I had the iFi Pro iCAN on loan for a few weeks and have assembled my notes below. They will remain mostly in point form, because no one wants to read an essay. I ran it through a fairly extensive gamut of different headphones and speakers.
Since there is a lot of "stream of consciousness" in these notes, it would be prudent to not examine any particular section by itself. At the very least, read the section immediately above it so you know where the relevant comparison is coming from.
Also be aware that in point form, my notes are very nitpickish. I do not dispense with pleasantries here, and my editing will be minimal. This is simply the style of my note-taking, so don't get your knickers in a knot if you disagree with something.
Main equipment used for evaluation:
Hifiman HE-6: well known as the most power hungry brute in the headphone world, and serves as my main reference can, low-ish impedance and stupid low sensitivity
Sennheiser HD650: my other reference can, and should be well known by most headphone users, high impedance and medium sensitivity
Sennheiser HD598: little brother of the HD650; horrible impedance curve
Nuforce HEM8: multi driver iem, low impedance high sensitivity
Fostex TH-x00 Purpleheart: closed, low impedance medium-high sensitivity
Bryston B60 - integrated speaker amp and my primary amp for the HE-6
Prism Lyra and Prism Callia - both pro level dac/amp, the latter being the "hifi" version with a more powerful amp
RME ADI-2 Pro - pro level dac/amp
iFi iCAN Pro - well d'uh
Stereoknight transformer based balanced preamp
Reviewer Bias:
- purist
- leans to preferring dry/clinical sounds
- snarky
Build Quality
- chassis overall very nice build quality; no complaints here
- casing is solid and feels good
- large rubbery pad on the bottom isolates it from the desk
- good feel to the volume knob
- very slight play to all knobs/switches, but nothing unreasonable
- gets warm but not hot; avoid stacking though, especially if it's a component underneath that needs to breathe since the rubber pad will insulate
- remote: cheap plastic thing, it works most of the time but doesn't seem to detect sometimes depending on angle
- switches are good, stick out just enough to be functional but not feel too fiddly or obtrusive
First listening impressions
- first: hey this is nice
- later: new toy syndrome has worn off, still good but not as enthused
- kinda brutish, not an ogre, but more Fezzik than Inigo Montoya
- I have a really hard time matching volume, because the iCAN "feels" louder all the time
- overall feels slightly on the V-shaped side (both warmer yet brighter)
On the inputs/outputs:
- the actual switching mechanism itself is quite seamless
- use the balanced XLR inputs; they sound so much better than the single ended
- I'm certain it's not my source, because mine does both and I've evaluated on other gear and found the differences to be marginal*
- single ended seems muted and loses energy (especially treble) and impact/punch compared to balanced inputs
* however, I cannot fully discount that this is a function of how my source is interacting with the iFi inputs
- but noise floor is higher with balanced input while using single ended output... not sure why this is; could be a cabling or power thing but it's unusual and I can't fully track it down
- switching inputs (both with nothing connected or the same source connected to both xlr and rca), there is a higher inherent noise from the balanced inputs which is opposite from expected
- however this noise is not affected by gain
- but it is affected by the pot... so the origin of the noise is coming from in between? It's not a huge problem, so I'm not chasing it down anymore after this
- balanced output is always quiet, regardless of input
Noise floor:
- not detectable with HE-6 (no surprise there)
- very slight noise floor with HD650 on balanced low gain with volume turned up all the way (can't tell with music)
- more noticeable with HEM8, but again it's low enough that your music would be deafening by the time you reached audible levels of noise
Impressions with HE-6
Note that my primary amp with the Hifiman HE-6 is the Bryston B60 which is a speaker amp. Most of my comparisons will be against that unless otherwise noted. Yes the HE-6 is a power hungry beast, so that makes it a good stress test so to speak.
General musings:
- in single ended mode, Callia and iCAN are somewhat close, with iCAN carrying more grunt but Callia feels more refined
- in balanced the iCAN pulls closer to the Callia in refinement
- Callia headamp is cleaner (single ended) while iCAN seems stronger and punchier (same impression from both HEM8 and HE-6)
Initial thoughts on Balanced vs single ended (HE-6) with the various options:
- no issues with power in either single ended or balance, it gets plenty loud
- initial feelings on all the various options and knobs: I am not a fan
- the character of the various settings actually changes depending on single ended or balanced
- typically I found myself preferring balanced solid state
- the two tube modes seemed stronger in single ended mode; going to balanced seemed to take out some of that tubeyness or changed the tone to something odd
- on Xbass and 3D most of the time the first setting is ok-ish, but anything higher I did not like
Mode: Solid State (single ended)
- does not hit as hard as the Bryston B60 (but more than Prism Callia)
- slightly more sibilant yet softer at the same time; the initial "sss" is stronger but the trail is softer or drawn out
- midbass has a slightly hollow impact (sort of like emphasized at both edges); I can see how this might make people feel it is more detailed and impactful
- so maybe this is simply how it handles a transient; harder front edge, perhaps more overshoot then followed by ringing?
