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Pass Labs HPA-1 Headphone Amp Review

Rate this headphone amplifier:

  • 1. Poor (headless panther)

    Votes: 320 90.4%
  • 2. Not terrible (postman panther)

    Votes: 19 5.4%
  • 3. Fine (happy panther)

    Votes: 6 1.7%
  • 4. Great (golfing panther)

    Votes: 9 2.5%

  • Total voters
    354

xnor

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Let me make another shocking statement: Better measurements don't correlate with better sound. :eek:
That's why on the one side measurements are demonized and biased impressions are redefined as a device's sound.
On the other side, audibly irrelevant improvements in measurements are elevated above everything else and are treated as if they were.

If all you need is an amplified signal then looking solely at measurements may be enough.
But if you need a dedicated amp then there is much more to it like the volume control, inputs and outputs, gain and gain switches, maybe even features like crossfeed circuitry, and even looks...

Case in point, look around this forum and you'll find people that bought amps based on highly praised measurements but are unhappy with them.
Sometimes it's even because of the sound due to unrealistic expectations fueled by measurement hype based on incorrect assumptions about audibility.


Given these measurements, is this amp's technical performance poor, especially for its price? Yes.
Does it matter? Depends.
 
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Vacceo

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Honestly I’ve yet to see Pass Labs product that, price notwithstanding, seemed to be worth a damn. Build quality problems, controls that don’t work, high susceptibility to ground loops - and for what?

Admittedly, all basic (no DSP) audio electronics are just so boring to me. Either they’re completely unremarkable, or they suck.
Pass makes Death and Black Metal sound disgusting. If any amp consistently makes a whole genre sound bad, the amp us worthless no matter the price.
 

Purité Audio

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Fine measurements correlate with transparency,
Keith
 

Alcophone

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Is it?

View attachment 245257


Seems they were selling high fidelity, not emphasizing it's pleasing distortion characteristics.
A matter or definition. To me the war started a few years ago when Schiit had to start catering to objectivists because too many people were suddenly influenced by the ASR hive mind, affecting Amazon reviews, Drop.com discussions, Reddit posts, etc. Before then it was clearly easier to find market appeal. I don't think quite as many people had some sense of what SINAD means before then, either. Amir has certainly been influential.
 

fpitas

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A matter or definition. To me the war started a few years ago when Schiit had to start catering to objectivists because too many people were suddenly influenced by the ASR hive mind, affecting Amazon reviews, Drop.com discussions, Reddit posts, etc. Before then it was clearly easier to find market appeal. I don't think quite as many people had some sense of what SINAD means before then, either. Amir has certainly been influential.
The tube amp market continues to degrade over time, though, as seen by the (expensive, highly regarded) lemons that Amir has tested. They don't have to be bad. It's almost to the point you have to build your own from a DIY source to get fidelity.
 
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Rick Sykora

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You don't listen.

You just check the measurements and buy based on that.

Simple.

IF you read the review, Amir did listen to this amp.

So you have the benefit of both the measurements and his subjective comments.

Simply the best of both worlds!
 

DonR

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IF you read the review, Amir did listen to this amp.

So you have the benefit of both the measurements and his subjective comments.

Simply the best of both worlds!
Although I value objective measurements much more over subjective sighted impressions, I would like @amirm to listen to the equipment first before doing his measurements so as not to bias his opinion and if he did do this, then state as much in the review.
 

Rick Sykora

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Although I value objective measurements much more over subjective sighted impressions, I would like @amirm to listen to the equipment first before doing his measurements so as not to bias his opinion and if he did do this, then state as much in the review.

This has already been litigated ad nauseum in other threads. If you have not read elsewhere on the forum, the short of it is Amir's preference and he has his reasons.

If you want to take it up with him, suggest you do your research first and PM him.
 

WayneC

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I thought I would post this to clarify things a bit. This was designed by Jam and not Nelson or myself. It also isn't the commercial version of the WHAMMY. Jam was given autonomy in the project since headphones were an interest of his. Our website and numerous reviews and interviews make pretty clear who designs what.

If you want something that measures below .0005% distortion and noise look at the BA20018 circuit I did. It is in the public domain and I think you can even get boards for it.
The Whammy is another dedicated headphone amp you can build. It is an op amp driving source followers and you can roll in your favorite one and set the bias how you like.
FYI I don't make a penny on these.

