Head pie has already reviewed the DX200 and within there, and in  the Amp 2 review we covered Amp1.

DX200 review:   https://headpie.blogspot.jp/2017/03/ibasso-dx200-review-expatinjapan.html?m=1

Amp 3 is soon to be reviewed, and later amp 5 and 4. Eventually there will be a concise summary of all five amps (more, If iBasso create more).

*This is intended more as a one stop shop for general information on the amps and will be slowly added to.



Amp 1





Amp 2










Amp 3





“The balanced High voltage/high amperage AMP3 for the DX200 now available!
Average Play Time: 7.5 hours.
The play time varies with different sample rate/bit rates, and headphone/IEM loads.

Features:
1. +/-8V voltage swing, equal to 32V voltage swing when compared to single ended. This significantly improves the dynamics and headroom.

2. Patented balanced amplification circuit, that retains all the benefits of a balanced design, such as higher output voltage and lower crosstalk. At the same time, our Patented design has even harmonics that keeps the sound full and musical. *

3. Topology utilizing voltage feedback and current feedback, utilizing the benefits of both types of feedback.

4. OPAMP+BUF architecture, optimized for both high voltage demand and high output current demand monitors.

* With the traditional balanced amplification circuit design, there is a positive signal and a negative signal. They together reduce the harmonics, including both of the odd harmonics and even harmonics. On this amplification design, even though sound is more powerful, the sound is often flat and less musical, as even harmonics are reduced. On the iBasso balanced amplification design, we successfully reduce the odd harmonic, while retaining the even harmonics, thus keeping the sound full and as musical as single ended but with the added benefits of a balanced signal.“-
-iBasso /Facebook



Amp 4





“The AMP4 balanced with a 4.4mm TRRRS socket. High voltage and high current with and extremely low output impedance at approximately .3 ohms. Full bodied with a frequency response from 10Hz to 45KHz -0.5dB. “ - iBasso /Facebook








“AMP5 coming your way soon. High current and voltage with excellent frequency extension. A sweet top end with dynamics and headroom for most any headphone or IEM. Single ended in 3.5 TRS” - iBasso /Facebook





HiFiman Edition S review 
by Niyologist

(Originally posted on Head-fi, ported here at the request of Niyologist).

Have you ever wondered what type of headphones you need on the go? Tired of bringing oversized headphones wherever you go? Well if you got a large spending budget for on the go headphones. The HiFiman Edition S Headphones are definitely for you. Not enough information? Well it's about time I got to that.

Introduction: The HiFiman Edition S is an interesting set of headphones from years of engineering from HiFiman. The sole purpose of the Edition S is to provide high quality audio. While maintaining the portable size and with decent durability as well. Is it what it's meant to be? I'll explain that further as I analyze further into detail.

Build Quality/Design: The Edition S is made out of a tough plastic. Even though the headband is made out of hard plastic. It would be better if it were thicker and reinforced by metal. At the headband, it seems that the plastic is quite rigid. There are L and R markers on each side of the bottom headband. Below the headband is the metal housing, with the magnetic grills and the covers to keep it in open back or closed back modes. There's also a removable cable port on the left side of the headphone. The Edition S can be folded and stored in the Silver Headphone carrying case that is provided with the Edition S.




Fit: It's best to have flat hair. Having too much high hair doesn't do the fit any justice. It makes it harder to wear. As for comfort. I can wear this for hours with little to no fatigue because of the soft inner ear pads. It only gets hot in the ear pads when I'm running. I sweat a lot. So this may slightly differ with everyone else.



Isolation: Low to low-end Moderate. Not ideal for very noisy environments. Such as crowded trains and subways and Large social gatherings. This is for closed back mode. Open back mode is a no go. It's low isolation at best.
Source: OPUS #1 (EQ: OFF) (GAIN: MIDDLE) (VOLUME: 124/150)

Specifications:

Style: Open/Closed Back
Frequency Response: 15Hz-22kHz
Sensitivity: 113 dB
Impedance: 18 ohms
Weight: 8.74oz (248g)
Easy to drive?