- initial feeling is more air and more zing, but this fades after some time
- coming back to B60 immediately feels fuller and more balanced, even though it's hard to quantify and doesn't have the same "kick" as the iCAN
- overall prefer solid state over tubes after listening back and forth
Mode: Solid State (balanced)
- more power, seems to have more control
- feels a bit more full bodied, but it's a very slight difference here
- midrange presence seems slightly smoother, but marginally so
- upper range unaffected
- still doesn't feel as full as the B60, but brings a bit more kick to the game
- if I had to pick one mode of the six possibilities, it would be this one
Mode: Tube (single ended)
- definitely not neutral
- you can easily tell there's a bass hump/harmonics
- more thump (different from kick), but softer on edges
- pretty much what you expect of a stereotypical tube sound
- you'd think this would be nice on music that was a little bass light... but adding those harmonics into stuff that doesn't have it in the first place doesn't work and you get a harmonic warmth but not any actual body; it actually makes those mids feel... not quite honky, but too thick
Mode: Tube (balanced)
- less hump, less thump
- seems like less of a deviation from normal compared to single ended
- still warmer compared to solid state, but in a different way than the single ended mode
- let me rephrase... feels like warmer with a tilt?
- perhaps slightly cleaner sounding than single ended, but tone is slightly offput
- I find myself marginally preferring single ended over balanced in tube mode
mode: tube+ (balanced)
- so I thought: ok if you're gonna go tube, might as well go all the way???
- seems like richer deeper sound? nope I lied, that's not what I get
- not any thumpier or softer
- but definitely an extra harmonic or something that pulls on the ear in an odd way; I'm guessing it's odd order harmonics here
- upper end feels less refined
- it's not a treble glare, but maybe a high order distortion product
- I actually feel like this one is more fatiguing than regular Tube mode
- not sharp, but seems kinda hissy/sibilant
- feels like... a delay in the upper registers? (rather than harmonics?)
mode: tube+ (single ended)
- ok this one seems richer compared to balanced
- adds more warmth
- too much of a "good thing"
- midbass steps forward
- does not tame bright recordings; just smooshes it out
- feels like a reverb
- even as an outside listener while someone else is wearing the headphones, I could tell this sounded different
Crossfeed / 3D Holographic:
- bleh? maybe I'll try a different song... nope, still bleh. Maybe a different setting, wow nope What is going on. Let's try a mono recording... nope, now it's just further away.
- loses impact and sharpness
- I do consistently feel that there's less "centre", but it comes at the expense of everything else.
- Let's not pretend that we're emulating speakers here. I prefer the stock crossfeed plugin on Jriver, or better yet just get the free ToneBoosters Isone Pro vst plugin (but this requires all the software shenanigans)
30: dips the middle
60: dips the middle more
90: boosts the edges
- really not much more to say here; overall this mode did nothing for me
- but note for later, this feature redeems itself a bit on the preamp outputs
XBass:
- oh the lowest setting is kinda nice... but the others are just too much; in fact distractingly so
- even with metal recordings which I find are typically mastered bass light, the boost just didn't seem right
- you can't use this to correct for bass deficient headphones, because then you're pushing past what the headphones are really capable of and it turns into a muddled and distorted mess
- on bass-light recordings... eh I guess sorta it works, but you can't really amplify something that isn't in the recording
- so really this is only ok with bass capable headphones but bass-light recordings, and only on the first setting
- this feels like a bit more than just a typical EQ bass shelf, like maybe there's a tiny bit of harmonics added in too? I wouldn't be surprised if there were some crossfeed effect happening too, but don't know that for certain and am purely guessing here
- I suppose if you're in the "MOAR BASS" category of listeners then you'll be happy with this; I tried this using some bass heavy Fostex TH-X00 Purplehearts which are already bass heavy and this was simply too much
Gain (level match as much as possible by ear and multimeter)
