Exploring Portable Audio Solutions - Spring 2018

Portable audio has always been on my radar. Back when I first assembled my desktop system my immediate next step was to replicate that level of quality in a portable system. An what I found is that I typically had to spend twice as much to get equivalent quality and often far less power. But that was almost 4 years ago. These days more and more companies are implementing high powered output via balanced amp typologies into their devices! Meaning that getting desktop reference quality audio on the go is becoming easier and easier, without needing the expensive and cumbersome stack-able towers of yesteryear! 

Seeing as how I focused on entry level products in the winter months, for this review I'll be featuring a wider variety of mid-range products both individually and in comparison to my existing gear!As this was my focus for the spring season, I will also be starting my summer adventures by diving into modern Top Of the Line Digital Audio players.

For listening tests on mid range equipment & comparisons I used my AKG K701 single ended and my Modded Audio Technica ES10 balanced. I find that each of these headphones is more neutral than anything, with the K701 being a little brighter up top and the ES 10 being a little darker up top. 

For our first look at more modern Digital Audio Players utilizing truly top of the line topology designs, my track list remains unchanged but I'll be switching between my HD 800, LCD 2 and modded Audio Technica ES10 with a few special guest appearances too! 

I volume match each device/out with pink noise and my SPL Meter and I listened to about 3 tracks with each headphone and device. An you can refresh yourself on my current playlist by clicking here. 

Let's start with a quick refresh on my 2017 product standards consisting of the; 

• LH Labs Geek Out V2+ for my Mid-Range Reference 
• Shanling M2S for my entry level Reference 
• Hifiman HM901 Line Out to my;
• HeadAmp PicoPowerSingle Ended Amp
• iBasso PB2 Balanced Amp 
• As my Top of the Line Portable System

You may also recall that I adopted the Shanling M3s & Aune B1s as a mid range reference as well, while I still feel that system holds it's spot on my list I did not have it in home for this review. Moving forward however I will. 

For this review I'll be starting on Mid-Range devices as this is where I spent the majority of my listening time this Spring, next we will be transitioning to a quick recap of some entry level favorites from my listening back in the Winter months. Finally before talking about my plans for the Summer I'll be disclosing my Favorite Mid-Range Portable for the Spring!

After which we'll switch gears and start with my first look, listen & review of a modern Flagship DAP, as during the Summer of 2018 I'll be focusing more on Top of the Line Portable Products!

We will start with the Cayin N5 Mk2ii which launched in late 2017 and is the third generation of the N Series players and the next step up from their N3 which I reviewed and lauded for it's plethora of digital features earlier last year. Priced at $369.99 from MusicTek via Amazon and built around a dual ESS 9018mk2 DAC Chipset and equipped with both a slow and sharp roll off filter in addition to both analog and digital line out options plus an Android 5.1 GUI. The N5ii offers a highly competitive set of features at this price point, it'll even function wireless as a Dac/Amp with your smart phone via BluTooth!

Overall the sound signature of this device is on the leaner side of neutral with exceptional low end texture and tautness, the digital filters do make slight changes to the presentation.

• Sharp-Roll off is;
• More aggressive
• Slightly brighter up top 
• Leaner Mid Range
• Emphasized macro dynamics and macro detail
• Exceptionally precise imaging but slightly disjointed
• Slow-Roll off is;
• Ever so slightly laid back
• Smoother Up top
• With no loss in texture
• Slightly wetter and more resolved in the mid range
• With a slight emphasis on micro detail
• De-emphasizes ambient noise
• More balanced with macro and micro dynamic changes/shifts 
• More cohesive imaging with a slight lack of precision compared to Sharp-Roll off  

Overall I felt the N5ii performed best with the Slow-Roll Off filter and a more neutral or lean sounding headphone, as it retained a very taut low end but become much more natural in the mid range and top end! How ever with darker and/or more laid back headphones the Sharp-Roll Off filter works better.

