Wow... do I LOVE these headphones!

OK... back up a bit. I have or have had about 70 pairs of headphones, ranging from the top-end but dated HiFiMAN HE1000 (superseded by the HE1000 v.2), the classic Sennheiser HD800 (no, not the more recent HD800s), the Fostex TH900, and every Grado known, from the new PS2000e and GS2000e through the entry-level SR60 and iGrado, and back to the historical classic Joseph Grado HP1000 (HP1).

Based on the most disparaging review here, I HAD to get the Ultrasone Edition 10, as I have found on multiple occasions that my tastes are diametrically opposed to that reviewer's (you see, his good, such as the NAD hp50, and his bad, such as any Grado, are my bad and good respectively).

With the background of headphones ranging from retro to modern, cheap to expensive, bassy to bright, tortuous to luxuriant, and ugly to beautiful), my Ultrasone Edition 10s occupy their own special unique place in my lineup.

Bright? Absolutely! Brightest I have? Yes. Painfully sibilant? Absolutely not.

The Edition 10s give me a new perspective on my music, not found with my any of other headphones. I hear things I have never heard, and I hear familiar music in a new and exciting way. More than any headphone except maybe my HE1000s, I find it difficult to tear myself away from listening with them.

Their brightness illuminates unheard aspects of my music. Their subbass, while not as strong as my Sony MDR-Z7's, simultaneously reminds me of the low bass line that I discovered with the Z7s, and most of all... the layering! That sonic imaging... that positioning. There is a spatial aspect to the music that I first heard (and until these Ultrasone Edition 10s, ONLY heard) with my new Grado PS2000e in balanced configuration.

Oh, and they are beautiful in appearance and comfortable in use. The grills on the earspeakers remind us of the veins on the butterfly wing; the "Y" of wood in the middle is exactly mimicked in shape by the wood stand that is included. The earcups are big enough for your ears and the headphone is surprisingly light to wear. I became a fan of Ultrasone with their closed Edition 8s (Ruthenium); I am confirmed a fan by these (open) Edition 10s.

CAVEAT! head-fi.org crashed and trashed my review when 90% in and offered no way to reconstruct. This iteration is being entered incrementally and may not be complete. Instructions give a minimum, but not a maximum, limit.

ABSTRACT

The black Chord Hugo 2 was received on loan as part of the Official Chord Hugo2 Canada/U.S.A. Tour, described here. In short... I'M SOLD! Chord has taken an exquisite product, the Hugo, improved its sound, and even more so, improved the quirkiness that Hugo owners had to endure for the pleasure of using the Hugo.

PHYSICAL/ELECTRICAL COMPARISON TO HUGO 1

The Chord Hugo 2 is very slightly larger (broader) and heavier than the Hugo 1. The following pictures compare the two Hugos.


Fig. 1: Chord Hugo 2 (black, bottom) moves many of the lights and switches scattered around the Chord Hugo 1 (silver, top) to a neat row.


Fig. 2: Chord Hugo 2 (black) is about 1/8" wider than Hugo 1 (silver) and has sharp, rather than rounded, edges and corners. Connectors on the Hugo 2 are flush with the surface of the chassis, rather than recessed as on the Hugo 1, and power is provided by a standard USB charging port on the Hugo 2, rather than a round wall wart plug.


Fig. 3: Chassis openings around the jacks on the Hugo 2 (black) provide enough clearance for most large-ended jacks, unlike the Hugo 1. Special cables are no longer needed for the Hugo 2.


Fig. 4: The Bluetooth port on the Hugo 2 (black) is larger and more sensitive than on the Hugo 1, allowing operation from across the room.

Fig. 5: The Chord Hugo 2 fits, though tightly, into the Chord Hugo case designed for the Hugo 1. Both the greater width and the raised volume control surround make the fit into the case tight.

Fig 6: The new design of the buttons/lights on the Hugo 2 allow in-case access by simply pressing the edge of the case.

There are a number of improvements in convenience that the Hugo 2 makes over the Hugo 1. Indeed, to my mind these are even more of an improvement in the Hugo design than the improved sound. The differences of the Hugo 2 include:

1. Easier "On/Off" switch... a simple finger-sized button rather than a recessed microswitch requiring a fingernail;
2. All jacks are at the surface of the chassis, rather than buried deep into a recess. Hence, the cables with special small ends that Hugo owners have had to buy are no longer needed for the Hugo 2;
3. USB ports are inverted in position;
4. Optical connector opening is covered (and not recessed);
5. Volume control and its surrounding housing protrude a bit from the chassis, rather than being flush, and the volume control ball is bigger;
6. Hugo 2 is 1/16" thinner, 1/8" wider, and 1.25 oz heavier (13.5 oz vs. 12.25 oz) than the Hugo 1;
7. Hugo 2 has sharp corners and edges; those on Hugo 1 are rounded;
8. Hugo 2 adds a four-position switch to tailor the reconstruction filter. The Hugo is known for its long reconstruction filter, said to be key to its sound, particularly for transients. The original Hugo had a filter of over 26,000 taps, while the Hugo 2 has over 49,000 taps. This switch adjusts the high frequency roll-off of the filter (little difference in sound as far as I could tell);
9. Charging proceeds through a standard USB port rather than a dedicated wall wart and round plug that the Hugo 1 has;
10. USB input is only one jack, combining the driverless USB (for tablets/phones) with the high-data-rate driver USB plugs on the Hugo 1;
11. Coax input is unfamiliar, at least to me... instead of the standard RCA input of the Hugo 1, the Hugo 2 uses a multi-ring miniplug, and figuring out polarity from the coax output of the FiiO X5ii player used below was hard;
12. Hugo 2 has a remote control, aiding its use in a desktop system;
13. Hugo 2 has a charge-while-running operation and intelligent charging system, again to help use in constantly-plugged in desktop systems.
14. Bluetooth receiver of the Hugo 2 is more sensitive, supporting longer-range, across-the-room usage (rather than the close-in, airplane-mode-friendly short distance of the Hugo 1).

