iBasso CF01 Bluetooth ear hangers for your deluxe and not so deluxe MMCX IEMs to hang like so much splendid jewelry from your meaty aural cones.

Lets get one thing straight. I like my cables. Solid, sometimes pretty, sometimes lengthy and wide in the girth or short and stumpy and unsatisfying for some.

‘Do you want to review this bluetooth xxx’ has in the past been often met with a no or a meh - but lately Bluetooth devices seem to have come of age. Both the sender and receiving portions. I have recently been sticking a toe in here and there and testing the waters.

Some bluetooth dac/amps seem to be doing the job well, daps are a hit and miss often and earphones seem to be where its most at in terms of development and popularity. 

Mostly on the train in Tokyo i see bluetooth in ears of all sorts. I don't see many headphones these days. And of course cabled earphones mainly of the easy to procure variety.

So here i am. iBasso offered to send their latest foray into a brave new world and i decided to accompany them on a journey into a personal hell. That of a wireless future.

I am such a backward luddite.

At least Musk hasn't  got his brain plug in for retail yet...

Unboxing - for those with eyes to see.

Note the codecs available.
I am using AptX mostly.

A quick start guide and a charging cable.

The case is handy not only as a storage system, but also charges the device and is large enough so the user does not have to disconnect the earphones. 

USB-C for the win. If i wanted micro usb i would move to the Shire and go walking to Mordor.

A warranty card for future peace of mind.

Sleek and smexy! Sound impressions aside these are a pretty pair.

The first click on and off is slightly stiff,
After that it seemed perfectly snug.


Pairing seemed quick and easy. Open the box and off you go.

If you have any issues - hold down the right earpiece button for ten seconds. (Past the turning off stage) for RESET.

Addition trouble shooting (general Bluetooth device information):

Delete both of the L and R from your phone or dap. Put them back to the charging case. Then take them from the charging case and pair them again.  
If this does not work reset both of the L and R with a long hold on both, turn the Dap/phone off and back on and then pair in the normal manner.

Yes, pairing was super easy.
Thankfully...so that kept me happy.

Connectivity with the iBasso DX220 was stable.

Shake your head!

The iBasso passed my unofficial at home vigorous moving of my skull in all directions, some music-less head banging and also some jumping about.

They stayed in place nicely.

Quite comfortable around the ears also with their rubber covering. Lightweight also.

The bonus of being able to choose which IEMs to use is a plus also. I can choose first for fit and then the sound signature which i feel like listening to at that time.

iBasso testing has found “ With an iphone 11 we have tested it and get over 40 feet through 2 walls.”.

Lets go for a run as the Tokyo summer approaches 35 degrees at midday.

Luckily i went at around 9am for a warmish 29 degrees jog. A personal exercise renaissance which began with the onset of coronavirus.

Once again the CF01 stayed in place easily as i huffed and puffed my way around the neighborhood.

Connectivity was strong with only the odd drop off which reconnected again by itself easily.

Fit is comfortable, even with a mask.

A hat covers my overly eager do it yourself overly short at home covid-19 short back and sides hair cut.

Price is around $180 - $200 for the iBasso CF01.


The sound of the CF01 is limited by it being Bluetooth (and not cabled), and also the selection from available BT codecs chosen.

Source (Music files and dap) also plays a part towards quality i believe.

The CF01 is neutral with a lean towards reference. It is uncolored in the sense that ones earphones deliver their designed signature. 
No added bass bump or anything.

Simplicity itself.

Although i will not abandon my cable fixation do consider me newly converted  to the world of bluetooth convenience. 

Thank you to iBasso for sending Head pie the CF01 for review.

disclaimer:  Little dot is opening a US based web site and store and was looking for reviewers on this side of the pond to help promote their product line to the American market.  I agreed to do so based on previous experience with Little dot’s CD transport and Amplifiers.   Their tube amps have been a mainstay of the budget (and not so budget) headphone enthusiasts recommendations for quite some time, but to my surprise the first thing Little Dot wanted to send was their earphones.   I’ll admit, I’ve known of Little Dot for most of 10 years, but never realized they make earphones, let alone four different models thereof.     I was sent the 4 models of in-ear by LittleDotUS for purposes of review.  I have not received any other renumeration or input from Little Dot on the content of these reviews.

