular or comfortable to strap on on the way to work or school.

      Personally, I go naked.

      • Reply April 11, 2016

        Barun C

        I also consider carrying naked or solo for a while now for convenience, currently with the QP1R and earlier with the iBasso DX-50, iPod Classic 160GB and Zen Vision M 30GB.

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