In terms of sound quality compared to the Fiio Q5 I found the N5ii advantages are that it is;

• Supremely consistent 
• Marginal difference in the quality of the balanced and Single Ended Output
• Balanced was simply a high powered output there for the loads that needed it
• No change in quality depending on file format
• Neutral Presentation 
• Offering two digital filters to tailor the mid to high frequency tonal balance to your tastes 
• Consistently taut low end regardless of filter choice
• Never presented any kind of hazy or stuffiness 
• Exceptional Resolve
• Presenting more micro detail overall
• consisting presenting more vivid micro and macro dynamics overall

In terms of tonality the N5ii presented;

• Drums
• With slightly less body but more impact and definition.
• So the size and mass of a timpani was more apparent
• Bass Guitars
• With noticeably more punch
• Better texture/resolve of the strings themselves
• So harmonic content added from fretting was more vivid
• Slight tapping or percussive sounds from fretting where also more evidant
• Finally the slight metallic twang of the metal strings were more vivid
• Less BODY but more power
• Lower notes were not quite as brooding or dark but,
• They were felt more forcefully with the N5ii
• So EDM was funner and more enjoyable with the Q5 but most natural/electric instrument based music was just more resolving/better with the N5ii
• Guitars [Acoustic & Electric]
• Slightly Drier
• But with improved clarity and more vivid harmonic content
• Again fretting was more vivid
• The texture of how the musician plays or strums each string is clearer 
• Harder
• With a more defined envelope overall

So forth an so on, just in general I found the Q5 to be rather lack luster... it's acceptably neutral but more or less kinda soft with the USB input. An the USB input is how I primary use a DAC/Amp.

Compared to the Shanling M3S the Cayin N5ii was in an entirely different league! Quite literally everything is improved, the User Interface has more power and options plus I think it's even easier to use. The sound quality from both the 3.5mm and 2.5mm outputs were better. The N5ii also supports more digital output options so the only reason I see to recommend the M3S is if you plan to use the Line Out. As the line out of each was... not as drastically different. 

Specifically the with my K702 and Pico Power in hand I found theN5ii Line out differs in that;

• The Slow and Sharp Roll Off Filters attenuate the Top End
• Where as the M3S filters are Low Pass and attenuate how the Bottom End is Presented

Overall though in every instance the N5ii has a tauter more natural and detailed low end. The only potential benefit to the M3S is it's lack of Android, as I understand that some of you simply have NO desire to own an Android based Digital Audio Player.

So again, if your budget is constrained to something under $300 or your HATE Android based Graphic Interfaces, than yes the M3S is quite good. But if you don't mind Android and can stretch your budget an extra $90 you'll find the N5ii is really a better product overall.

What surprised me the most during my time with the N5ii was how well it compared again'st my Geek Out V2+, though the two do share a similar DAC Chipset and digital filter suite. I did find that hardware aside, the inclusion of digital filters on both helped each to adapt to the music. In some cases the Sharp Roll Off Filter on the N5ii helped better define the audible image of music that is already mastered very "naturally." An in other cases the Blue Filter of the Geek Out V2+ would do much the same, present a slightly less natural tonal balance in exchange for a more defined audible image. Also each had a high frequency roll off filter that created a more natural sounding, slightly less aggressive and more defined sound with brighter/leaner headphones.

But not considering the digital filters impact I found;

• The N5ii's singled ended output was simply;
• cleaner
• the trailing end of each and every note played by a guitarist is more vivid
• more natural
• brass horns retain a nice bite without ever being too metallic
• more resolved
• a blacker background allows micro and macro detail to become more apparent
• more nuanced 
• precision in the placement of sounds within a space are more tangible
• Like the sound of the crowd in a live recording
• Just plain better
• The balanced performance of the N5ii was consistently behind that of the Geek Out V2+ in that it lacked;
• Nuance and resolve overall
• Again, while tonal balance imaging cohesion and precision are comparable the Geek Out v2+ was almost always more resolving of micro detail overall
• Each how ever presented Micro and Macro details with a fairly similar level of resolve

Now I also compared the Line Out of the N5ii to the balanced out of the Geek Out V2+ and while I found using my HeadAmp Pico Power helped close the gap in detail, the Geek Out V2+ was still better. How ever I did notice with the Line Out the N5ii was in every instance more defined, more powerful and just simply better at presenting low frequency information! 

So while listening to my live rip of Hotel California & the N5ii I noticed;

• More power on the trailing notes of the big drum as it came to rest after each hit
• Cleaner translation of fret noise/action on the bass lines

So in my final days with it I really found my self personally torn between having the N5ii Singled Ended with my Pico Power and ES10 operating single ended or just running the ES10 Fully balanced out of my Geek Out V2+. For some genres of music I would rather have that better low end detail and for others I valued a slightly more resolved mid to top end presentation.

