Pass Labs HPA-1 Loaner Program

Discussion in 'Sponsor Announcements and Deals' started by todd, Jan 18, 2016.
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  1. TMoney
    The HPA-1 sounds wonderful. You guys are in for a treat. The HPA-1 is a contender in the solid-state amp space.
    I haven't done any comparative listening with other amps yet, but that will come.
    If anyone is in the SF Bay Area and not on the list I will be bringing the amp with me to the meet in San Jose this Saturday, January 30th.
    I'll post a full review once my time is up.
  2. singleended58
    I am the last one in the list and located in SoCal.
    Thank you for the heads up!
  3. Todd Contributor
    A quick note on the Pass Labs HPA-1 - it was designed to operate on full time. No need to turn it off. It takes about 1 hour for it to warm up and start to reach its full potential.
    TTVJ Stay updated on TTVJ at their sponsor page on Head-Fi.

  4. TMoney
    My HPA-1 Review:
    With the marketplace for stereo and headphone gear as crowded and opaque as it has ever been, my philosophy has been to try and identify respected designers and companies whose philosophies and design values match my own.
    Though I’m not much of a DIY-er (beyond putting together amp-kits and re-terminating cables), my more DIY-savvy friends always rant and rave about Nelson Pass and his contributions to DIY audio. Mr. Pass’s designs are ubiquitous, and his candor, honesty, and intelligence are apparent to anyone who has read the white papers on the Pass DIY site. The Pass DIY white papers are so full of useful tidbits and insights that having read them you quickly come to respect respect Mr. Pass and his experience in the two channel audio world. Living in the Bay Area, I’ve met Mr. Pass a number of times at the Burning Amp Festival and I’ve always found him welcoming and happy to help and answer questions.
    Suffice it to say, I’m a fan of Pass Labs as a company. I own a Pass Labs XP-10 preamp and use it in my two channel setup. When I heard that Pass Labs was introducing the their first dedicated headphone amplifier I had to hear it. Thanks to Todd I was able to spend a week with the HPA-1 and got to use it in both my office and home rigs.
    Is a solid state amp the right choice for you?
    Before I go in to my impressions of the HPA-1, I want to take a step back and talk about sound signatures and pasta sauce. Why pasta sauce? Malcolm Gladwell gave a TED Talk about 10 years back ( where he talked about the perfect pasta sauce. It turns out that after analyzing data from massive taste tests that there is no such thing as a perfect pasta sauce. The pasta sauce taste test data clustered around different varieties. Some people really liked chunky pasta sauce, even though others didn’t. Some people liked their sauce spicy, even though others didn’t. Some like their plain, etc. Rather than there being a single perfect pasta sauce that would please everyone, the key to cracking the pasta sauce market turned out to be to offer all the different sauces different sauce varieties the taste testers clustered around.
    I think the market for amplifiers is like the market for pasta sauce. There just isn’t one amp that is going to satisfy everyone. Some people prefer the sound of OTL tube amps, some people like their amps to have transformer coupled output, some people are going to like solid state amps and some wont.
    To that end, I think the “solid state sound” isn’t for everyone. I’ve found that friends who listen to their music a lot louder than I do tend to hear solid state amps as “thin” sounding with too much or treble emphasis. I don’t hear solid state amps this way. What I want out of a good solid state amp is a “wire with gain.” I don’t want or expect added lushness or romance or a holographic soundstage. Just give me what is on the recording please!
    If you like the sound of solid state amps then you absolutely should try and audition the HPA-1.
    My Impressions.
    My overall impression is that the HPA-1 is solid state done well. I found the amp to be clear, neutral, and punchy. The HPA-1 is a very enjoyable listen, and I was able to listen for hours without my ears feeling fatigued. When I listened to the HPA-1 I wasn’t left wanting for more.
    I used the Sennheiser HD600/650/800 trinity of headphones to evaluate HPA-1. In my experience, the Sennheiser trinity are as adept as any current production headphones at revealing the character of the amps that power them. I thought the HPA-1 was an excellent match for the HD600/650/800 trinity. While I didn’t use any planars or IEMs in my evaluation, the HPA-1 has a low output impedance and high power output so I don’t imagine it’d have any trouble getting the best out of just about any headphone.