Yes. With the 18 Ohm impedance and very powerful OPUS #1. It was quite easy. As for my ZTE Axon 7. Kind of. My Axon 7 isn't quite ideal for this analysis anyway.

Sound Characteristics:

We'll start with two separate modes because of their noticeable differences in sound characteristics.

Closed Back Mode:

Bass - There is enough quantity for Pop and Trap music. The interesting observation is that the midbass is limited on closed back mode. Although it's not quite deep. Based on my observations. The deepest Bass I heard from the Edition S on Closed Back Mode was 60 Hz. Although despite the semi deep Bass. The quality is very good. It sounds consistent and feels punchy. With a slight warm tilt. Along with decent slam and quick speed.

Mids - Due to the limited midbass. The lower Mids aren't overshadowed. So the female vocals aren't subdued. They aren't too forward either. I'd say they are inbetween. Moving up to the upper Mids. There's a slight upward tilt. Making it sound brighter with male vocals, most percussion instruments, brass and strings. Surprisingly, it doesn't sound artificial in anyway. The Mids aren't recessed in Closed Back Mode. It's strange how it differs from Open Back Mode.

Treble - I find the treble to be presented as slightly bright. Most of the time, the treble can liven things up. The sharpness of this frequency makes it a bit analytical in bass light soundtracks. Such as MDK's "Shinespark (Evan King Orchestral).The timbre is quite natural in that soundtrack and has no hint of artificial tonality in any way. Generally, the treble is refined and a bit sharp. Not ear pinching sharp.

Soundstage: It's average for an on-ear/over-ear headphones. The soundscape is pretty airy, despite the average soundstage. It's probably due to the somewhat energetic treble. The width is above average and the depth is a bit shallow. That all changed with Open Back Mode.

Accuracy/Imaging - Before I get to Open Back Mode. I should point out that the imaging and accuracy is impressive for a portable headphone like this. The accuracy is quite good. With the oval shaped soundstage. The placement of the instruments and vocals are distinguishable. Which makes the music quite easy to follow. The imaging is quite vivid and three dimensional sound. Which does make the music really pop out at you. That and along with the accuracy makes the Edition S an experience that makes your music come to life.

Open Back Mode:

Bass - This is a bit different. It's warmer. Much warmer. The bass seems to have a softer and slightly slower slam. The texture seems to be a deep layer of smooth clay, being trounced by a bouncing bowling ball. In other words. The bass feels and slams smoothly. Almost silky smooth. This is most likely the boosted mid bass. I find it very good for Trance, Dubstep and even Acid Music. What intrigues me is, how did the mid bass get a boost? I'm still figuring that out. Maybe the panels were acting as a dampening effect?

Mids - This part is a somewhat different than closed back mode. Continuing from the bass, Mids also sound warm. The lower vocals are slightly recessed. This is due to the enhanced midbass. So the female vocals are darker and the clarity seems to reduced a tiny bit. The upper Mids have been darkened a bit too. At this mode. It's perfect, for me at least. The problem is that the deets for the mid-range in general has taken a bit of a back seat. So this means that open back mode is not ideal to hear the distinguished details of the mid-range. Although it does sound more organic and musical than Closed Back mode. So it's more of a trade-off of sorts. Although this is because I prefer the reference type sound of Closed Back.

Treble - This part of the frequency is so smooth and a bit dark. Making the whole frequency average out to mostly neutral. The details aren't distinguished either. They are there. Just not obvious like in Closed Back Mode. Once again. This frequency also sounds organic and isn't recessed like the Mids. Instead it's balanced. One thing I noticed is the air. It pumps more air in open back mode. Probably with the help of the vents. So this prevents the music from sounding too dark and boring.

Soundstage - Due to the combination of the smooth and airy treble. Along with the vents, the soundstage almost doubles in size. It's more like 1.4x bigger. So yeah. The width is well above average. The depth is average and the soundstage is easily above average. The shape of the soundstage becomes more circular shaped. Yet still remains oval shaped. Pretty much like an enlarged oval.