Either way in terms of sheer value the singled ended output of the N5ii by it self was what stuck with me the most! I'm used to the madness of my Portable Audio Towers, but for many of you they elegance and simplicity of a truly high performance single box solution is what'll you'll reach for most!

Fiio's Q5 is a portable DAC/Amp featuring a dual AK 4490EN Chipset and a focus on wireless connectivity via BluTooth. Priced at $349 via Amazon, the Q5 also has a module Amp design with a dedicated 3.5mm sigle ended line out, dedicated digital Coax/Optical input and both 3.5mm single ended and 2.5mm fully balanced output for the headphone amp section.

In terms of sound quality, I found the USB Performance to be some what stuffy or hazy sounding, as I mentioned previously. Overall it's performance was most impressive with Optical In and many of my subscribers and readers were also impressed with it's BluTooth Quality. Non the less with a hard wired optical in I found the Q5 to be;

• Fairly Neutral
• Tonality did change slightly depending on the file format
• At times it was very natural
• Other times it was a bit hard and rougher sounding
• Having a thicker full low end
• Fairly Smooth on the Top
• Quite cohesive with good precision 

So if you happen to own an older Digital Audio Player like the ole school iRiver Models the Q5 is a great way to use their Optical output and breath life back into them! I in-fact really enjoyed the pairing of the Q5 with my own iRiver H140. I had a Source with lot's of storage and a quick Graphic Interface and a DAC/Amp that I could pair it with so I got the best out of both devices!

I also enjoyed the Q5 with my wife's iPhone. It's included iPhone friendly Case was super convenient, so in terms of pure convenience for iPhone users the Q5 is un-matched! 

So if your more concerned with ease of ownership than you are sound quality, I have to say the unique iPhone Case for the Q5 was the easiest portable solution to carry. As the phone retained full functionality with the DAC/Amp tucked  neatly away behind it. 

Finally, you may notice I didn't feature my HD 800 in any of these portable systems. In each it either sounded less than ideal or just couldn't get up to volume. I still feel that the Aune B1S with any good Digital Audio Player is hands down one of the best portable amps in the mid range price point for driving leaner headphones like the HD 800!

Next though let's do a quick recap on some of my favorite entry level devices.

An pictured above are still my two favorite products in the under $200 price point. 

The Shanling M2s for it's;

• Easy to master single handed operation
• Phenomenal Analog output

And the iFi iDSD Nano Black Label for its;

• Assortment of Hard Line Connections
• Line Out
• Pseudo Balanced Via 3.5mm TRRS
• IE Match Port for super sensitive earphones/iems
• Spacious & Airy Presentation
• Adjustable tonal balance via the Measure & Listen Filters 

But overall out of everything I've heard since the Winter of 2017 and up to the Spring of 2018 I have to say it's the Cayin N5ii that's impressed me most! So if your exploring portable Audio Solutions this spring I cannot recommend the N5ii enough! Price aside it's performance was phenomenal, but when you consider that it's just $370 as of this writing! It easily blows the competition out of the water, truly a high fidelity jack of all trades player combing the excellent suite of digital options I appreciated about the N3 with an exceptional analog output stage. 

An with some relevant experience in Mid Range portables I'm happy to say it's time I dip my feet into the waters of Flagships!

The last time I purchased a player I went for a flagship, so I felt that before I start reviewing them again I should be familiar with at least some of what's out there for those of you who want a little more bang for you buck. 

But moving forward I'll be focusing less on value, convenience and ease of ownership and more on end game fidelity.  

Without further ado let's dive into the Questyle QP2R!

Packing is modest and it does the job, also a thank you to Todd The Vinyl Junkie for setting up this QP2R Tour!

So some background on the Questyle Dap, unlike traditional circuits, Questyle opt for Current Mode amplification. In short if my understanding is correct, the Voltage levels are fixed and the current is what amplifies. Unlike a traditional amp design in which the Current is Fixed and the Voltage is what's amplified, either way it operates in a pure Class A "current mode." The Questyle website has more information for those inclined! 

