[adydula]

Why thanks Drift....and you have a nice day...back to listening with one of the best head amps in the world....and when u have some free time...not trolling send Nelson Pass a note and tell them this amp is to heavy for you....I am sure they will like that input.

 

[paradoxper]

It's already the least expensive product they make, so maybe they're not looking to go too far "down" market and erode the hi end perception of their brand. It could certainly open up their brand to so many others and possibly be the gateway for others to their other products. Based on sound quality, I think most of this thread have found it worth the price of admission. I do also wish the HPA-1 would get more attention (I tried reviving the HPA-1 thread here on headfi just a week or two before Alex posted his review, but almost no responses).

For power hungry headphones, I've been raving about the Pass XA25 speaker amp, but it even works great with HPs with lower power requirements if you can manage the gain (it's also the quietest amp that Pass makes with only 50uv of noise. My X150.5 had 200uv of noise and it was intrusively audible on all but my least sensitive HPs). I'm using an XP-12 preamp now, but I really should try out the line stage in the HPA-1. To my ears the HPA-1 is more neutral than the XP-12/XA2 (Personally, I prefer a a bit of warmth).

It's also a new market for them. I surmise this won't be Nelson's avenue. Though I've really enjoyed his supersymmetry design -- notably outstanding in the INT-150 and Xs 300 along with SuSy Dynahi and switchable in my CFA3.

I also favored the INT-150 over the XA25 for the TC. Although I do agree, I like the XA25 with separate preamp duties for other headphones.

It makes sense the HPA-1 would serve as the perfect gateway.

 

[driftingbunnies]

Why thanks Drift....and you have a nice day...back to listening with one of the best head amps in the world....and when u have some free time...not trolling send Nelson Pass a note and tell them this amp is to heavy for you....I am sure they will like that input.

I don't think they'll believe me when I say it's too heavy for me and explain that my current amp is 29 lbs.

 

[adydula]

So for a few months now with the HPA-1 I can honestly say its one of the best amps I have ever used.....simply never fails to astonish me with its overall performance with most any headphone I have.

Lately the HEDD's which can stand a bit of power to excite....its a wonderful match...I remember speaking to Klaus and Freddie directly and they stating anywhere from 1-5 watts should drive the HEDDS rather well...with the HPA-1 spec'ing at approx 3.5 watts RMS its indeed in that sweet spot range.

I know its a $3500 retail amp, and not many would spent there hard earned dollars on such an expensive amp. There are many other good choices put there for less money like the Schiit Jot 2 IMO...which I have as well.

But the HPA1 has a very distinct musical presentation and has a wonderful slightly warm side to it...but very clear, clean and crisp as well.. spent a few hours listening to some live concerts, like Carole King's Tapestry Live at Hyde Park...and the experience is a 10/10///a wonderful example of all around excellence...

Would I buy this amp again, in a heart beat....no frills...no VU meters, no crossfeed, Class A all the way, SE only, no need for balanced, It just amplifies very, very well.

Alex
:>)

 

[Justin_Time]

The Pass Labs HPA-1 is the best sounding SS amp I own. The GS-X Mk2 held that position for a very long time but the HPA-1 sounds cleaner, more neutral, more accurate overall without being too analytical or sterile. In comparison, the GS-X Mk2 sounds warmer but more colored in the midrange and falls short of the uncanny ability of the HPA -1 to retrieve subtle details in the music. The GS-X Mk2 is a good match, however, for HP like the Sennheiser HD-800S; it adds a much needed warmth to the HD-800S lean sound. In contrast, the HPA-1 reveal the flaws in the HD-800 sound rather than covering it up. I also wished just a bit more power with the HPA-1, perhaps enough to properly drive the often under-appreciated HiFiMan HE-6. But Nelson Pass’s approach has always been for simple designs with as few as possible active components in the signal path and minimal negative feedback. And a more powerful balanced design, for example would raise the price significantly.

Talking about price. I for one do not think that the HPA-1 is over-price considering what I get in terms of sound quality. As a matter of fact, Nelson Pass’s amps, from the venerable Threshold in the 1980s to the Pass Aleph, the First Watt and the latest,Pass Labs, have not usually been viewed as overpriced considering what they give in sound quality. There are many other names in high-end audio that priced their amps far above Pass’s. In personal,audio, many tube amps that have competitive sound with the HPA-1 such as the Woo WA5, Manley Absolute amp, EAR HPA-1, Apex Teton and Pinnacle are all priced above or well above the Pass Labs HPA-1. As a matter of fact, the prices of headphone amplifiers have not (yet) undergone the ridiculous and insane price inflation of the headphones and IEMs.