- I'm surprised that it seemed like there were differences here
- low: kinda weaker? vocals seem slightly strained, but smoothest mid and treble, least impact
- med: "stringier" (not necessarily bad per se) upper end, impact seems cleaner
- high: hissier and slightly more sibilant, impact same as medium or ever slightly stronger, feels a bit like midbass boost again
- overall I stuck with Medium gain as my favourite and most of my listening was done here
Impressions with Sennheiser HD650
- all the fiddly knob stuff is less disagreeable on HD650 than the HE-6, like it's not as sensitive/resolving
- initial impressions seemed positive, but this dissolved after fifteen minutes
- soft touch/edges
- I thought it would be warmer but that's not the case
- still sounds brighter compared to my Bryston, it's not a "tss" sound but the trailing edges have a slight upturn to them
- resolution is ok, but not the best I've heard with the HD650
- Lorde - Royals: good kicks, but metallic, snaps don't have the body that they should
- all above impressions in solid state mode (balanced)
- Tube mode (balanced): ahh What?? distorted wonk wonk wonk
- Tube+ mode (balanced): huh better, like returning more to solid state, less sibilant, but slightly more fatiguing than regular tube mode
- SS mode (SE): sounds about the same as balanced, maybe a touch more metallic
- Tube mode (SE): warmer, hazier, this is the softest sound of all the modes and configs
- Tube+ mode (SE): too much harmonic, almost feels like an echo? even fuzzier, loses kick; vastly prefer balanced in this mode
- overall I do no not recommend the HD650 with this amp; it was not an ideal pairing
Other headphones:
Fostex TH-X00 Purpleheart (single ended only)
- this is a bassy headphone going into what I feel is a somewhat bassy amp...
- as expected combo produces too much bass overall for my tastes, but could be fun for others
- Xbass: too much; it overwhelms
- crossfeed: meh... too mushed with all the bass, it just makes things feel hollow in the middle and flabby everywhere else
- tube mode: is ok, definition goes down, but rumble and thump increase (no surprise there); if I wanted to go for a stereotypically tubey sound with lots of warmth, this is it
- tube+ mode: also ok; it's just softly thumpier, same definition as regular tube mode but has a softer tonality, not warmer but low end feels stretched out, upper end
- this would be a basslover combo
Fostex T50rp (single ended)
- just not a good match
- top end feels withdrawn regardless of setting
- midrange is there, but feels detached
- bass hits quite hard, this was about the only part I lked
- tons of power, but it simply didn't mesh well
- I gave up on this
Sennheiser HD598
- very similar tone as the HD650
- similar changes with the various settings, but overall effects are less so and this seems to work in its favour
- I would pick the 598 over the 650 with this amp
- solid state: single ended is good, balanced feels somewhat tubbier
- tube balanced: not as wonky as the HD650; I can tolerate this one
- tube SE: warmer, softer, lazy-ish
- tube+ balanced: like a slightly edgier solid state
- tube+ SE: mush mush mush, stick with balanced
- crossfeed is actually no too bad, the middle doesn't dip as much, overall feel is more like a sideways stretch
- Xbass: it's weird that the 598 feels more comfortable boosting bass than it's big brother 650; still not my cup of tea, but it's workable here
NuForce HEM8 (from the 3.5mm jack)
- the 3.5mm jack is lower in volume compared to the 6.5mm
- congested? what the heck is going on? I'm having trouble trying to do a volume match because something doesn't sound right
- no seriously, what's wrong with this thing... is it broken?
- loses cohesion
- snaps and plucks are in the wrong place in time???
- is this just some sort of L-pad going on to bring the level down? feels like something more than that
- in any event, the sound is a mess and I'm abandoning this
- reading the manual... oh this is the iEMatch thing? I have no idea what that's supposed to be, but it's clearly not working for me
3.5mm jack with Fostex T50rp
- not as messed up as the HEM8, but still feels slightly muted
NuForce HEM8 from regular TRS
- ok, so right away this is miles better than the 3.5mm output
- seems a bit bassier
- does not feel as neutral as my NuPrime uDSD
- midrange is flatter, treble has good extension if very very slightly upturned
- slightly cloudy in resolution...