Another unique feature of the amp is the Bias Control, again when the amp's under a heavy load setting the Class A Current Mode Bias to High helps to eliminate high frequency harmonic distortion. An most of you know that excessive distortion translates to noise, so any time we can reduce added distortion there are audible benefits assuming the load is "heavy" enough. Either way for my listening purposes I kept it set to High always. As a result battery life has been a little less than what's quoted but nothing too unmanageable.

Seeing as this is my first foray into Top of the Line Digital Audio Players I tested this one again'st quite a few of my own home systems and headphones!

How ever I only listened to the QP2R with it's 3.5mm Single End and 2.5mm Balanced Out. I didn't test it as a USB Driver Dac Amp nor did I use the Line Out Settings... but I think you need the HiFi Hub to get that feature... which I'm not a fan of. With the HiFi Hub the total cost of the unit creeps upwards of $1700, and while price isn't my concerns it's the very stationary and cumbersome nature of the Hub and the price increase I don't like. I got portable for well portability! Having a built in LineOut without any additional bulk means a lot to ME and those who will be using this as both an analog and digital source. Non the less though, at it's $1300 price point functioning purely as a standalone Digital Audio Player I do have to admit it's performance is stellar! Well worth the asking price.

I found that with my HD 800 and the 2.5mm balanced output the QP2R had;

• Exceptional naturalness in the mid range
• Listening to Epica's The Divine Conspiracy I heard details in Simone and her husbands voice I'd not heard before!
• Exceptionally low noise
• Or it presented a very black sound
• Silence was inky and this lack of noise again lead to exceptional resolve
• Textured but smooth response
• The overall lack of distortion really yields a smoother well resolved sound in both the mid range and upper end
• No lack of detail or extension in the mids and up top, rather slightly more detail than I was expecting with no added harshness or grain
• Fatigue free listening
• Fairly Soft Low End
• Sufficient definition and texture, but slightly lacking in solidity and power
• Kick drums lacked that "KICK" and an aggressive bass guitar riff was a little smeared
• Cellos and Painos had beautiful timbre, tone and texture but again electrical instruments and percussion were slightly soft
• Lack of Headroom
• With my most dynamic tracks I was only able to get an average of 83 dBs about 4 less than what I prefer to listen to [87 dBs averaged]

I also ran the Audeze MX 4 balanced out with an OCC Copper Cable from the 2.5mm on the QP2R, I found it to be;

• Clean, Clear but could extend a little deeper
• Good power and slam with exceptional texture!
• Here is where I found the High Bias to make a noticeable differance
• Electric Bass Guitar riffs were dynamic, punchy with good bitw
• Kick drums had IMPACT
• An larger drums like the Timpani had a powerful heavy but slightly hollow sound as I expect them to
• Though some of the deepest notes were slightly withdrawn
• Energetic Up Top
• Had just enough clarity and presance
• Percussion was snappy and never harsh 
• Natural Mid Range
• Again beautiful smooth but textured mid range
• Harmonic content resolves nicely, beautiful release on guitars, vocals and stringed wood body instruments
• Vocals have a nice little bit of added sweetness to them
• Intimate still but spacious 
• Precision is acceptable but cohesiveness and clarity in resolving complexly layered content is evident 

With some a little more efficient I felt the QP2R really shined, it's natural and smooth but still dynamic and detailed presentation came through better with the Gain set to medium or lower and with more efficient current hungry planars than more voltage hungry dynamics like the HD 800 which often couldn't quite get to reference listening levels nor maintain a solid low end. 

Ultimately though, with two different loads I deemed the QP2R to always present;

• An exceptionally low noise floor
• Inky black background 
• So much so that there were some details presented to me by the QP2R that I'd not heard before out of my own home system!
• An upon level matching I did in-fact identify such details in my home system but the slight addition of added noise made said details fall just shy of my notice in previous listening sessions
• Exceptionally low distortion 
• Allowing for incredible resolve with no added fatigue or harshness
• Both Micro Detail and transients were exceptionally vivid
• With no lack of dynamics
• Natural Timbre and tonality
• Again both the fundamental and harmonic content of instruments and vocalists alike were always crystal clear
• Optimized for more Efficient Loads
• Often running out of steam with more voltage hungry loads
• Often losing some extension on the very deepest reaches with quieter tracks

So simply put, Questyle's newest reference digital audio player does everything we'd want it to! In my case it replicated and sometimes exceeded the quality of my own home system! It's only faults lie in a slight lack of power overall and definition down low. 