SOUND

I have performed three types of tests:

1. Three-way comparison of the Hugo 2 to the Hugo 1 and iPod Touch 6 Gen, and three way comparison of the Hugo 2 to the Lotoo PAW Gold digital audio player and the Schiit Bifrost Multibit DAC with Schiit Lyr 2 amp;
2. Blind test, using a second person more skilled than I in hearing subtle differences;
3. Variety test, using several different headphones, music types, and bit rates to determine whether preferences of the Hugo 2 vs. the Hugo 1 maintain in the face of these changes.

It is perhaps interesting to review the current prices on many of these systems discussed here:

• Chord Hugo 2 - $2195 (Moon Audio)
• Chord Hugo (1) - $1,995 (Moon Audio)
• Lotoo PAW Gold - $2,399 (Diane Edition - The Evolution of Sound)
• Schiit Bifrost Multibit & Lyr 2 - $1,048 (Schiit Audio)
• Apple iPod Touch Gen 6 - $399 (Apple)

THREE WAY COMPARISON TEST - METHOD

I have used this test method many, many times on many headphones, as can be seen by the tables here and the links to over 50 individual tests therein.

I used four songs, all encoded in Apple Lossless Format at CD quality (I actually bought the CDs and ripped them... no internet download involved) and played by my Apple iPod Touch 5th Gen. Because each of the 10 acoustic tests used a limited segment of music (2 - 10 sec), an infinite loop was used to repeat the appropriate segment of each song while DACs were switched in and out.

• "You're Going To Miss Me When I'm Gone," by Band of Heathens, from their album One Foot In The Ether (used for fidelity of drum sound, positional resolution of two vocalists, and ability to discern pitch of string bass passages);
• "Spanish Harlem," by Rebecca Pidgeon, on The Ultimate Demonstration Disc of Chesky records (used to assess female vocals, transparency, the attack of finger on bass string, and high resolution discrimination of differences in shaker shakes);
• "Symphony No. 3 in C Minor Op. 78 (Organ Symphony) - IV" by Camille Saint Saens played by Lorin Maazel and the Pittsburgh Symphony Orchestra (used to assess the "ripping" sound of well-rendered lower brass and organ reed pipes, and the ability to hear a very small entrance amidst a bombastic chord of orchestra and organ at full tilt);
• "Throwback" by B.o.B. on Underground Luxury (used to assess ability of a bass tone, specifically lowest C on piano at about 32 Hz, to pick me up by the throat and shake me!)

The 10 tests were as follows:

• Transparency: What is between me and the music? A felt cloth? A "Sennheiser veil?" A frosted window? Dirty window? Clear Saran wrap? or nothing? At its best, makes me forget I am listening on headphones and am in room with musicians. [I use the 12-second segment 0:00 - 0:12 of "You're Going To Miss Me," which is kick drum, guitar, piano, and cymbal for this test]
• Width of sound stage: How far to the left and to the right, (yes, AND up and down in best cases) does it seem the musical sources are arranged? [I use the same 0:00 - 0:12 segment of "You're Going To Miss Me," which starts with kick drum center, guitar #1 right of center piano far right, guitar #2 far left, to see 1) to what extent am I among rather than in front of the musicians, and 2) how wide an angle do those positional extremes of instruments form?]
• Positional resolution: Can I distinguish a difference in position of two singers in Song 1? [I use 0:30 to 0:38 of "You're Going To Miss Me," where one vocalist ends a verse and a second vocalist, standing next to him, takes up the next.]
• Bass visceral: Does the bass in third verse of Song 4 actually shake me? Or do I just hear it? [This test uses 0:31 through 0:33 of "Throwback, " where the bass drops to the lowest C on the piano.]
• Drum "twang": At start of Song 1, do the bass and tom tom drumhead have a tone and a pitch, rather than just a thump? ["You're Going to Miss Me" 0:00 - 0:12]
• Bass pitch perception: For the complicated bass runs in Song 1, do I hear a pitch with sufficient accuracy to sing or transcribe the part? ["You're Going to Miss Me," 1:02 - 1:23 to see if I can hear the pitch of not only the bass glides and accented notes, but also the grace notes]
• Bass finger pluck: Do I hear the actual impact of fingers on the bass string just before hearing its sound on Song 2? ["Spanish Harlem," 0:00 - 0:04, listening most carefully to the repeated 3-note pattern to see if I not only hear an initial attack but some structure immediately following, before the finger leaves the string and the sound just rings)
• Shaker variation: In Song 2, verse 3, do the various shaker shakes sound a bit different from each other, as they should? ["Spanish Harlem," 1:40 - 1:47: there are clearly loud and soft shakes, but how many more volume levels of shakes can I distinguish, and can I hear structure within each shake as the seeds hit the shaker wall?]
• "Ripping" of organ / brass: In Song 3, is there the sensation of hearing each vibration of the French horn and low organ reed tones (sort of the tonal counterpart to hearing a "pitch" from a drumhead in Test 5); ["Organ Symphony," initial chord from 0:00 - 0:04 and French horn passage 0:06 - 0:12]
• Discern added chord: About 1:38 into Song 3, after the full orchestra and organ hold a chord at the top of a passage, can I hear a small number of orchestra instruments join in, as sort of an echo, in the second measure of that chord? ["Organ Symphony," in the passage starting at 1:08, how well can I hear the small additional chord added at 1:16 on top of the full strength organ/orchestra chord in progress? Clearly enough to have noticed it if I weren't already listening for it?]

THREE WAY COMPARISON TEST - RESULTS

The table below gives a first place (blue, 3 points), second place (red, 2 points) and third place (yellow, 1 point) rating to each of the three systems compared to one another on each of the 10 tests. Just for fun (nearly meaningless, though, for supreme-level systems such as these), I added the points across all 10 tests to see which was overall highest scoring, second, and third. Since these are rank orders rather than absolute scores, and since I can make mistakes in comparison (though I tried to assure that any differences I declared were large enough that if made to repeat in a blind test, I could... hence, there is at least one feature that has a three-way tie), scores of 3 or larger are significant.

I used the HiFiMAN HE1000 as the headphone in the following test, because earlier tests of other DACs showed me that it was the most sensitive of my headphones to differences in DACs. Here is the result of comparing the Hugo 2 (center column) to the Hugo 1 (left) and iPod Touch 6 (right):

Fig. 7: Hugo 2 (center) outshines the Hugo 1 and iPod Touch 6 in areas of treble detail and sound stage; Hugo 1 and iPod Touch 6 were comparable in total score, though different in strengths.