Given the measurements on the HPA1 and the loose connector I would like to see it at the factory. Call and ask for Kent and he can arrange to get it back.
 

pma

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Look - it might have been and should have been designed much much better, regardless there is Jam behind it. Flaws are unexplainable. We can see that most of the “legendary” designs and approaches were a bubble, just names, nothing else. You will hardly be able to argue with a “sound quality”. Just a myth and artificially created legend.
 

Brab

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Look - it might have been and should have been designed much much better, regardless there is Jam behind it. Flaws are unexplainable. We can see that most of the “legendary” designs and approaches were a bubble, just names, nothing else. You will hardly be able to argue with a “sound quality”. Just a myth and artificially created legend.
What a churlish reply.
 

KR500

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I thought I would post this to clarify things a bit. This was designed by Jam and not Nelson or myself. It also isn't the commercial version of the WHAMMY
Thanks for clarifying this Wayne.
We recently moved and I just finally got around to unpacking and setting up my WHAMMY and am enjoying listening to it
 

don'ttrustauthority

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Schiit's rejected design (due in part to lack of part availability) led to a 1000 unit release of their Magni 3(rejected) now called Piety by the company releasing it, Nitsch.

They are charging $149 and sold out in 12 hours, the 2nd harmonic is promised and measurements show delivered.

No power supply noise and slightly less money though.
 
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Pass makes Death and Black Metal sound disgusting. If any amp consistently makes a whole genre sound bad, the amp us worthless no matter the price.
Black metal is known for it's terrible quality, a lot of death isn't particularly well recorded either. You can't turn mutton into lamb and a badly recorded album will sound bad on any halfway transparent equipment. On the brightside there's lots of really high quality remasters coming out and labels are putting more of a priority on sound quality these days.
 

solderdude

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Schiit's rejected design (due in part to lack of part availability) led to a 1000 unit release of their Magni 3(rejected) now called Piety by the company releasing it, Nitsch.

They are charging $149 and sold out in 12 hours, the 2nd harmonic is promised and measurements show delivered.

No power supply noise and slightly less money though.

But it doesn't have the PASS logo, its small, doesn't have 2 inputs, and isn't expensive enough for people to connect their other expensive gear to.
Schiit pushes all the right buttons, small, good performance, cheap, lots of reviews etc.
 

Vacceo

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Black metal is known for it's terrible quality, a lot of death isn't particularly well recorded either. You can't turn mutton into lamb and a badly recorded album will sound bad on any halfway transparent equipment. On the brightside there's lots of really high quality remasters coming out and labels are putting more of a priority on sound quality these days.
Who said I expected anything other than a raw and crude sound? It may sound bad to you; I love Fallen Angel of Doom in a transparent system. A perfect example in that regard is Sodom's In the Sign of Evil, which to me sounds a lot better than the re-recorded Final Sign of Evil.

I like the old stuff precisely because it sounds harsh.
 
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Drakkar Noir

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final thoughts about the amp from the review unit owner:

* HEADPHONE JACK. Have to agree with Amir on this one. This issue was actually justified by Jam in some interview (don't recall which one), the locking jack being one that is proven to be very reliable; but still IMO looks a bit off in the otherwise expensive looking amp. Also, the reliability is from what I assume is its presence in instrument amps for musicians on tour. This is irrelevant for a HiFi audio setup.

* MEASSUREMENTS. While it's easy to understand the argument about Pass having deliberately implement some distortion in the amp to have a more pleasing, tube-like HiFi sound at the cost of ultimate fidelity, why not just use tubes? For tube sound I simply use my VERY tubby DNA.
Still, given the kind of music I listen to (Pearl Jam, The Strokes), this whole thing about measurements is kind of funny. As if a perfect headphone amp would fix rock recordings!

* AMP FEET. This hasn't been mentioned here yet. The amp was sent with felt feet and was a little slippery and annoying. Contacted Pass Labs about this, and they said they had rubber ones but changed them to felt because of the amp's weight and how it would leave marks or something. @amirm did you notice this?

* NO XLR. This is a non issue for me, as I explained earlier the RCA-only Pass complimented my setup perfectly. I know Nelson Pass uses something called Super Symmetry as a design approach, in paper it's supposed to be a balanced like connection without XLR. Makes no difference to me.
 
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