Switching to my home system some of what's gained or clearer in the mid range and up becomes some what less vivid but there's added vividness and clarity down low. So again, I'm impressed given how small the unit is that it keeps paces with my current reference system.

Non the less, let's get into more specifics on how the QP2R compared to my other systems! Both portable and desktop. 

Starting with my my Singled Ended and Mid Range Portables

With my Modded ES10 the QP2R;

• Simply out classed the Singled Ended Shanling M3S & Aune B1S system completely with it's own 3.5mm Single Ended output
• Simply out classed my Geek Out V2+ with it's own 2.5mm Balanced Output

Which I was a little shocked by, as my Geek Out v2+ gave the Hugo 2 [USB\] a run for it's money, in this comparison the QP2R showed no mercy and clearly beat the Geek Out V2+

How ever with my Single Ended HM901/HeadAmp Pico Power system I found that;

• The HM901/HeadAmp Pico Power System was overall better
• Had a more linear response
• Powerful and taut low bass
• Very Clean slightly drier mid range
• Better Top end extension
• Where as the QP2R fell a bit behind
• It wasn't any quiter or blacker
• Had a slight forwardness in the mid range that's apparent with this super sensitive OnEar
• Had a slight over-emphasize on ambient noise
• Not so much mechanical noises but stuff like floor board creaking
• In a sense these details were more vivid but overly so
• Just fell short of drawing me into the music 
• Technically it wasn't up to par with the HM901/PicoPower System
• An the Timbre was as inviting as the with HM901/PicoPower System

So that kinda threw me for a loop! As it would seem the QP2R handles what I would consider moderately difficult loads best. As with the sensitive ES10 and the Difficult to Drice LCD 2 PreFazor it didn't wow me like it did with the MX4 and HD 800.

Speaking of the Pre Fazor LCD 2, output from the QP2R

• Again out classes the Geek Out v2+ in terms of technicalities
• However the tonality and timbre were noticeable drier and kinda shouty?!
• So Your preference tonally may dictate how much you appreciate the improved technicalities 

However compared to my HM901/PB2 System the QP2R falls a little short every where but the bass ironicaly;

• Tonality is noticeable drier
• An some how less natural than the Hm901/PB2 System
• Background noise is reduced
• So micro detail is sometimes better but odd tonality often skews some transients
• Ambient noise is exaggerated
• Again the normally the LCD 2 is quite dark, but for some odd reasons with the QP2R it's noticeably brighter
• Macro Dynamics are also some what exaggerated at the expense of micro dynamics
• Bass is quite textured however
• I'm assuming it's because of the slightly more difficult load requirements of the current hungry Pre Fazor, 

All in all I'm finding that I prefer my PreFazor LCD 2 on both of my ESS Sabre portables that have the high Frequency roll off digital filters. 

So all in all I feel that with more modern offerings the QP2R would do well, with loads that are more standard. As the ES 10 is hyper efficient and the LCD 2 PreFazor on the opposite end of the spectrum. So cans like the LCD 2F would pair very well with the QP2R as would things like the DT 880/1990 and Hifiman HE 560. Though let's move upwards to other TOTL systems in my home! 

Staring with the HD 800 vs the HM901 & iBasso PB2 System

Before we go further you should know my iBasso PB2 is modified with; 

• LME 49990 High Performance OpAmps 
• High Current Buffers
• Dedicated Portable Power Supply Unit
• The internal battery has been removed and all power is kept at a stable & Constant 16V

Non the less, compared to this portable system with the HD 800 I found the;

• Bass
• Tauter and more defined with HM901/PB2 System
• Namely big timpani drums maintained a great sense of impact and weight, while balancing the hollow resonant trails that follow each strike 
• Kick Drums hit harder, faster and had a cleaner envelope overall 
• Mid Range
• Quite dry on the HM901/PB2 System
• At times this was an advantage especially with Epica
• Where beautifully warm wood bodied classical instruments are  over laid with heavily distorted guitars
• Though at times it was a disadvantage 
• Such as with Rebecca Pigeon's Spanish Harlem where the timbre of each instrument was slightly drier than reality 
• Wetter but no less defined with the Q2PR
• With Heavy Metal the added wetness some times detracted from the aggressiveness of the track as a whole
• But with softer acoustic pieces the presentation was more natural with no "dryness"
• Top End
• Each unit had it's own advantages and disadvantageous 
• The HM901/PB2 system had clearly better top end extension which resulted in a better sense of pace & rhythm and time especially in percussion but it could also be fatiguing depending on the mastering
• The QP2R was smoother up top, so while it didn't always have that vibrant sense of presence, rhythm and time it was never fatiguing 
• Resolve/Imaging
• Volume matched each had no clear advantage over the other, how ever the increased headroom of the PB2 System allowed for "reference" listening levels at which slightly more resolve/imaging precision is possible  due to a more even tonal perception