The similarity of the iPod Touch 6 to the Hugo 1 has been the subject of multiple threads (here and here), with opinions ranging from "I can't tell the difference, either" to "I hear a clear difference on all music" (and I fear an unspoken "What's wrong with you?") .

As I am an aficionado of Grado headphones (I have over 25 pairs!), I have often talked with Grado Labs, and they have recommended both the Schiit Lyr 2 and the Lotoo PAW Gold as excellent for Grado headphones. Hence, I compared these two systems with the Hugo 2 in driving the Grado PS1000e headphone, as follows:


Fig. 8: Lotoo PAW Gold provides slightly better sound than the Hugo 2 or Schiit Bifrost Multibit / Schiit Lyr 2 for the Grado PS1000e.

BLIND TESTS

In these tests, I arranged the connections into the various systems while my wife Ruthie (of "ruthieandjohn," my screen name) listened to the pieces shown. She is consistently able to discern differences in headphones and amps better than I can. One of these was performed with the low-cost Grado SR125e ($150), the other with the high-end HiFiMAN HE1000.


Fig 9: Blind test comparison of Hugo 2 to either Hugo 1 and iPod Touch (top row) or Lotoo PAW Gold and Schiit Bimby/Lyr 2 (lower row) shows Hugo 2 excelling in sound quality.

In the test against the Hugo 1, the Hugo 2 was said to be "clearer and cleaner." Instruments seemed better separated and did not blend (thought the blending of the Hugo 1 sound was regarded as very pleasant. Even modestly-priced headphones can benefit from the Hugo 2 (of course, they ARE Grados, so what would one expect?)

In the tests vs. the Lotoo and the Schiit components, the Hugo 2 was regarded as placing the listener more into the middle of the music, which surrounded the listener more.

VARIETY TESTS

Some folks on the Hugo 2 Tour thread have expressed interest in the Audeze Sine 20 IEM. While I don't have that, I do have the highly excellent AKG K3003i IEMs, one of the best universal fit IEMs, so I performed comparisons with it between the top performing Lotoo PAW Gold and the Hugo 2. In similar vein, I compared my three top headphones, the HiFiMAN HE1000, the Sennheiser HD800, and the Grado PS1000e, using several examples of music types and playback resolutions, from the 44.1 K, 16 bit samples of lossless CD to the 192 K 24-bit samples of high resolution. Here are the results.

Fig 10: For a top-end IEM, the Hugo and the Lotoo PAW Gold work equally well. For close-mic'ed solo piano music ("Goldberg Variations"), the solo piano was just a bit more realistic with the Lotoo. The Hugo 2 outperformed the Lotoo for the Sennheiser and Grado headphones and was equal for the HiFiMAN.

SUMMARY

The Hugo 2 is a winner! Despite having close to 50 pairs of headphones, about 8 portable DACs (including the Hugo), perhaps 5 portable amps, 6 desk-sized amps, one desk-top DAC, and other associated gear, I hope to be able to purchase one in the not-too-distant future. In addition to providing the best sound I have heard from any DAC, portable or desktop, the Hugo 2 has added a supreme amount of convenience with its physical upgrades. I would be most interested in how it compares to the Schiit Yggdrasil as perhaps one of the best DACs ever.

As proud owner of the largest collection of Grados in private captivity (26 pairs), I inquired of Grado as to what portable amp they found best.  They indicated that the Lotoo PAW Gold and PAW 5000 were better than the traditional DAP/AMP/Headphone combination, so I got this PAW 5000.
 
WOW!  I could IMMEDIATELY hear an improvement on my Grado RS1e and then the HF-2 and several other Grados over the iPhone 5, iPod Touch 6, FiiO X3, and FiiO X5ii that I had been using.
 
 As the documentation was sparse, the operation of two keys labeled ATE/PQME and DAMP were not explained.  A bit of research indicated that ATE/PQME provides a five-band parametric equalizer with several presets (including two adapting it for the AKG K701 and the Beyerdynamic 990)  and six user-specified settings.  A bit more investigation found a setting from Lotoo that further improves sound, and another from a head-fi user that makes some more gentle improvements.  
 
This is the first time that I have ever heard a significant improvement through the use of an equalizer.  I am a convert.
 
Even without the EQ, this is the best DAP that I have heard.
 
I have enjoyed this so much that I am now vigorously trying to obtain its big (and MUCH more expensive) brother, the Lotoo PAW Gold.  It is very hard to find right now.
 
PROS:
 
The sound is significantly better than other players in this price range.  I immediately perceived an increase in soundstage and greater spatial separation of instruments.  
 
The equalizer actually works... perhaps they use a higher-order parametric filter bank (flatter peak, faster fall-off) than the typical Gaussian-shaped second order type.
 
The player has sufficient power to power even inefficient headphones well... 500 mW/channel into 32  ohms.
 
The player is light (110 grams) and small (roughly 3-1/2" x 2" x 5/8").
 
It has a USB3 port, which means that it can download music faster into its up-to- 2TB (when available) micro memory card.
 
The Lotoo PAW 5000 charges through this USB port, which can also use a standard USB2 cable into part of its opening.
 
CONS:
 
The PAW 5000 only plays sample rates up to 96 Ksamples/sec.  It will accept files at higher rates and play them, but it plays them at 96 Ksamples/sec.  
 
Putting album artwork in is a bit dodgy...  cover art must be a .jpeg file of less than 150 kB and must be in the same directory as the songs.  Higher level artists directories (if you use a structure of a folder for an artist with subfolders for each album) will not show any artwork unless you put a picture in it along with the album folders (perhaps of the artist's face?)
 
The player is a bit hard to turn off.  It extinguishes its display to conserve battery life (though you can either leave it on or increase the time via system settings), and you must turn the display back on by pressing the gold button on the front before you can then stop play.  If you quickly need to turn it off, it is simpler to just unplug the headphone, which also stops play.
 
OVERALL
 
I love this player.  Recommended by Grado for its headphones, it has caused me to seek to shell out over 10x as much for the Gold version (even more highly recommended, and found by some to be preferred to such better-known top-end players as the AK240 and -380).  It plays significantly better than my best other player, the FiiO X5ii.  It has convereted me to a user of parametric equalization, to the point that I am developing some software tools to display and optimize parametric equalizer settings and compare them to headphone frequency plots.  I highly recommend this player.