To me, the Pass Labs HPA -1 is a great amps, a good value and a keeper.

 

[adydula]

I cant agree with you more....its a very, very special amp for sure.

There has been some talk of a balanced version that would have more power and would probably cost twice as much...for me its fine as is.
I dont have any desire for the HE6se or a Susvara at the moment...

The only headphone I have that is not super efficient are the HEDD's...which the HPA-1 drives rather well.

Alex

 

[adydula]

Recently I acquired a pair of HD650's, new....and the pairing with the HPA1 is EXCELLENT scales up wonderfully...good bass and excellent mids and the soundstage opens up nicely...surprisingly so...this oldie is an excellent CD to show this synergy very well!

 

[Jedclampet]

Thanks for the review this amp is on my short list and I have a question with compatibility with Abyss Diana Phi.
Has anyone out any feedback?

 

[adydula]

My HPA1 drive my Hedds rather well...these are :

Efficiency	87 dB SPL for 1 mW
Impedance	42 Ω

Abyss Diana specs

• Impedance 42 ohms
• Sensitivity 91 dB/mw

Should be just fine. They are easier to drive than the HEDDS.

 

[ThanatosVI]

My HPA1 drive my Hedds rather well...these are :

Efficiency	87 dB SPL for 1 mW
Impedance	42 Ω

Abyss Diana specs

• Impedance 42 ohms
• Sensitivity 91 dB/mw

Should be just fine. They are easier to drive than the HEDDS.

Actually eing able to drive the HEDDS means it's able to drive basically anything.

 

[adydula]

It might struggle a bit with the ABYSS 1266 or Susvaras..its all subjective....as well.
What I call drives well might not sit well with others!!
LOL

TBH its a great amp and should drive the Dianas rather well..

 

[Jedclampet]

I was also eyeing the Eleven Audio Broadway Balanced that Abyss seems to think is a good match, any thoughts.
I haven't seen much feedback here on that one or a review.

 

[Justin_Time]

I have owned many SS amps, too many to remember them all. The two top performers with the vast variety of headphones out there are the GS-X Mk2 and the Pass Labs HPA-1. The HPA-1 has only two limitations that I know of. It is a little short on power to drive the ridiculously inefficient HiFiMan HE-6SE to its fullest capability, more of a problem with the HP than with the amp. Being very neutral and revealing, the HPA-1 also lays bare the two main flaws of the HD-800 and HD-800S: insufficient bass volume and over-generous treble energy. The HPA-1 works very well with 20 or so other pairs HPs I have owned. The Diana 2 should not be an exception. Few SS headphone amps are as neutral, clean and versatile as the HPA-1.

 

[Jedclampet]

In my main system is the Pass Labs INT 30 class A all the way yet the HPA-1 has a different designer would you suppose that it might have the same sound signature.
Borderline tube like?

 

[Justin_Time]

If you work at Pass Labs, you cannot help but adopting Nelson Pass’ design philosophy: class A, simple design, minimal number of gain stage, minimal number of active components in the signal path, minimal to no negative feedback.

I have owned most of Pass’s amps, from the Threshold to the Pass Aleph, the First Watt and the Pass Labs XA series. They do share a family sound which is not the typical transistors sound. The Pass,sound is smooth, transparent, articulate but above all utterly musical and without any of the analytical, sterile tendency of many SS designs. But neither is it like a tube sound as it does not have the euphonic midrange nor the slightly fat bottom of many tube amps. The Pass amps have their own unique sonic signature.

it was very educational to compare the sound of the HPA-1 to that of the GS-X Mk2, another good SS amp, and to the sound of a few of tube amps like the Apex,Pinnacle, the Feliks Euforia AE or the Woo WA5. With an excellent but flawed HP like the Sennheiser HD-800, the HPA-1 reveals the true sound of these headphones, warts and all. The soundstage is expansive. The midrange is utterly clean and smooth, but the bottom end is anemic and the treble shows too much energy. The GS-X Mk2 adds sweet caramel to the midrange and softens the treble a little making the HD-800 sound more listenable. These are good colorations, but they are colorations nevertheless. The tube amps sweeten the midrange even further while losing some of the inner details in the process. They sweeten the top end as well and add a whole lot of fat to the bottom. The overall sound is more balanced, more pleasant and more enjoyable than the honest sound of the HD-800 as revealed by the HPA-1.

In short, being a transparent and neutral amp, the HPA-1 will not cover up or help correct the flaws of some headphones like the HD-800. But with outstanding HPs like the Focal Utopia, HiFiMan HE-1000SE, Audeze LCD-4Z, or ZMF Verite, the performance of the HPA-1 is nothing short of astounding!