    During my evaluation I mostly listened to jazz, classical and well recorded classic rock. I used the Schiit Yggdrasil DAC (via USB) and the OPPO BDP-105 (playing SACDs) as sources. The HPA-1 did well with everything I threw at it. Newer, “hotter” recordings with less dynamic range didn’t sound so great, but the only conclusion I draw from that is that the HPA-1 doesn’t “lush up” the music. I think that is a good thing.
    I could easily live with the HPA-1 as my only amp.
    Comparisons with other amps.
    I was able to compare the HPA-1 closely with my Bottlehead Crack-a-two-a and a DIY SuSy Dynalo I had on had.
    With regards to the Crack 2, the two amps sound very different. The Crack 2 is more forgiving than the HPA-1 and tonally sits on the “warmer” side of neutral. By “warmer” I mean that the Crack 2 tilts towards the bass and low-mids rather than treble. The Crack 2 also has more quantity of bass, even if it is less controlled than the bass on the HPA-1. The HPA-1 sounds more neutral and clear. The HPA-1’s bass is punchier and better controlled. While the Crack 2 is the more fun, relaxing amp, the HPA-1 feels a lot more accurate and honest to the recording. While I personally would choose the HPA-1 over the Crack 2, I can easily understand fans of OTL tube amps doing the opposite.
    I heard much less of a difference between the HPA-1 and the DIY SuSy Dynalo. Both seemed to me to be well designed solid state amps and both predominantly have the “wire with gain” character I look for in solid state. Both sounded clear, neutral and punchy. In fact, the amps sounded close enough that I had a hard time telling them apart. That is a good thing as I liked both the HPA-1 and SuSy Dynalo quite a bit. In a comparison under meet conditions I heard the HPA-1 as being the slightly more powerful amp of the two with better control down low and a slightly bigger soundstage, but the room was noisy and the differences between the two amps could just as easily fall in the margin or error that exists while trying to do comparisons at a headphone meet. Honestly, I’d be happy having either amp in my stable.
    Build Quality.
    The build quality of the HPA-1 is fantastic, with one notable caveat. I think the TRS jack on the front was a poor choice and looks bad on an otherwise gorgeous amp. With that sole exception, the amp is a stunner in person. The HPA-1 looks and feels like a solid piece of kit and looks much better in person than it does in photos. Like my Pass Labs preamp, the tactile sensation of operating the volume knobs and inputs is absolutely top notch. I thought the HPA-1 looked and fit great as part of a desktop rig.
    For an amp that costs as much as the HPA-1, it’d be nice if it was fully balanced. At the very least I think the HPA-1 should have had a balanced input option despite only being a single-ended output. I am also not sure why preamp functionality was included on the HPA-1 as I would never consider using it as a preamp without a remote. A remote would have been a nice addition with the HPA-1.
    The other big con of the HPA-1 is its price. Value is in the eye of the beholder, but to me I think the amp is a bit too expensive. I’d strongly consider purchasing the HPA-1 for myself if it fell in the $2,000-$2,500 price range. At $3,500, it is a bit tougher for me justify.
    The Pass Labs HPA-1 is a very solid debut from Pass Labs. To my ears it is a well executed solid state amp. The HPA-1 sounds clear, punchy and neutral. It was a very nice pairing with the Sennheiser HD600/650/800 trinity and should be flexible enough to bring the best out of most current production headphones. I could live with the HPA-1 as my only amp, especially if it wasn’t quite so expensive. Fans of solid state amps should definitely give this one a listen.
  5. jp11801 Contributor
    First off props to TMoney for the excellent write up on the Pass Labs HPA-1 as it mirrors many of my thoughts on the amp.

    I have been through an multitude of headphone amps and audio gear in general since joining Head-Fi a decade ago. The one thing that has struck me is the growth in the top end segment (summit gear) and our communities struggle with the exponential growth in cost for some gear and the misunderstanding that cost increase is not linear with sonic benefits. First off cost increase s objective there is no disputing that a $1000 amp is twice as much as a $500 amp. Sonic benefit is much harder to pin down as one person's 10% sonic increase could be another persons 50% sonic gains. That said I am generally happy to see statement the growth in both statement type gear and many traditional (two channel speaker manufactures) audio companies taking an interest in our hobby.