INTRODUCTION
 
The V-MODA VAMP VERZA DAC and amplifier is only about 1/4 inch in each dimension larger than an iPhone 5, yet provides a novel and useful method to attach to the iPhone as a single unit and provides excellent sound in a shirt-pocket-sized stack with the iPhone in the V-MODA Metallo case, particularly with the V-MODA M100 headphone for which it has been tuned.  
 

The picture shows the VERZA with its silver volume control knob underneath a matching Metallo case holding an iPhone 5.  The Metallo case slides onto the VERZA along a track and a small lightening-to-USB connector connects the two (at the far end of the unit).  Testing was done with a V-MODA M-100 headphone, as shown.
 
QUALITY
 
The unit feels solid and is sold with an Apple Lightening-to-USB cable of minimal length to connect the two units. It would be better if the cable were a right-angle cable at each end, so the short length of wire is not increasing the length of the stack.  It would also be great if the cable was white for those VERZAs that are white (my cable is black).  The package also includes the Apple 30 pin - to - USB connector.
 
As described below, the sound is excellent.  
 
However, the unit is not always able to seize control of the Apple Lightening connection when plugged in, specifically if the VERZA has discharged its power (such as being left on all night) and then recharged.  This is a problem that has been noticed by several others on the head-fi.org thread on the VERZA and Metallo case, for years, though in my case, it only happens (but almost always happens) upon full discharge of the VERZA battery.  Fixing it (i.e., causing the VERZA to actually connect with the iPhone) requires random cycling of power, unplugging and plugging the Lightening connector, switching through the various modes (VAMP, VAMP/Power, Synch on one switch; iAMP, USB-DAC on the other).  Once it connects, it stays connected until the next time that one discharges the VERZA battery, but it is a random process of unpredictable duration to cycle through the various combinations of actions to cause it to reconnect.  When it has not reconnected, the sound of the iPhone music comes out of the iPhone speaker rather than the headphones hooked to the VERZA.  If V-MODA is not able to fix this problem in the design, it would still be helpful if V-MODA would publish a sequence of steps (on/off, switch cycling, plug/unplugging) that would reliably bring the connection between iPhone and VERZA back to life upon VERZA discharge/recharge. Several calls to V-MODA were not able to elicit any solution to this problem.
 
The Metallo case that holds the iPhone and slides onto the VERZA has its own set of challenges.  I am on my third case at this point of four months of ownership.  The metal of the track on the Metallo case is either milled too loose or tends to wear away or bend such that the track no longer holds onto its mating track on the top of the VERZA case, and your iPhone can fall off.  Furthermore, it would be useful if there were a firm locking "click" when the iPhone in the Metallo case has slid fully onto the VERZA.  There is not, and the Metallo case slides free, restrained only by the Lightening-to_USB plug. That problem, too, has been common to all three of my Metallo cases.  V-MODA has been very helpful in sending me a new case prior to my sending them the old, so i am not without a case during postal transit times.
 
 
SOUND
 
Of course, the VERZA sounds fabulous, particularly with the V-MODA M-100 headphones that I used to test it.  
 
To quantify "fabulous," I used a regimen of 10 three-way comparisons, in which I rank the ability of three different systems as "best," "next best," and "third best" in reproducing ten different aspects of headphone listening (e.g., transparency, soundstage, subbass, as shown in the table below).  I described this method, including the specific pieces and several-second segments of these pieces, here. 
 
The three chains I chose to compare were the VERZA with M-100 driven by my iPhone 5S, the M-100 driven directly by my iPhone 5S (no VERZA), and the Sony PHA-1 DAC/ amp driving the M-100 from the iPhone.  I chose the Sony PHA-1 because it is similar in price to the VERZA and because like the VERZA, the PHA-1 has a 10 ohm output impedance.  A 10 ohm impedance is rather high for such headphones as the 32 ohm input impedance of the M-100 or the Grado headphone line, as a rule of thumb is that the output impedance of the amp should be less than 1/8 of the input impedance of the headphones, to keep the bass tight.  In this case, it is 1/3.2, or about 1/3, of the headphone input impedance.
 
This table shows the ranking of the three chains for each of the 10 acoustic tests.  Each test is a row, and a brief explanation sits at the right of each row.  Each of the three chains is ranked as best (score of 3, box color of blue), second best (2, blue), or third best (1, yellow) on each acoustic test.  Ties are allowed (indeed, encouraged, as I must hear a difference that I think is sufficient to be reliably reproduced before ranking one above another).  Ties for first place are purple (blue+ red) and scored 2.5; ties for second place are orange (red + yellow) and scored 1.5.
 

 
One may compute a total score, indicative of how many first places vs. third places each chain had.  That shows that the VERZA with M-100 sounded just a bit better than PHA-1 with M-100 (differences of three are significant - this is only a difference of one).  Both amps sounded significantly better than the M100 without an amp, i.e., driven directly by the iPhone.
 
CONCLUSION
 
I really like my VERZA amp, so much so that after I got it, I purchased, for the second time, a pair of V-MODA M-100 headphones, this time in matching colors (I had a pair earlier that I had sold).  I find the small size of the VERZA and its simple, unique way of sliding the VERZA amp onto the iPhone 5 V-MODA Metallo case as a wonderfully compact, attractive way to always have a top-quality portable DAC/amp with my iPhone.
 
If only the VERZA would reliably capture the Lightening connection to the iPhone every time after power discharge / recharge of the battery, and the Metallo case would stay tight and click at the end of its transit onto the VERZA amp track and not fall off, this would be a perfect product for me.

Background
 
In about 1990, when Joseph Grado was designing his HMP-1 Holographic Scalera Scanner (perfectly-matched pair of microphones for recording), he needed some detailed, neutral headphones to diagnose the HMP-1 performance, so he developed the Joseph Grado Signature Products HP-1000 headphone (three versions- HP-1, HP-2, and HP-3).  His headphones came with instructions for building a resistive divider to properly drive them from speaker terminals.
 
