DD HiFi Carrying case and 3.5mm/4.4mm adapters

Audiophile fashion!

The products were provided free of charge for the review purpose in exchange for my honest opinion.

Manufacturer website:  DD HiFi.


If you think that audiophiles only care about functionality of their accessories, think again!  Of course, a storage case needs to be roomy and durable, and adapter needs to convert from one type of connector to another.  But doesn’t mean it can’t be done in style.  And that’s exactly how the newcomer, DD HiFi approaches design of their products.

While DD HiFi was started not too long ago, its CEO (Demond Ding) is a seasoned audio industry veteran from FiiO.  This connection actually makes sense since a number of DD accessories are designed specifically for FiiO products.  But they continue to expand their catalog with more goodies, two of which I would like to talk about in the following mini-review.

The Case.

We are familiar with protective DAP cases and IEM carry cases.  Many new products include these as part of their standard accessories.  But you still have to carry separate ones when traveling, and might need more to carry additional accessories.  Recognizing the demand to combine everything together, DD designed their C-2019 case.

With compact exterior dimensions of 200x100x40 (mm), it follows 2:1 design aspect ratio, and uses different materials to keep audio gear safe and secure during transportation.  With a combination of a softer material inside to protect the gear from scratches and bumps, a hard top and bottom cover to protect the gear from exterior force, durable YKK metal zippers, and fancy 1680D oxford bifilar wear-resistant fabric on the outside with a matching handle – the case looks practical and stylish at the same time.


Due to protective thickness of the walls, the case dimensions inside are 190x90x30 (mm).  The main section of the case is intended for DAPs, has 2 attached elastic bands, and 2 removable Velcro partitions to configure the rest of the space or to use it for an addition protection of the audio player.  I tried many different DAPs, including SP1000 which is the largest one I have, and was even able to squeeze in both LPGT and R2R2000, though it was a bit of a tight fit when I closed the zipper.  A more practical use is to store a DAP and a pair of IEMs with a thick aftermarket cable.


The cover panel of the case has more storage on the inside with 2 stretchable net pockets that are very handy for usb cables, adapters, memory stick, and any other non-bulky item.  There are also 5 pockets for micro SD cards, but the fit is so tight that I was worried it could damage the flash cards.  I would actually suggest to partition this area into 4 pockets instead of 5, to give more room for the cards.  Also, on the side of the case there is an opening to extend a headphone cable from inside the case, if the cable is thin enough.  For a thicker cable, you can position double zipper to create an opening for that.  This gives you an option to play your DAP with headphones plugged in, keeping everything securely inside the case while you are listening to a music.


The Adapters.

Today’s DAPs feature different combinations of 3.5mm SE, 2.5mm BAL, and 4.4mm BAL headphone outputs.  With all these choices you can go crazy keeping track of all your cables and terminations.  The solution is either to have multiple cables with different terminations or one cable with various adapters to go from 2.5mm BAL to 4.4mm BAL or to 3.5mm SE.  To simplify things, you can just get one cable with 2.5mm termination and a few adapters.

The adapters come in different shapes and forms.  There are short straight adapters, long straight adapters, right angled adapters, or pigtail adapters where you have 2 separate pieces connected by a cable.  With pigtail adapters it’s better to have a matching cable, but in general those are less bulky because a regular plug goes into the DAP socket.  Short adapters extend the original plug, making it longer, which can cause the connector to break if you are not careful.  Right angled adapters don’t stick out too much, making them the shortest.

DD team decided to re-invent the wheel of the right-angled adapter with a new design idea.  There is nothing that could be done to the actual male part of the plug (3.5mm or 4.4mm) which goes into the headphone socket.  But they moved 2.5mm female connector part to change it from right angled to T-shaped.  The only way it was made possible by using a flexible gold-plated printed wiring board (PWB) to save the room since you don’t need to use interconnect wires and to eliminate interference between wires next to each other.

The housing of the T-shaped connector part is fully transparent so you can clearly see the PWB.  For extra durability, stainless steel pieces are used around the edges, and the male part of the plug is gold-plated.  The adapters are very small and lightweight, where 2.5mm to 3.5mm (DJ33A) is only 2.5g and 9x13x8.5 (mm), and 2.5mm to 4.4mm (DJ44A) is only 3.5g and 16.5x13x8.5 (mm).  When used with a DAP, they look very compact, like it’s a part of the original cable plug.



Besides the original design of the adapter, the packaging of the product was very nice too, inside of a real wooden box with a shredded filling to keep adapter from sliding during the shipping.  But the MOST important part is that I compared these adapters to many of my other premium ones, and it sounds equally as good without any sound coloring.


While the title of this mini-review is “Audiophile fashion”, it’s clearly not only about the looks.  I was just curious to check out these DD accessories, and they turned out to be much better than I expected.  Been using the case and adapters every day, carrying my audio gear to work, and using 4.4mm adapter since many of my cables are still 2.5mm terminated and majority of DAPs have 4.4mm BAL output.  Bottom line, these are not accessories that just look good, these are accessories with high functionality that happen to look good!

3 thoughts on “DD HiFi Carrying case and 3.5mm/4.4mm adapters

  1. the 2.5 mm female balanced converter to 4.4mm male balanced, does it safe to use? will it harmful for dap nor iems? i check out pentaconn converter and they are super expensive, what a difference?
    im planning to buy it for balanced from sony zx300
    thanks in advanced


    1. why wouldn’t it be safe to use? that’s a purpose of this product and all other adapters, to convert from one connector type to the other 😉 Brand name products cost more money, and just like you have DAP under $1k and over $3k – there is a price difference in everything. Just remember, you can convert convert from balanced to balanced and from balanced to single ended. BUT never from singled to balanced.


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