    Today I own the Schiit MJ2, a SinglePower MPX3 (toaster version and a nod to the Head-Fi of old) and a DIY Fet based amp called the Fetastic amp (this was a DIY project that another member that I respect immensely put together for me). While I hate to start at the conclusion sonically the Pass Labs HPA-1 bested each of the current amps in my stable.

    Headphones that were used during the loaner period were the Audeze LCD-X with Moon Audio Silver Dragon cables, Audio Technica W3000 Anv and the Audio Technica AD2000x. The Audeze LCD-X are my go to headphone as they IMHO do so many things well and have few deal killers for me sonically. The Audio Technica headphones are more of a one again off again love affair. They can really get to the emotion of the music in a way that even the great LCD-X can't but they are very picky with headphone amps.

    Lastly my preference is for a clear sound and find quick transient response, dynamics , detail (think hearing decay, room sounds, reverb trails) and realistic tone/timbre to be characteristics that I look for in audio gear.

    Fit - Finish and initial visual impressions - The box and amp was somewhat smaller than I had anticipated. While not a small amp by any measure it is not a full sized rack space amp. The amp clearly shares the Pass aesthetic clean lines, solid as tank and great looking in that school of design. I will say the headphone jack, a locking variety takes away from some of the clean appearance and initially is a little of a pita. Once you get used to swapping out gear the jack is less of an inconvenience but still visually detracts from the amp. The input switching and pre amp selection is well done and appears to be an electronic relay rather than a mechanical device.

    Impressions - This amp does what many solid state and hybrid (tube input and SS output) amps fail to do it portrays the music in a detailed way without a thinness or dry character that I have heard even in some of the better SS or hybrid amps. I found the amp to portray detail and transients extremely well while also being on the warmer sounding side of SS amps I have heard. The amp absolutely excels at portraying realistic tone and I was continuously impressed with this aspect of the HPA-1 during my time with it.

    LCD-X this amp did a good job with these cans but I would say that I have not found these to be super picky headphones. The HPA-1 outperformed the Schiit and other amps in my possession but not significantly with these headphones. The HPA-1 presented a better width and depth of head stage than the MJ2 and was better in tone (but not by a wide margin). I would be interested with a longer time frame impression between the two as I do find that long term listening then switching to be far more reliable than quick switching impressions. I did a bit of both with these but more time may have benefited the distance between these two amps.

    Audio Technica W3000 ANV - These are beautiful headphones and I have bought these twice as I sold my first pair but missed them so much I tracked down another pair. These when amped right can be down right addictive and can emotionally couple me to the music in a way most headphones simply can not. I had these up for sale while I had the HPA-1 in the house and based on how great the W3000s responded to the HPA-1 I pulled these from the for sale forum. If I were a W3000 owner and favored a solid state single ended design amp this amp would be on my very short list and at the top. I found myself more often than with any other amp in my collection smiling an tapping my feet when listening with the W3000 through the HPA-1. Great tone, warm sounding but also very detailed and great transient response. This combo is downright enjoyable and highly recommended.

    Audio Technica AD2000x - Another great combo and really fantastic bass response with this combo far better than the other amps in my possession. Many of the W3000 improvements I heard were echoed by this combo. Not quite as subjectively enjoyable than the W3000 but none the less one that I reached for over the week I spent with the amp.

    Overall I really liked this amp myself trying to steal away as much time as a I could during a very busy work week to enjoy my time with the HPA-1. Now at this price point I do prefer a few more options like balanced inputs, balanced headphone outs and even a balanced pre out (I have genelec 8050 monitors that I would have loved to try with this amp. While the Pass HPA-1 may not be a "value" amp from a cost to subjective sonics standpoint it is a great solid state amp.