Accuracy/Imaging - This part becomes a bit obscure. It depends on what you are listening to. If you are listening to bassier tracks, the placement of the cues can get a bit smeared. So the soundtrack will sound a bit jumbled. Slightly harder to follow, yet still very listenable. With light bass soundtracks, the sonic cues are still easy to read and it becomes quite a fascinating sound to experience. Like for example. Robert Miles soundtrack "Children (Dream Version) has a decent amount of bass, yet it's not smeared or jumbled up and the sonic cues are easy to follow. Despite all of this. The imaging is very much three dimensional and can be dynamic with soundtracks that demand for it.

Overall Sound Characteristics:

Closed Back - Neutral, Reference-Like and Energetic.

Open Back Mode - Musical, Emotional and Smooth.

Conclusion: I have enjoyed listening to the Edition S for the past 9 months. I'm glad I purchased it after testing it out at the Stereo Exchange last June. This seems to be the headphones for everyone. Although if you have too much hair. The fit may be an issue. Then if you go to noisy areas daily, then you won't find these enjoyable. Or if you want Closed Back Mode with the sound characteristics of Open Back Mode. You may not find this your cup of tea. Otherwise if none of those bother you, then go nuts.


Pros - Interesting and effective Interchangeable Sound Signature, Excellent Imaging, Portability.
Cons - Sub-par isolation, Average Build could be better, Sound is swapped between both modes for a truly ideal consumer sound experience.





 Hugo 2 with Van Nuys cover

Chord Hugo 2 review
- A. 'Reddog' Jones


https://chordelectronics.co.uk/product/hugo-2/

An interview with Chord from December, 2015.


"Hugo 2 is a powerful DAC and headphone amp that builds on the ground-breaking original. Designed for both home and mobile use, Hugo 2 transforms headphones and audio systems’ sound quality with its cutting-edge proprietary DAC technology." - Chord website

Hugo 2 as seen at a Tokyo Headphone show - photo expatinjapan


Hello my name is Andrew Jones and I have been to headphones/ personal audio for about 4 years now. I own all of my equipment and my reviews have not been paid for. I just like to spread my passion for personal audio by giving good, honest reviews.

EQUIPMENT USED
Source : Apple iPad Pro > Tidal or Questyle QP1R >select titles Dac/Amp : Chord Hugo 2
-Amps used for review:
Cavalli Liquid Carbon
Schiit Audio Jotunheim
-Headphones and IEMs used
Audeze LCD i4 and iSine 20, Focal Utopia,  HiFiman HE1000 MrSpeakers Alpha Prime, Ether, Ether C, and Aeon Flow Closed Meze 99 Classic, OPPO PM-3 and Beyerdynamic DT 880 600 OHM.


I have been been looking for a good sounding portable DAC / AMP, to compliment my iPad Pro work station. I have been reading about all sorts of products, and then out of the audiophile wilderness I started to hear fantastic stories about the Chord Hugo 2. And for the last 5 to 6 months I have read scores of impressions and reviews on the Chord Hugo 2.
And then I read a review by a trusted audiophile and friend, in which he said the Hugo 2 was as good if not better as the Schiit Audio Yggdrasil. The mere notion of having a Yggdrasil sitting in the palm of my hand driving my favorite cans as I walked about jamming out; drove me to order a beautiful Black Chord Hugo 2.


The Chord Hugo 2 showed up in a very sturdy box, that kept the H2 safe, during delivery.
Inside the box came the sexy black H2, with a nice assortment of cables and the remote control.
The remote is nice, sturdy, and small. It is ideal for playing with the sound, while on the move, just point at the H2 and do what ever tweak you wish.
Likewise the Hugo 2 is a finely crafted piece of audio equipment, that is definitely bit larger and beefier than my Questyle QP1R or cell phone. But none the less, the H2 and QP1R fit nicely into my leather audio bag.