But he then saw the need for a true headphone amplifier.  He engaged Sidney Stockton Smith, designer of several renown Marantz amplifiers, to design an amp, the HPA-1, that was perfect for his HP1000 and portable for use wherever needed in recording studios.  Then he and Sam Cadawas, former quality engineer for Marantz, built about 150 of these at Mr. Grado's kitchen table, selling them for $795, plus a hefty wall-wart power supply, the P/S-1, for another $120.  Even at that price, they lost money and soon stopped making them.
 
More recently, elements of HPA-1 are captured in the current RA1 amplifier now sold by Grado Labs in a wooden case.  Here are both amps, along with the headphones for which each was originallly designed.
 


Grado Labs RA1 portable amp and RS1 headphones (left) and Joseph Grado Signature Products HPA-1 portable amp and HP1000 headphones (right).
 
Construction
 
Construction inside the HPA-1 consists of a hand-soldered prototype board of circuitry, covered on the top (component) side by a black metal shield which is glued into place.  All wiring is point-to-point, and two black stubs of wire shown here function in a mysterious way (capacitors?).
 


Hand-built circuit board of  HPA-1, covered by black metal shield.  Four 9V batteries (two in use and two spare) are shown at the right.
 
Large capacitors (330 uF) and additional metal shielding sit just behind the front panel, and the potentiometer is the RK-40 of ALPS, the best potentiometer of the time.
 

Top capacitor (330 uF) filters +V and -V to ground; metal shield hangs over front panel components.
 
The wire used in the HPA-1 is most unusual.  It consists of an outer colored insulating tube, then a mesh of copper wire braided around a central core of clear polyethylene.
 

 
 
Performance Tests
 
What can I say?  The HPA-1 sounds fabulous with any of the Grado headphones.  I have compared it with two less-expensive amps said to share the same circuitry, though realized out of lesser components.  The HPA-1 "children" I used for comparison are the Grado Labs RA1, packaged in a carved wooden box, and the JDS Labs C-MOY BB 2.03, sold in an Altoids mint tin.
 
I used four songs, all encoded in Apple Lossless Format at CD quality (I actually bought the CDs and ripped them... no internet download involved) and played by my Apple iPod Touch 5th Gen.  Because each of the 10 acoustic tests used a limited segment of music (2 - 10 sec), an infinite loop was used to repeat the appropriate segment of each song while headphones were switched in and out.
 

• "You're Going To Miss Me When I'm Gone," by Band of Heathens, from their album One Foot In The Ether (used for fidelity of drum sound, positional resolution of two vocalists, and ability to discern pitch of string bass passages);
• "Spanish Harlem," by Rebecca Pidgeon, on The Ultimate Demonstration Disc of Chesky records (used to assess female vocals, transparency, the attack of finger on bass string, and high resolution discrimination of differences in shaker shakes);
• "Symphony No. 3 in C Minor Op. 78 (Organ Symphony) - IV" by Camille Saint Saens played by Lorin Maazel and the Pittsburgh Symph  
  ony Orchestra (used to assess the "ripping" sound of well-rendered lower brass and organ reed pipes, and the ability to hear a very small entrance amidst a bombastic chord of orchestra and organ at full tilt);
• "Throwback" by B.o.B. on Underground Luxury (used to assess ability of a bass tone, specifically lowest C on piano at about 32 Hz, to pick me up by the throat and shake me!)

 
The 10 tests were as follows:
 

• Transparency:  What is between me and the music?  A felt cloth?  A "Sennheiser veil?" A frosted window?  Dirty window?  Clear Saran wrap?  or nothing?  At its best, makes me forget I am listening on headphones and am in room with musicians. [I use the 12-second segment 0:00 - 0:12 of "You're Going To Miss Me," which is kick drum, guitar, piano, and cymbal for this test]
• Width of sound stage:  How far to the left and to the right, (yes, AND up and down in best cases) does it seem the musical sources are arranged? [I use the same 0:00 - 0:12 segment of "You're Going To Miss Me,"  which starts with kick drum center, guitar #1 right of center piano far right, guitar #2 far left, to see 1) to what extent am I among rather than in front of the musicians, and 2) how wide an angle do those positional extremes of instruments form?]
• Positional resolution:  Can I distinguish a difference in position of two singers in Song 1? [I use 0:30 to 0:38 of "You're Going To Miss Me," where one vocalist ends a verse and a second vocalist, standing next to him, takes up the next.]
• Bass visceral:  Does the bass in third verse of Song 4 actually shake me? Or do I just hear it?  [This test uses 0:31 through 0:33 of "Throwback, " where the bass drops to the lowest C on the piano.]
• Drum "twang":  At start of Song 1, do the bass and tom tom drumhead have a tone and a pitch, rather than just a thump? ["You're Going to Miss Me" 0:00 - 0:12]
• Bass pitch perception:  For the complicated bass runs in Song 1, do I hear a pitch with sufficient accuracy to sing or transcribe the part? ["You're Going to Miss Me,"  1:02 - 1:23 to see if I can hear the pitch of not only the bass glides and accented notes, but also the grace notes]
• Bass finger pluck:  Do I hear the actual impact of fingers on the bass string just before hearing its sound on Song 2? ["Spanish Harlem," 0:00 - 0:04, listening most carefully to the repeated 3-note pattern to see if I not only hear an initial attack but some structure immediately following, before the finger leaves the string and the sound just rings)
• Shaker variation:  In Song 2, verse 3, do the various shaker shakes sound a bit different from each other, as they should? ["Spanish Harlem," 1:40 - 1:47:  there are clearly loud and soft shakes, but how many more volume levels of shakes can I distinguish, and can I hear structure within each shake as the seeds hit the shaker wall?]
• "Ripping" of organ / brass:  In Song 3, is there the sensation of hearing each vibration of the French horn and low organ reed tones (sort of the tonal counterpart to hearing a "pitch" from a drumhead in Test 5); ["Organ Symphony," initial chord from 0:00 - 0:04 and French horn passage 0:06 - 0:12]
• Discern added chord:  About 1:38 into Song 3, after the full orchestra and organ hold a chord at the top of a passage, can I hear a small number of orchestra instruments join in, as sort of an echo, in the second measure of that chord? ["Organ Symphony," in the passage starting at 1:08, how well can I hear the small additional chord added at 1:16 on top of the full strength organ/orchestra chord in progress?  Clearly enough to have noticed it if I weren't already listening for it?]