Each model in the Little Dot / CU Audio line is designed with a different target in mind.  The Wyn was designed from the ground up with EDM and house music in mind, while the Cen was designed to excel with vocal and choral music.  The KIS was designed with the idea of creating the best possible signature regardless of cost, while the Rad was designed a an introduction to Little dot and Audiophile listening at the opposite end of the cost spectrum.   Here you will find all four reviewed, but remember the one you are looking at now was designed to be a cost no object flagship in-ear with a current retail of just shy of 600USD.

Unboxing / Packaging:
The KIS shares its packaging style with the Wyn and Cens models using the same box and largely the same kit.   The box is a bookfold design with the  Little Dot name on the face and the CU Audio fairy logo beneath it.  Specs are all on the inside of the books cover and not visible on the package exterior so clearly not a stand-alone retail package for western shelves, but all the information is there once you open the package.   The kit is all nestled in foam in one of two provided cases.  The first is a hockey puck sized round metal case with the CU Aud logo on the top while the second is a pelican style (although not waterproof) snap closure polymer box that is slightly larger and rectangular.  The polymer case has about 50% more internal capacity so those wanting to take accessories may prefer it over the smaller metal case which has room for earpieces and cable but little else.    The kit that comes with the KIS is quite complete and has an interesting twist not seen often.   The cable is a heavy braided cable with a 3.5mm balanced termination and 2.5 and 4.4mm adapters as well as a converter for 3.5 single ended use.    Typically a TRRS 3.5mm jack is seen on cables with mics with a balanced 3.5mm being much less frequently seen.  For this reason some care needs to be used when plugging in the Wyn as use of the balanced plug in a single ended device may result in problems for the earphone, the source, or both.    The remainder of the kit includes a robust shirt clip and six different sets of silicone tips (7 total including those on the KIS).

At first glance, the Kis looks a lot like its brother the Cen, but on closer inspection, the Cen is a barrel shape while the Kis is more pill shaped. Think of a large advil with a connector and nozzle attached and you have a rough feeling of the shape.  The shell is aircraft grade aluminum and is composed of 3 parts, an outer shell, an inner shell, and the nozzle assembly.  All are anodized and well matched in a brilliant red.   seems are hard to feel or see so the unit looks to be one piece until a closer inspection is made.   There is a vent on the under side of the shell and a second at the base of the nozzle that help tune the sound.   The Nozzles exit the mid point of the under side with a very slight upward rake.  There is a pronounced lip to aid in tip retention as well.   Connectors are the .78mm raised bi-pin type and exit the top rear with a 45º forward angle.  This arrangement is clearly designed for tip-up wear when paired with the cable that angles upward.   Overall fit and polish befits a flagship as it is very tight and clean.   For me, the Kis smaller size and slightly deeper insertion made it an easier fit than its brother and I enjoyed wearing these for extended periods without fatigue setting in.

The KIS is a hybrid in-ear utilizing a 10mm dual diaphragm amorphous diamond-like carbon dynamic driver and a pair of customized balanced armature drivers.  Per Little Dot, the shell design is also integral to the sound with the venting and positioning of the drivers tuned to provide the best possible sound.    The housing uses a multi-layer internal structure to reduce resonance and reflections.   Nominal impedance is listed as 18Ω with a sensitivity of 105 dB/mW.  I found the KIS easy enough to drive well with a phone or tablet and while it scales well qualitatively it does not need a lot of extra power to do its best.

As previously mentioned, the provided cable is terminated as 3.5mm TRRS balanced with adapters provided for 3.5mm Single ended,  2.5mm balanced, and 4.4mm balanced connections. The 3.5mm jack is straight with the adapters all 90º which creates a large L shape as it exits the dap or phone.  Worth noting is that this arrangement is capable of putting a lot of pressure on the jack in the source device especially the 2.5mm that concentrates that force into the smallest possible area.  So while this arrangement is very versatile, some care is required to be certain pressure is not applied to the adapter accidentally and transferred into the source device.
The cable provided with the Kis is 6N silver plated Oxygen free copper (OCC) in an four (4) strand braid from the jack (black metal knurled housing) to the matching splitter.  Above that, a matching chin slider holds the 2 strand twists that run to the earpieces.   The hooded .78mm bi-pin connectors are encased in black plastic with a large L/R marked on the inner surfaces.  The cable does not have preformed hooks but the connector housings are angled for tip-up wear.  I Found the cable to be high quality befitting the flagship model with little memory or tendency to tangle when coiled for storage in the hockey puck style case.