    I strongly recommend anyone in the market for a Summit - Fi SS amp audition the Pass Labs HPA-1.
    TMoney likes this.
  6. SupaFuzz
    Thanks for the reviews guys - keep 'em coming!!
  7. musicman59
    I just picked up the amp from UPS on Wednesday night. I will be making a direct comparison to my McIntosh MHA100 using the HE1000/Vero Reference cable, McIntosh MHP1000/Vero Reference cable, Ether C WireWorld Nano Silver Eclipse cable, HD800 Zeus OCC Copper cable and W3000ANV stock.

    Will report back sometime next week.
    AFWannabe likes this.
  8. TMoney
    I'll be looking forward to hearing your impressions, MM.
  9. musicman59
    I had the opportunity to spend some time with the new Pass Labs HPA-1 thanks to Todd from TTVJ.
    I have been a big fan of Nelson Pass designs since I was introduced to them when I bought the original Adcom GFA-555 back in the 80s. Yes, that original GFA-555 was designed by Nelson Pass.
    Do you remember the brand of car audio Soundstream? Well, their award winning D200 amplifier was also a Nelson Pass design and guess what I also bought it.
    The in the early 90s I discovered and was able to afford the legendary Threshold brand so I bought a FET TENe Preamp and a S550e amplifier (which I still have). Then about 3 years ago or so I bought an Aleph 3 to drive a pair of HE-6 headphones and to be honest I have never heard the HE-6 sound so good than with that little amp so when I saw that Pass Labs was coming out with a headphones amplifier I got really excited and my expectations went through the roof.
    When I realized the HPA-1 was not really a Nelson Pass design I got a little disappointed but heck it is a Pass Labs so it must have its linage, right?
    As mentioned here before, the amp is very well built and aesthetically it resembles the Pass Labs line. The unit is simple, solid and elegant. There are only two things that I personally don’t like. The first one is the ¼” socket. I personally think it clashes with the face plate design and the fact that is a locking socket in my opinion makes it a pain in the rear when switching headphones. I think a more simple and not distracting piece would had worked better with the cleanliness and elegance of the face plate. The other thing that does not make sense to me is the preamplifier output. I really don’t see many people buying a HPA-1 and use it as preamp. People buying a headphones amplifier of this level either are focus on just Head-Fi or is they have a speaker system most likely will have a much better preamp anyway.
    The source for my listening sessions was my Mac Mini dedicated server. This is a late 2009 Mac Mini server version with a 120Gb SSD for the software and a 1TB HDD for the music files. It has a Mojo Audio LPS and runs JRiver’s latest version. It is connected to a REGEN using a WireWorld Platinum Starlight USB cable and the REGEN is directly connected to my Bricasti M1 Special Edition DAC. The cables form the M1 output to the HPA-1 are WireWorld Eclipse 6 and the power cords used for all the equipment are WireWorld Electra. By the way, the power is supply by a dedicated AC line.
    The headphones used were: HiFiMan HE1000 with MIT Vero Reference cable, McIntosh MHP-1000 with MIT Vero Reference cable, Sennheiser HD800 with Zeus OCC Copper cable, Mr. Speakers Ether C with WireWorld Silver Nano Eclipse cable and Audiotechinca ATH-W3000ANV in stock mode.
    The HPA-1 was evaluated using all the headphones and comparing it also to a McIntosh MHA-100 amplifier.
    The HPA-1 is design to stay on all the time. The only on/off switch is a rocking switch at the back of the amplifier. At the front it has a dimmed blue light which is not distracting at all to indicate the unit is energized.
    The first headphones used were the HE-1000. The sound character is on the warm side of solid state. This warmer sound gives me the sense of a cozier environment but the level of detail is not lost at all. It provides the kind of sound that allow you to have long listening sessions with no fatigue at all. One thing that concerned me was that in order to get the volume level I use to listen I had to turn the volume knob between 2 and 3 O’clock. Compared to the MHA-100 the McIntosh is more transparent and because of that it seems more detailed even that the Pass is not lacking of it. Also in the MHA-100 I just go up to about 40% of the volume knob to reach the same level as the Pass.
    The next headphones to try were the McIntosh MHP-1000 and then the HD800. In both cases the results were similar to the one form the HE-1000.