 
These tests generally emphasize what I find most pleasing in a headphone, namely high-frequency-related features including transparency, upper harmonics of sounds from drum-head, brass, organ pipe, and string bass, and high-resolution effects such as fine detail of each shaker sound and the finger on the bass string.
 
Performance Results
 
Here is how the HPA-1 compared to the RA1 and the CMOY BB 2.03.  For each of the 10 acoustic features mentioned above, I ranked each amp, as heard through the Grado Labs RS2i headphones.  I awarded the best performer of the three amps a first prize (blue, 3 points) for each feature, with second place (red, 2 points) and third place (yellow, 1 point) for the other amps as appropriate.  I allowed for ties (2.5 points, purple, for tie for first; 1.5 points, orange, for ties for second place).
 

Comparison of the Joseph Grado HPA-1 to the Grado Labs RA1 and JDS CMOY BB 2.03 shows HPA-1 with overall top score, excelling on bass and soundstage width (all used the Grado RS2i headphone).
 
 
Score differences of less than three are not likely significant.  Best performance was given by the Joseph Grado Signature Products HPA-1 (also the most expensive, at $1,000, though out of production). The Grado Labs RA1 scored second, with a bit less soundstage and less subbass.  The CMOY was third, but was a very good amp.  However, the CMOY had one significant problem -- for the subbass test (Song #4 above), the subbass tone was very distorted.  This held at any volume level, and the batteries were fresh.  The bass boost was turned off on the amp.  
 
But aside from this subbass problem with the CMOY (which is a rare occurence), the differences were small enough that if I were just presented with one amp to hear, I would not likely be able to tell which it was.
 
I also explored the ability of the HPA-1 to drive another headphone, the HiFiMAN HE1000 that has just been released.  The HE1000 is a planar magnetic headphone retailing for $2,999, stated to have an input impedance of 35 ohms +/- 5 ohms, not too different than the 32 ohms of the Grados.  However, the HE1000is of less efficiency than the Grados, advertised at 90 dB per mW but measured by some as even lower (the Grados are generally 97 db - 100 dB / mW).  I performed two three-way comparisons - to the CEntrance HiFi M8 portable DAC/amp and Sennheiser HDVD 800 DAC/amp (first table), the HiFiMAN EF6 and EF5 (second table),and to the Schiit Lyr 2 and HiFiMAN EF-6 amps (third table).
 

 
Comparison of HPA-1 to CEntrance HiFiM8 and Sennheiser HDVD 800 DAC/amps driving the HiFiMAN HE1000 headphone shows that the HPA-1 ties the HDVD 800.
 
Surprisingly, the HiFi M8 performed overall more poorly than the other two amps.  It was never first place for any of the 10 acoustic characteristics.  The HDVD 800 won on transparency, while the HPA1 provided the largest sound stage.  In fact, the larger sound stage of the HPA1 was apparent within the first few seconds of listening.  All of the amps sounded excellent with the HE1000.
 
 

Comparison  of two HiFiMAN amps, the EF5 and EF6, to the Joseph Grado HPA1 place the HPA1 performance between that of the EF5 and E6.
 
Surprisingly (at least to me), the Grado amp performed significantly better than the EF5 amp.  The EF6 amp performed best of all.  Both the EF5 and the Grado amp required volume turned up to 90% -100% of full, while the EF6 kept the volume around 50%.  I conclude from this comparison that a ~$500 amp (such as the Schiit Lyr 2, a hybrid tube/op-amp amp that I had been considering), at least to the extent of its similarity to the EF5 hybrid amp, would not perform as well as the Joseph Grado HPA1 that I already have (though the Lyr2 puts 6W, not 1-2 W, into 32 ohms, so there is a difference with the EF5).
 

 
When compared to the Schiit Lyr 2 and the HiFiMAN EF-6 amp, the HPA-1 performs less well in driving the HE1000.  Both the Lyr 2 and the EF-6 can put 5 - 6 watts of power into 35 ohms, far more than the HPA-1.
 
As shown above, the HE6 outshone the Lyr 2 (and the Grado HPA1) for driving the HE1000, having better soundstage, more transparency, and better bass impact.  The volume control on both the Lyr 2 and the HPA1 was at about 90% of full; the volume knob on the EF-6 was at about 50%.  However, differences in sound between first and second place, and second and third place, were very small for these amps -- even the HPA1 sounded very, very good with the HE1000.
 
Conclusion
 
What can I say?  The HPA-1 sounds fabulous with any of the Grado headphones, and it does a great job of driving a lower-efficiency headphone, the HiFiMAN HE1000.  Additionally, there is the mental vision of the late Joseph Grado, perhaps wearing his huarachi suspenders, hunched over his kitchen table, soldering iron in hand, building My amp, for ME!
 

This combined DAC and amp, based on the renown Wolfson DAC chip, is 2" x 2" x 3/4" deep, smaller than a roll of Scotch tape.  It includes a convenient skin-tight case that snaps it to your belt. 
 
The A 200 p has a large disc volume control (5 revolutions from softest to loudest), best equipped with one of the rubber stick-on nubs included to give your finger purchase to turn the smooth metal surface.  It also has touch controls that stop, skip, or repeat selections played on an iPod.
 
Most importantly, it DIRECTLY reads the Lightening 8-pin connector used by current-generation iPods and iPhones, receiving the digital bits.  Unfortunately, this is ALL it reads... no USB or line in for other signal types.
 
I had become addicted to the power of a portable DAC/amp combination that read iPod signals directly by my earlier purchase of the Sony PHA-1, also using that Wolfson DAC, having a greater variety of inputs, and nearly 40x greater volume, at 4" x 2.5" x 1".  When I purchased the Beyerdynamic T 5 p closed headphones, I decided this companion Beyer component would be just the thing.
 
I have been delighted.  Its sound is wonderful, providing a larger soundstage with greater positional resolution than without this device (as was the case for the Sony PHA-1).  But this also adds the iPod transport controls in a handy spot, as many top-end headphones, including the Beyer T 5 p and the Grado line, do not include an in-line remote that is so handy on the move.
 
Output impedance is 1.1 ohms, great for the 32 ohm input impedance of the Beyer T 5 p (and Grado) headphones.  This is in contrast to the Sony PHA-1, which has a 10 ohm output impedance that is a bit higher than the 8X rule of thumb would suggest for 32 ohm headphones (headphone input more than 8 x amp output impedance).
 