The Chord Hugo 2 is designed quite well, on one side of the H2, one hooks the micro USB cables to a USB source and to a dedicated charging port.
On the other side of the Hugo 2 one can connect a CD player or DAP using a fiber optic connection. Also one can hook up a Desk Top AMP and just use to the DAC portion of the H2.
And finally one connects the headphones to the H2 using 1/4 or 1/8 jacks.
On the front/ top of the H2, there are 6 lights, that change color to indicate chosen functions. 4 smaller lights indicate Filter, Input, Crossfeed and Power. The larger light indicates Sample rate of the source and the other light indicates volume.
The remote control can be used to alter any function.



Once I had plugged my IPad Pro into the H2, I was just awe struck by the sound of the Hugo 2.
This plucky, little black box of a DAC / AMP sounds spectacular, so natural and so resolute, that I got goosebumps as I heard the sound. The only other DAC to give me goosebumps was the Yggdrasil.
My oh my the H2 definitely sounds as good as the, Yggdrasil, especially depending upon the source.




The H2 has great hitting bass, that does not muddy up the mids. And the mids are ever so natural sounding, with such great detail.
On one track of Frank Zappa’s I could hear the different level of applause, from faint to heavy. And in one of the Dave Brubeck tracks i can hear one of the drummers drop his sticks as Brubeck was on a tangent. Likewise female vocalist like Kate Bush, Grace Jones, and Rebeca Pigeon ( Spanish Harlem) sound breathtaking. Furthermore male vocalist sound so natural sounding. Nat King Cole, Johnny Cash, and Frank Zappa sound so real so life like. I dis enjoy Zappa sing/ play Uncle Remus, through the H2.


The treble seems spot on to my humble ears.. I dislike overly bright tracks like as I dislike the sound of finger nails scratching across the chalk board. I thought the treble was detailed and delivered just the right details for what ever the track called for.
And as amazing as the H2 sounds, one could tweak the filters and crossfeed, to alter the sound to meet ones tastes. I rarely tweaked with the filters but it is sweet knowing I could do so.
Moreover the natural, detailed sound leads to a outstanding, detailed, holographic soundstage.

My He1000 and Focal Utopia’s soundstage sound so three dimensional. one can place the instruments all around the listener. Classical music by Mozart, Beethoven or Wagner sounds spectacular, with such a detailed, holographic soundstage. It is very surreal to be able to listen to such great TOTL sound, while walking about town. The magic is matching the right track to the environment that I am strutting through.



What shocked me most about the Chord Hugo 2, was how powerful it’s AMP section was. I used the H2 to drive every one of my headphones and my cans just sounded great. The best synergy between the Hugo 2 and my many headphones was the Audeze LCD i4.
The bass and mids on the i4, through the H2 just blew me away. The bass was so deep yet controlled. The mids were musical yet ever so natural sounding. Frank Zappa’s Jazz From Hell, through the H2and i4 gave me goosebumps as I sipped a shot of espresso, at the local Brista shop.
Normally I needed to be tethered to a desktop rig to hear such beautifully detailed music, and yet to quote Zappa, I am “Free as the Wind” while using the Hugo 2.
The sunset never seemed so seemingly magical, as I kick back, under a shade tree.


The second best sounding headphone, driven by the H2, was my Focal Utopia. The bass and mids seem to come alive through the Hugo 2. With the Hugo 2, stashed in my leather audio bag, I felt decadent strutting down the sidewalk, with my Focal Utopia strapped to my head, jamming out to some Beethoven. Clock Work Orange kept popping up into my mind lol.


Finally the third best sounding can out of the amazing Hugo 2, was MrSpeakers Ether.
The soundstage, bass, and mids have this light magical quality. I can only imagine how the Ether Flow must sound out of the Hugo 2.
I was greatly surprised by how good the Beyerdynamic Dt 880 600 OHM sounded driven by the Hugo 2. To get the best out of the Dt 880, I had to have it hooked to my Liquid Gold and yet the H2 did a great job.



I hooked up the Hugo 2, too my amps and was convinced that he Hugo 2 could be used as a free standing DAC. I know I can pair either my Liquid Carbon or Jotunheim AMP to the Hugo 2 to have a versatile system, while out on vacation, or for what have you.