    The change came when I tried the Ether C and the W3000ANV. With both of these headphones the Pass did a spectacular job. The volume knob went just up to 11 O’clock to get my desire sound level and the presentation of the sound was much coherent and musical. In fact that was the best time I have heard the Ether C and the W3000ANV. This result leads me to believe that the HPA-1 matches better with low impedance and easier to drive headphones due to its power level.
    To be honest I was not expecting the results I got. My expectation was an amplifier with guts and power to drive and controlled any headphones you throw at it but it is clear to me and in order to perform to its best it needs to be paired with low impedance and high efficiency headphones. With the rest will perform ok but its best.
    The HPA-1 delivers 3.5 watts @ 20 ohms. I wish Pass had designed it at those 3.5 watts but @ 40 ohms at least.
    jazzfan, AFWannabe and HemiSam like this.
  10. mkarikom
    This is a review of the Pass Labs HPA-1 headphone amplifier which was generously provided by Todd at TTVJ.  Over the past week I have auditioned this amp with the following components:
    Audeze LCD-2 (hp)
    Resonessence Concero HD (DAC)
    Niles AXP-1 (passive input selector)
    Macbook Pro (transport running Audirvana Plus, mounted SMB storage)
    The HPA-1 has 2 pairs of RCA inputs on the back panel and one pair of RCA pre-amp outputs.  The case work on this amp is impressive.  Its face plate is a half inch of solid aluminum.
        The tuning of this amp is outstanding.  Overall it is warm and detailed with especially good presentation of mids and highs.  Not surprisingly the HPA-1 provided a particularly engaging dissection of vocals and piano on Tori Amos' "Mother".  This amp did a great job resolving the complex instrumentals of Amon Tobin's "Slowly".  This track layers a variety of heavily distorted acoustic sources in such a way that audio systems are challenged to reveal them against a prominent guitar dub which has a tendency to bloom.  Moving on to EDM, the HPA-1 destroyed Boys Noize' "Out of the Black, The Remixes" album from end to end.  In particular, the hammering 5-10khz staccato of Errorsmith & Fiedel's XTC remix was positively euphonic.  
        Using the AXP-1, I was able to A/B the HPA-1 against my Violectric HPA V200 with source selection taking about half a second.  Although peak output of the HPA-1 is at least 30% greater than the peak output of the V200, I'm not sure how this effects the differences that I heard between the two.  I would say that the most prominent achievement of the HPA-1 with respect to the V200 is a smoother yet more authoritative mid-range.
        The HPA-1 is fine amplifier.  At the moment I have no use for its pre-amp functionality, but I still consider that a selling point since my minimal desktop system will most certainly include a set of bookshelf speakers and a modest power amp at some point.  In hindsight, this audition is somewhat hampered by the fact that my LCD-2 is easy enough to drive that the HPA-1's insane power output was not sufficiently tested.
  11. Todd Contributor
    Hi All,
    The Pass Labs HPA-1 is on its way back to me. Everyone who signed up for the program has had their turn with it. If you are seriously interested in purchasing the Pass Labs HPA-1 you can call or email me (do not PM me as I may not see it!!!) and we can arrange an in home audition. For that you will have to pay shipping costs both ways but if you buy one you will get free shipping and a credit for your shipping costs.
    TTVJ Stay updated on TTVJ at their sponsor page on Head-Fi.

  12. TMoney
    Thanks again for putting the HPA-1 loaner program together, @Todd!
  13. Frihed89
    Buy/make a speaker to headphone adapter and hook it up to any FirstWatt amplifier.
  14. a1uc
    Looking at either getting a HPA-1 or Master 9 anyone
    hear both ? I'm trying a First Watt J2 now
  15. musicman59
    A friend of mine has the Master 9 and have listened to it a few times with my headphones. I really like it and can drive anything.
    I had the HPA-1 in my house as a loaner. I have to say I have been a Nelson Pass admirer since the early 80s so I was very exited when I saw a headphones amp coming out. I personally was disappointed with it. First, it is not a Nelson Pass design and second it sounds nice with easy to drive headphones (like the W3000 ANV) but to me it struggles with harder to drive headphones.
    If I was buying I would go with the Master 9.
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