Now compared to my Reference SET Tube Amp the QP2R;

• Only had the advantage of a blacker background
• Some detail in the mid range and up was more apparent but there was a lack of control and extension on the lowest registers of the audible spectrum
• More or less replicated and matched the cohesiveness and overall precision in imaging
• More or less replicated or matched my Desktop Amps sense of presence and tactility 
• Except in the lows
• My Desktop Amp consistently presented a more detailed more controlled low end 
• Struggled to provide sufficient headroom
• Again with tracks that had exceptional dynamic range the QP2R was not able to bring these tracks up to at least 87 dBs on average

But overall with my HD 800 I can say for the vast majority of my collection the QP2R made for an excellent single box solution for some of you it's added simplicity and blacker background may be preferential over having a bulkier portable system with slightly more noise but sufficient head room and more controlled lows. 

In either case Questyle certainly designed this product to very exceptionally match a desktop system on the go! 

 Moving to the MX4, with the HM901/PB2 System I noticed;

• Bass
• Tighter more and more controlled over all
• So big drums had more power
• Kick drums had more impact
• An large stringed instruments had a slightly more resolved or more audible fret action
• Mids
• Mid-range quality on each was fairly similar
• The QP2R was a smidge wetter and more natural so with a drier master or set of instruments it sounded more Natural
• Where as the HM901/PB2 System was drier so with a wetter master, or a set of instruments with a lot of harmonic content THIS system sounded more natural
• Highs
• With the QP2R system the MX4 did lose some vibrancy up top 
• Where as the HM901/PB2 System was no less smooth but more vibrant
• I feel this has to do with the rougher presentation of the HM901 System combined with it's own HF Roll Off Filter allowing the texture of slight over emphasis to be present without the fatigue 
• Resolve/Imaging
• The QP2R did take a slight edge forward in overall resolve because of it's blacker output
• However the more defined low end with the HM901/PB2 System did help to retain better precision in imaging 

Now comparing the QP2R to my own Reference Hybrid Tube Amp

• Bass
• Again better power and extension
• Mids
• Now this is where things get interesting as;
• The QP2R is equally natural but presents a slightly clearer more defined envelope
• Allowing for the texture of stringed instruments
• The unique vibrato of a vocalists
• The unique harmonic decay/release of guitars
• An other micro detail present in the mid range was a bit more resolved
• My Project Ember II with a Classic Grade Psvanne CBT 181-T Mk2 was;
• Fuller but not as detailed... period
• Highs
• Again the QP2R was;
• Clearer with a sharper attack
• Where as the Ember II was;
• A little smoother without as much emphasis on the leading edge
• Resolve/Imaging
• Now dynamics are were the QP2R falls slightly behind the Ember II as;
• The Ember II more clearly resolved micro and macro dynamics
• An in many cases the Ember II was able to very realistically build to a crescendo
• Where as the QP2R was;
• Sharper but a tad over enthusiastic at times
• Struggles with an accurate presentation of Pace, Rhythm and Time
• Failed to draw me into any passage of music that gradually builds tension through changes in volume
• However overall detail and precision in imaging was fairly similar between each
• Again the QP2R has a blacker background
• But doesn't seem to respond as quickly to the demands of busier passages of music
• Where as the Ember II is a bit nosier
• but handles changes in amplification needs more linearly, how ever add noise kinda nullifies some of the advantageous it has here 

All in all I'm quite impressed with the QP2R, while I found it's lacking in some digital convinces as a purely analog digital audio player it's excellent! Seeing as I personally prefer my DAPs run purely offline and exclusively in the analog domain I feel that the QP2R is totally deserving of it's flagship status!  I've always been a dedicated DAP & Line Out To Portable Amp guy but with the MX4  and Questyle's excellent on board current mode topology I could happily accept this as my end game reference portable!