The sub-bass has good rumble and is mildly emphasized here but not aggressive or dominant as it disappears into the background when not called for.    I found roll-off in the mid-30s, with everything above that point (sub-bass) nearly linear as there was not a pronounced emphasis at 50hz that wasnt present at 100hz as is common.  Instead, sub-bass is linear and then the mid-bass slowly steps back as it moves upward.    Mid-bass has good speed and texture and is well controlled with no slop or tendency to slur or thicken.  Transition from mid-bass to lower mids is very clean with little bleed and no obstruction.  This is the kind of bass elevation I can appreciate as it emphasizes without trying to take over the joint.

Mids sit slightly behind the bass and treble but do not sound recessed so much as a bit less emphasized.  Here we have good detail and a very natural tonality that is the biggest plus for the Kis in my estimation.   Lower mids have good weight without feeling dull, while strings have good energy and timbre, and higher vocals have a bit of a push but not so much to make female vocals stand out unnaturally.   I found the Kis to be a good listen for piano and violin concerto which I think may be the hardest two things for any speaker or earphone to reproduce accurately.  While the Kis isnt perfect in its tonality for piano, its a lot closer than some models I have tried that cost substantially more.

Usually with an upper-mid push we expect a lower treble elevation as well but the Kis doesn’t follow that pattern instead it levels off almost immediately as you cross from upper-mid into the treble and stays fairly level for the entire range of the lower treble before stepping back a bit above 5kHz or so.   Final roll-off was somewhere between 12kHz and 13kHz to my ear although the documentation claims it significantly higher so my hearing may be limiting my results.    Snare has good rattle, with very sharply defined edges but lacks just a touch of impact on the initial attack.  The flute in “Hunting girl” – Jethro Tull was very well rendered with good tonality and without any tendency toward stridency which also tends to be a tough combination to master.   Cymbals have no metallic edge but like snare could use a touch more energy to sound completely natural.  I think both of these instances are a planned trade off of that last bit of energy for a smoother presentation.

Soundstage / Imaging:
Stage on the Kis has roughly equal depth and width and a good amount of height to the mix.  Overall the Kis has a stage like a small auditorium rather than a giant concert hall, but has good proportion.   Seating the orchestra is straight forward as instrument separation is above average and I found no errors in placement on the stage or overlaps that wouldn’t naturally occur.   Layering is good was well with no compression as passages got faster and more complex.  Imaging was well defined with spatial cues being easy to track and position on the stage being easily identified.   Overall, not class leading, but solidly in its class in all aspects.

Thoughts / Conclusion:
I expected good things from a DLC dynamic and a pair of custom tuned armatures in a housing that took 3 years to develop.   When your advertising states “18 months of product development, over 160 testers and 14 rounds of beta listening meetings, and total of 86 versions tested.”, you don’t expect to find any rough edges left by this stage.    The Kis largely delivered on that promise so I have to say for a new line of products from Little Dot, they made quite a splash.  This one is easily my favorite of the four models not because of its flagship status but because of its closer to neutral tuning and more detailed mids.  
There is a ton of competition in the price range of the Kis and while I can’t say it hand’s down walks away with the prize, I can say it competes well and gets in enough punches to stay in the fight with everything I have tested in the 600 dollar range.   Again, for a first effort competing against competition with 20 and 30 years of product experience, that is impressive.   The Kis brings clean bass with good rumble and slam, detailed mids with good tonality, and a slightly polite treble that won’t scare off anyone but still brings enough air and top end to keep it from sounding closed off.   Build is first rate as well and the kit is better than many at higher prices (and vaguely reminiscent of the Pola39).     If you get a chance to audition the Kis, you should, you just might go home with one.

Pros:  quality build, impressive kit,  mature detailed tuning
Cons: cost, slightly polite tuning wont please all.