Another niggling nuisance is that the digital input plug where the Lightening connector goes looks like a mini USB, but really is a Beyerdynamic special.  They include both a cord with a lightening connector on its other end for your iPod, and another with a USB on the other end for charging, but it seems unusual that they did not just choose to use the standard USB mini plug.  However, the cord intended to reach to the iPod is only 4-1/2" long, a bit short if you hang the A 200 p on your belt and put your iPod into your pants pocket, as I do.  You cannot use a third-party USB-to-Lightening cable to replace it, as its end is the proprietary Beyer connector.
 
Overall, great DAC/amp for portable use with no compromise in sound and excellent transport remote controls.

Background
 
I had by happenstance acquired a pair of these in the mid-1970s, well before my interest in quality headphones, and then set them aside in a box of "junk" electronics, where they have remained for nearly 40 years, since they didn't fit into the headphone jack of any of my systems.  When I saw a post recently that sung the praises of these, I had to dust them off, run appropriate wires for my home system, and plug them in.
 
WOW!
 
I could not put them down and stayed up until 3:00 am trying various tracks through these headphones.  I had purchased a pair of Grado PS500s within the past few weeks as my best pair of headphones so far, but my initial listen made me think that these were better (more detail on that statement below!).
 
Sound Quality
 
In short, these headphones are "bright," but not "in-your-face" bright.  The attack of a drum stick on a snare drum comes across just as if it were live, suggesting great transient response.  There is no "veil" between you and the instruments... regardless of pitch or timbre.  I would imagine one would call these headphones "fast."
 
Lower bass is light, but not unpleasantly so.  In fact, I can discern the pitch of each note in a complicated plucked bass sequence in the face of other instruments, as the clarity and lack of fuzzy boominess in the bass more than compensates for its lesser relative volume.
 
I have been comparing headphones, in sets of three, in a rather systematic manner, so I imposed those tests on these to provide some comparisons.  I compared these Stax SR-5 headphones with SRD-6 drivers to both my best headphones (Grado PS500) and my best IEMs (Klipsch S4i), with the idea being that IEMs might come closer to the "fast" response I was hearing from the Stax than the Grado.
 
To test various aspects of sound quality, I used an iPod Touch 5th Gen source patched into my Technics full-sized stereo system.  The SRD-6 was driven by the "remote" speaker output and in turn drove the SR-5 headphones.  I devised a set of 10 comparative tests (4 that are of an overall quality nature that do not depend a lot on the music being played; 6 that compare the clarity of specific acoustic "events" in certain music). I describe the test methods more fully here  http://www.head-fi.org/t/704826/how-do-you-audition-compare-headphones#post_10340917 .
 
Rather than trying to give an absolute score to each headphone for each criterion, I simply rank ordered them, based on back-and-forth pairwise listening for each test and each pair of the three headphones (took between and hour and an hour and a half).
 
The overall, or "macro tests," were briefly (more detail in post cited above):
 

1. Transparency;
2. Size, both horizontal and vertical, of sound stage;
3. Resolution of position of two persons singing near each other;
4. Volume of headphone with iPod turned up all the way.

 
The event-based tests were:
 

1. "Twang" of drumhead at entrance to Song 1;
2. Preservation of features allowing me to determine pitch of bass notes in Song1 Verse 3)
3. Finger pluck at start of bass notes at start of Song 2;
4. Clarity of shaker, preserving differences of each shake, in Song 2 Verse 3;
5. "Ripping" sound characteristic of horns and medium low reed organ pipes at start of Song 3;
6. Ability to hear additional echoing chord stacked upon a huge bombast of sustained full orchestra and organ four beats later, in about third "verse" of Song 3.

 
Here is the result of my comparison.  A 3 indicates that headphone was the best of the three in that test and contributes 3 points to an eventual headphone score totaled at the end... a 1 means it was the worst.
 
 
Since these scores reflect rank order position rather than absolute ability, total scores can be deceptive.  For example, the width of sound stage of both the Grado and the Stax were very similar, with the Grado doing just a bit better, while the Klipsch soundstage was so reduced as to render the whole IEM a bit disappointing... yet that only amounts a difference of one or two points on one of 10 criteria.  So even though the Grado and the Klipsch score equally, the Grado is far preferable.
 
More preferable still is the Stax, by a significant amount.  None of these tests really capture the relative lightness of its bass.  Published plots of frequency response show a flat contour down to about 60 Hz, from which point the response drops off by about 8 dB as one moves down to 20 Hz (marketing parlance would still call this "flat +/-4 dB.")  However, non-sound attributes limit its attractiveness:
 
Quality Excluding Sound:
 
The Stax requires both a wall plug for power and a speaker output for signal.  Hence, it requires that the listener come to it, rather than allowing the listener to take it along, as wall plugs require walls and speakers usually require large floor- or rack-mounted stereo systems.  The SRD-6 transformer box provides a switch and set of speaker outputs, so one can use it to switch between sending the music to full size speakers or to the Stax ear speakers.
 
The headphone is very comfortable.  Its over-ear design make it more acceptable for long listening sessions than the Grado PS500, which is on ear and can become fatiguing as it presses your ears against your head.
 
I perceive no degradation to the Stax from sitting for years and Years and YEARS in a junk box of electronics with tangled cables and sharp-cornered small aluminum electronics boxes (headphone switches and the like).  Both side are balanced (some writers caution against channel imbalance for Stax). 
 
I believe that the Stax SR-5 ear speaker and its SRD-6 transformer constitute one of the least expensive ways of leapfrogging into audiophile quality on a budget.  The system is often offered on eBay for a few hundred dollars.

Sorry... headphone display stand shown in this Grado Labs photo was somehow missing from my PS500 headphone box!
 
Since my first revelation into "good" headphones was via my Sennheiser HD 598s, which introduced me to great soundstage, imaging, and comfort, I was looking for something that moved further in the same direction for my upgrade, the PS500s.  Detailed listening comparisons in the Overture Audio store where I bought these examined the HiFiMan HE 500, these Grado PS500s, and my Sennheiser HD 598s.
 