I think the Chord Hugo 2 is a greater sounding DAC/ AMP, although a bit pricey, but it does sound as good as the Schiit Audio Yggdrasil, especially when one factors in the fact it can drive so many cans so brilliantly, without the need for a stand alone amp. And I just love the Hugo 2 because I can enjoy such great music while on the go. But I also like using this about device as a desktop device as i type and use my IPad Pro.

The Chord Hugo 2 is a superb sounding TOTL Dac and amp. I have found myself immersed in the music when listening to my tracks, it is versatile and well built.
It is akin to a modern day harp as used by the audiophile muses of old to inspire and captivate the listener.  The sound is so good, that moment of enjoyment seemingly lasts forever...




HUGO 2 – SPECIFICATIONS:

-Chipset: Chord Electronics custom coded Xilinx Artix 7 (XC7A15T) FPGA
-Tap-length: 49,152
-Pulse array: 10 element pulse array design
-Frequency response: 20Hz – 20kHz +/- 0.2dB
-Output stage: Class A
-Output impedance: 0.025Ω
-THD: <0.0001% 1kHz 3v RMS 300Ω
-THD and noise at 3v RMS: 120dB at 1kHz 300ohms ‘A’ wighted (reference 5.3v)
-Noise 2.6 uV ‘A’ weighted: No measurable noise floor modulation
-Signal to noise ratio: 126dB ‘A’ Weighted
-Channel separation: 135dB at 1kHz 300Ω
-Power output @ 1kHz 1% THD: 94mW 300Ω
740mW 32Ω
1050mW 8Ω
-Weight: 450g
-Dimensions: 130mm (L) x 100mm (W) x 21mm (H)
-Boxed Dimensions: 220mm (L) x 122mm (W) x 85mm (H)


-Materials: Clamshell precision machined aluminium casing with polycarbonate  buttons, acrylic signal window, and glass viewing portal. Available in a choice of two colours – natural silver, and satin black
-Battery: 2x Rechargeable custom Enix Energies 3.7v 9.6Wh Li-ion (lithium-ion (2600mAh) batteries*
-Tap length filter: 49,152 – 10 element Pulse Array design
-Play time: In excess of seven (7) hours
-Charging: Nominal four (4) hours via Micro USB at 1.8amps (fast charge) – Nominal eight (8) hours at 1amp (slow charge)
-Connectivity (input): Micro USB (White): 44.1kHz – 768kHz – 16bit – 32bit
-Coax via 3.5mm Jack (Red): 44.1kHz – 768kHz – 16bit – 32bit
-Optical (Green): 44.1kHz – 192kHz – 16bit – 24bit
-Connectivity (input wireless): Bluetooth (Apt X) (Blue): 44.1kHz – 48kHz – 16bit
-Connectivity (output): 1x ¼” jack headphone output
-1x 3.5mm jack headphone output
-1x stereo (L & R) RCA output
-PCM support: 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz, 358.8kHz, 384kHz, 717.6kHz, and 768kHz.
-DSD support: Native playback supported. DSD64 (Single) to DSD512 (Octa-DSD)
-Volume control: Digital, activated in 1dB increments. Last known state saved upon shutdown, with exception of line-level mode
-Line-level mode: Activated via dual press of middle ‘Source’ and ‘Crossfeed’ buttons. Line level = 3v via all outputs. Reset by power cycle
-Power saving mode: Auto-shutdown after ten minutes of input inactivity
-Driver support: Driverless with Mac OS X and Linux, driver required for Windows OS

* Non-user-serviceable batteries are covered by a limited 18-month warranty from initial date of purchase. For full terms and conditions please click here.

 User Configurable Options:
-Filters (Digital):
Incisive neutral (Ultimate reference) (White)
Incisive neutral HF roll-off (High Frequency roll off) (Green)
Warm (‘Smooth’) (Orange)
Warmer HF roll-off (High Frequency roll off) (Red)
-Crossfeed (Digital IIR):
Off – No Crossfeed
Level 1 – Light
Level 2 – Medium
Level 3 – Heavy

 Control options:
Manual
Remote control (included).