DDhifi TC44A, TC09S, TC28i Pro, and BC44B

TC28i Pro lightning to usb-c OTG and Power adapter

https://www.ddhifi.com/productinfo/1350761.html | Amazon, $49.99

This lightning to usb-c adapter is unique.  DDhifi already offers a regular TC28i model which allows you to connect usb-c OTG data cable to iPhone and iPod Touch devices.  This way, for example, when dealing with usb-dac dongles, you don’t need to buy usb-c to lightning OTG cable.  The only problem, it has a data only connection, and you can’t charge the host at the same time unless using a splitter for data and power.

This Pro model of TC28i adds another usb-c power port specifically for charging input.  TC28i Pro version has dimensions of 20.5 x 18.4 x 9.5mm (6.3g), a little bigger than original TC28i with 18.5 x 13.5 x 9.5mm (4.7g).  Here, you have a lightning connector going into your iPhone or iPod Touch and 2x usb-c ports, one for data (OTG) and another one for power to charge the device while using it with external dac/amp.  Pretty much, it is like a power/data splitter built into this adapter.  And, it also comes with its own usb-c to usb-c cable if you need one.

This adapter is perfect for use with power-hungry dongles that drain your iPhone battery, and now you can be charging your iPhone simultaneously.  I actually compared TC28i Pro vs the original TC28i while using Cayin RU6 usb-dac dongle, and, as expected, found the sound to be identical.  You can even use Pro model without power cable being connected.  But if you need to charge your host, Pro offers a convenient separate power port connection.  Btw, with or without a power cable, sound of RU6 with TC28i Pro was the same.

BC44B 4.4mm to 4.4mm interconnect cable

https://www.ddhifi.com/productinfo/1321702.html | Amazon, $79.99

Last, but not least, is BC44B 4.4mm to 4.4mm interconnect cable based on their NYX series pure silver Litz Type II high purity wires.  With a recent popularity of portable amplifiers, more people are looking into premium short cable interconnects, and this BC44B is one beautifully crafted cable.  Similar to NYX series, it uses 27.2AWG core wires (0.05mm x7 x7 strands) and thicker 24.9AWG spiral shielding (0.05mm x7 x14 strands), each one with a custom high quality inner and outer insulation.  But unlike their NYX series pure silver BC130A cable with 4 wires, BC44B interconnect has 8 wires braided in a neat square braid.  The cable is thicker and weight 15g (10cm in length), but it is still flexible and can easily bend 180deg.  They do offer other terminations, while the review unit I received had a straight connector with 4.4mm gold plated copper plugs and a custom chrome housing, laser-etched w/DDhifi logo.

I know, these interconnect cables are short and some people wouldn’t expect too much of the sound change going from one cable to the other.  But I still wanted to compare it to a few of my other premium interconnect cables from Eletech and DCH (both of which have a lot higher price tag), using Cayin N8ii DAP and C9 portable amp.

BC44B vs Eletech Iliad IC (silver, palladium plated silver, and gold-silver alloy) – Iliad has a bit wider soundstage and a touch more air in treble, while in comparison, BC44B gives sound a little more intimacy and a smoother tonality at the top.

BC44B vs DCH Silver IC – Here, the difference is opposite to the previous comparison, with BC44B having a touch wider soundstage and a bit more revealing tonality, especially in upper mids and treble.



The latest batch of DDhifi accessories provides a lot of useful functionality.  When I want to use my S22 with 4.4mm cables without a bulk of multiple adapters, I go for a tiny TC44A usb-c DAC/amp which looks and sounds great.  Or, since my iPod Touch battery is degraded and lasts only 10min, I don’t need to pause when using usb-dac dongle because TC28i Pro adapter has a separate charging port without a need for a cable splitter.  I’m also dumbfounded how TC09S usb-c OTG cable can improve the soundstage and imaging which is probably due to its extreme isolation of power and data wires.  And BC44B 4.4mm audio interconnect is just too damn sexy!

It is always great to have options and there are many other adapters and accessories out there.  But not too many of those are as compact and as cool looking as DDhifi products because this company pays a lot of attention to both, functionality and appeal.  I think it is great that DDhifi creates affordable audiophile quality accessories with a premium look.  But as I mentioned before, these are not accessories that just look good, these are high quality and functionality accessories that happen to look good, which is a cherry on top!  New IEMs and DAPs come and go, like a flavor of the month.  Quality accessories stay, being always in demand for use with new IEMs and DAPs.

3 thoughts on “DDhifi TC44A, TC09S, TC28i Pro, and BC44B

  1. So, will the TC28i Pro directly power a dongle DAC and bypass the iPhone’s battery? I’ve had clipping issues with trying to drive dongle DACs to loud volumes on the iPhone, and maybe this could be a fix. Also, considering the MFi09S’s steep price (at $65 USD, nearly double or triple other OTG cables), are the improvements worth the cost?


    1. Yes, TC28i should solve your problem. Regarding usb c cable, for some people $65 is like $5 for others, just like for some $5k iem cable is like $100 for others. You see where I’m going with this. I do like the improvement, but it’s not a must have.


  2. Sadly having some issues with the TC28i Pro, for some reason it will only work on my charger with the supplied USB-C cable, and not my longer Anker USB-C cable. The relatively short length of the supplied USB-C cable kind of limits its usability, in that you’re kind of tethered to the charger. Also, using the USB-C OTG cable that came with my Hidizs S9 Pro, it’s not bypassing the iPhone’s battery (which from the product description and box schematic, it’s clearly supposed to be able to draw power directly from the USB-C charger), so I’m still experiencing power issues by way of volume limits. I’ve emailed ddHiFi with these issues, hoping they might have suggestions on other cables.

    Possibly the TC09S might be a solution, but I’m hesitant to pull the trigger unless I know it’ll work.

    Just posting this as a caveat emptor, the TC28i Pro is clearly partial to the cables you use with it, and might be more of a headache to cable match than it’s worth. It also might not be capable of bypassing the iPhone’s battery, which is one of its major (intended) features.

    The MFi09S (the Lightning version of the TC09S) has a solid build quality and sounds good so far, although I’ve not directly compared it the other cables I have on hand.


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