I used four "macro" tests that used all of the music, plus six "event-based" tests that compared the rendering of various small pieces of music, compared by repeating back and forth between two headphones.  I simply ranked the ability of each headphone first (3 points), second (2 points), or third (1 point) for each test.  More detail, including identity of the three songs, in this post: http://www.head-fi.org/t/704826/how-do-you-audition-compare-headphones#post_10254063 .
 
The macro tests were:
 

1. Transparency;
2. Size, both horizontal and vertical, of sound stage;
3. Resolution of position of two persons singing near each other;
4. Volume of headphone with iPod turned up all the way.

 
The event-based tests were:
 

1. "Twang" of drumhead at entrance to Song 1;
2. Preservation of features allowing me to determine pitch of bass notes in Song1 Verse 3)
3. Finger pluck at start of bass notes at start of Song 2;
4. Clarity of shaker, preserving differences of each shake, in Song 2 Verse 3;
5. "Ripping" sound characteristic of horns and medium low reed organ pipes at start of Song 3;
6. Ability to hear additional echoing chord stacked upon a huge bombast of sustained full orchestra and organ four beats later, in about third "verse" of Song 3.

 
Here is the result of my comparison.  A 3 indicates that headphone was the best of the three in that test and contributes 3 points to an eventual headphone score totaled at the end... a 1 means it was the worst.
 
 
So for what  was looking for, which is what the test criteria try to measure, the Grado at 24 points was significantly ahead of the HiFiMan, at 19 points, and my reference Sennheiser, at 17 points.
 
The Grado PS500 clearly spends your money on the headphones, not the box.  While my Sennheiser, Beats, and NAD headphones come in cabinets ("box" is a desecration to what they are shipped in!) that could almost be placed on your living room table, the PS500 comes in a box that from the outside looks like a Krispy Kreme doughnut box... thin cardboard, three-color printing, flat -- and inside are foam cutouts to hold the headphones.  Cord is not removable.  The cord is heavy... in fact, Grado makes a point of the type of very-low-resistance conductor that is used. It is perhaps six feet long and terminated in a 1/4" jack.  Grado sells a 1/4" to 1/8" adapter, about 9" of the same heavy cord, that one can add to get to the iPod jack size.  Cord and adapter together are double the weight of the iPod Touch 5th Generation and I fear place a strong sideways pull on the iPod headphone jack if the weight is not borne by something else.
 
The PS500 has a 32 ohm input impedance, which is low enough that the iPod output can drive it easily.  Efforts to add an amp (in my case the FiiO E12 "Mont Blanc") are superfluous... the amp does not improve the sound at all, at least to my ears (and the sound is already great).
 
These headphones are open back, on ear cushions.  I love the open back, but the on ear cushions can tire your ears out from the pressure.  Grado sells, and I bought, the larger over-ear "G-cushion" that Grado uses on their highest-end headphones, the PS1000. Various reviews claim that these improve the sound as well as the comfort, but I heard no difference in the sound during casual listening (haven't listened really critically yet).
 
If Beats can be said to exude a hip(hop), ultramodern look, these Grado PS500s can be said to be just the opposite - utilitarian and retro. I am convinced that the headphones of Radar O'Relly on M.A.S.H. looked exactly like these!  Though hidden by the ear cushions, the design includes wood as well as the more prevalent metal, chosen and placed to reduce resonance and improve sound.
 
The Grados are one of the not-too-many top-audio-quality headphones that have a low enough impedance to be directly driven by iPhones and iPods.  I really do wish that Grado would offer an iOption of a cord that is 1/2 the length and 1/2 the thickness, terminated by a 1/8" plug, to complete the compatibility with the iPod.  I believe they would significantly increase their market share if they did.  They did indicate that third parties offered such cables (don't know who) and that they, Grado, would replace my cable with one if I sent both cable and headphone back to their place in Brooklyn, NY.
 
I paid $600 for mine, plus about $60 for the larger earpads and Grado adapter.  The Grado site (gradolabs.com) cautions that you NOT purchase these from an unauthorized dealer, as that voids the warranty.  They specifically mention eBay, as well as pointing out that some of the sellers represented on amazon.com are not authorized.  They urge you to check with them as to whether a dealer is authorized.
 
In short, I love these headphones.  The day that I got them, I wrote Grado expressing my satisfaction (I felt fortunate to purchase a pair that had been demoed for several months and was therefore burnt in).  I told them that I was unable to take them off and asked whether they could be worn in the shower.  No!  I've sought to compare them to a few others that may be known to the reader, and purchasing these (unfortunately) only stoked my thirst for even-more-expensive headphones (looking at the Sennheiser HD 800 now, but love these).

Beats claims, "Music as the artist intended," and "You're not hearing all the music.." This leads me to expect that I will make new discoveries in familiar music when I listen through Beats headphones.
 
I indeed have heard new things in old music with Beats, listening to songs I have listened to DOZENS of times on my other headphones (Sennheiser HD 598, Parrot Zik, Apple In-Ear (their best), Klipsch s4i, and others). In about 25% of familiar songs I hear something new with Beats, spanning genres of classical, hip hop, electronic, and others.
 
I take this to mean that the headphone sound quality is at least comparable or perhaps better than these other headphones. It is also much better than that of the original Beats Studio. The headphones are my most comfortable and are awesome at noise cancellation. While being large enough to be "over ear," they are small enough to be light and comfortable and do not fall off your head when doing such repetitive motions as scrubbing or vacuuming.
 
One quirk is that the headphones are turned on by plugging in their cord... an unfortunate result is that if you just take the headphones off, they remain on, unless you pull out the cord (or turn off the power switch). Leaving the cord in without turning them off depletes the battery and requires recharge.
 
These headphones have turned me into an aficionado of both hip hop music and Beats products. I have just purchased both the wireless version of these headphones as well as the Beats Pro headphones, taking advantage of the "Buy 2 Beats for 10% off" special ending Feb. 8, 2014. I have also purchased the Beats premium audio in my new FIAT Abarth (fabulous!) and am subscribed to the new Beats Music streaming service.
 
But I recognize that they are not the high-accuracy headphones that provide the best listening experience, with transparency, good sound stage, and precise spectrum.  Hence, I have also purchased the similarly-priced NAD VISO HP50. I'm looking for diversity of listening experience as I augment my headphone collection to 20.
 
Value:  3/5
Audio Quality:  4/5
Design: 4/5
Comfort: 5/5