- REVISED: balanced inputs cleans this up (don't know why, but the above when I was using single ended inputs the sound sucked)
- overall tone still slightly fuzzy, but not cloudy like before
- overall tone balanced is restored
- Callia headamp is less stuffy, like a veil has been lifted
- midrange clarity improved, feels much better and breathes
- bass hits harder and cleaner now
- all above noted with solid state mode
- tube mode: there's a tradeoff here... seems cleaner up top but muddier down low
- tube+ mode: wow big pop when switching mode here so be careful; did not get any cleaner like tube mode but did not get muddier either... but sounds withdrawn
- actually just be careful with sensitive iems with the knobs; they all seem to produce pops when changing modes
- Xbass: even 1st notch seems too much, 3rd notch gets distorted
- 3D: 1st notch collapses the middle stage and becomes withdrawn, 2nd notch not much different, 3rd notch adds elements to the side (but lower, unlike speakers which was placed higher) but still sounds artificial; overall staging feels better with this turned off
- Callia headamp is cleaner (single ended) while iCAN seems stronger and punchier
Impressions on Speakers
Speaker "3D Holographic" settings from the preamp outputs:
- does not have the middle dip like with headphones; general balance is better
- staging is better preserved than with headphones
+ mode: it's ok, seems to add more air? very tiny smear but yeah I guess it feels like a different room or speaker setting; placement of side instruments moves further out and slightly up; with a mono vocal and my speakers slightly offset, I can hear this distortion effect like a comb filter? (yes this happens with offset, but I've never heard it this apparent before and it disappears with the crossfeed turned off)
30+: feels like a reverb now, angle doesn't really change but speakers have moved further away
60+: really pulls it out to the side, it's gone past reverb and is almost like an echo; instrument location has moved further behind and up, a bit like I have some satellite speakers in a surround mode behind me; the middle is a bit of a weird null zone
- overall 3D effect is less noticeable in Tube and Tube+ mode
- with desktop speakers the effect is very noticeable; likely most of the processing occurs in the upper registers of the frequency range, so the entire speaker and staging flies out to the side
- the various bookshelf speakers I tried exhibited mostly similar behaviours (main ones I had on hand: Celsus Sound SP-One, Centrance Masterclass 2504, John Blue JB3)
- the one that sounded best was my John Blue JB3 which feels like a horn and has a very narrow sweet spot; the + mode expanded this and gave it more space (almost too much air, though the speaker veers that way to begin with)
Larger speakers used: Genelec 1030, Yorkville YSM8, Yorkville U15 (full sized PA cabinets), a couple Paradigm bookshelves
- with larger full range speakers that have a deeper reach, the 3D spatialization is not quite so drastic since the lower energy range doesn't move, thus helps keep things in place
- but the effect here is that I felt like I moved closer to the speakers (increasing effective angle) rather than have the speakers widen out
- it's still a bit hazy and/or feels buzzy out at the furthest edges and raised up higher (again like I have some small satellites above and behind me, though their location is much higher here than compared to the desktop movement); the middle isn't a null zone like with bookshelf speakers, but does feel squishy
- the better the bass reach of the speaker, the less egregious the effect of the spatialization
- sub integration is kinda odd though; I feel like I'm getting phase discrepancies and walking around the room feels weird, so it's probably better to stick with a regular 2.0-ch setup rather than 2.1
- but overall I find it easier to adjust my ears to the speakers with the 3D effects; with headphones it just doesn't work for me
XBass speakers:
- if you're trying this on desktop speakers, you're gonna push them past what they're capable of and get a horrible mess because you're just distorting the speakers
- this did not sound good with any of my small bookshelf speakers
- on speakers with very good bass extension, you'll get rumble but not impact, it does feel deeper but also like you're in a bass bubble
- my Genelecs gained body, but still the strain was showing
- with my full range Yorkville PA speakers, this was generously room filling
- like on headphones, I find the first notch ok, 2nd is passable, but third is way way too much
- also similar to my headphone assessment, this setting really only works when you have bass-capable speakers and bass-light recordings.
How about as preamp?
- I wish there were a way to mute the preamp outputs
- all the fiddly knobs pass through in their own way
- not as transparent as the Stereoknight (but this is one of the best preamps I've ever heard); feels slightly mushier in comparison
- SS (balanced out) - soft yet a bit hard somehow; feels like a slight V emphasis
- tube (balanced out) - softens the sound, sharp plucks and twangs are smoothed out
- tube+ (balanced out) - actually less soft than regular tube mode; there's roundness to the sound but not warmth
- SS (SE) - same as balanced; maybe just a tiny bit more definition?
- tube (SE) - ever so slightly different flavour from balanced but hard to describe
- tube+ (SE) - more warmth than balanced
Closing thoughts:
- no, I didn't hate it, despite my snarkiness
- I did not read other reviews before taking my notes, so my observations are fairly untainted
- solid state mode strikes me as a very competent amp
- preference for balanced vs single ended depends on the mode used
- there is an impressive amount of power on tap; it is rare that I find an amp that can handle the HE-6 and not struggle
- all the variable functions strike me as trying to do too much in such a small space; I understand the appeal and it's a tweakers' delight, but for me those added features were detractors
- just because I didn't like the Xbass or 3D spatialiazations doesn't mean others wouldn't enjoy them; the only feature that baffled me was the iEMatch