DS2 USB C to AUX Headphone Amp DAC Dongle 3.5mm Jack Audio Portable Amplifier Dual Output DSD256 4.4mm Balanced High Resolution CS43131 for iPhone 15 Pro Max Plus iPad Android Phone

---Update--- Fosi has been communicating with me and been very helpful to solve this issue. They are so nice to deal with and glad to have your business and I'm glad to give them mine. They must have the smartest tech support too to be able get through to me the things they have been able to when I've asked them for help. And they have a lot of very great electronics that most of us can't get enough of! :) ---Original--- I bought a new item and label on box says new too but the round tape that was trying to seal it closed(see picture) was barely left with any adhesive left in it and full of lint as if it had already been opened and tried to be resealed and returned for resale or to be refurbished so I opened it and while opening it it made so much noise from everything loose inside. But I did not buy a used or refurbished item that this appears to be, nothing inside was in place. I figured as long as I had it I might as well give it a listen, so I did. I have many Sabre DAC chip equipped pieces whether in phones or dedicated DAC/amps and most recently a dongle from HiBy, an FC4 and I thought this would be a nice change getting away from ESS chips and give Cirrus chips a go, I couldn't be more surprised when A/B testing them(from memory((from side by side))) that are so very similar. I don't possess the words to describe how minimal the differences there are between the 2 chips are when used in these 2 applications, it is really amazing. I was expecting a lighter, relaxed, atmospheric, type of performance from the DS2 but it is every bit as analytical as the HiBy and Sabre chips. Still worth having both to me by the way, due to power gains had in the Fosi DS2. You wouldn't guess there were gains in power made in by the DS2 until it's about half way turned up then it's just thick and loud sound. Beautiful, thick and loud. I don't quite know how adjustability is done on the DS2, I think instructions suggest downloading the HiBy music player app which in all fairness has very many types of adjustments DACs it's just that the player itself seems to be causing a lit of problems for me, so I'd use it for adjustments and go back to your normal player for your music and and streamer once done with adjustments. That's just what I've found to be best for adjustability on HiBy and may not be true of Fosi. Oh also, the HiBy player tries to load twice when I plug in my USB dongle, so I uninstall the player until I want adjustments. Crazy but true. Lol Anyway, I can't say enough good things about this Fosi DS2, I wish it shipped looking like it was actually new and left me not questioning, but it sure seems like a high performance, very high quality, very great value. Performing equal to many above it's weight class and caliber. I'm so surprised it sounds nearly identical to the Sabre DAC chips that I'm used to, I've read so much about Cirrus and thought I knew what I was getting into. I pleased with the sound and will keep the DS2 as part of my setup due it's power alone and clean power at that. And Fosi is now a part of my future equipment too! This really impressed me. I hope I've been helpful, Thank you.

The Fosi Audio DS2 pairs perfectly with my CrinEar Daybreak Triplicate-Hybrid in-ear headphones. Audio is clear, detailed, and has plenty of power to drive them without distortion. I’ve tested it on Windows, macOS, iPhone, and iPad, and it works flawlessly on all of them. It’s compact, well built, and easy to take anywhere. For the price, the sound quality and performance are hard to beat. If you’re looking for a solid DAC/amp for quality IEMs, this one delivers exactly what you need.

I've used this little Fosi DAC/Amp at the gym daily 5-6 days a week for 2 hours a day for weeks. Below is a quick pro/con summary and the associated gear I used with the Fosi. I then delve into my impressions of this slick little device plus a comparison with the higher priced and highly adjustable Qudelix 5K DAC/Amp with an internal rechargeable battery. What I like about the Fosi: pocket friendly well built intuitive simple and inexpensive solid upgrade for properly fitted IEM use in noisy environments. What I don't like (and why I knocked off one star): the Fosi is a power hog on a new iPhone cheesy USB C to USB C cable needs immediate replacement The IEM gear I used with the Fosi (I keep my IEM's in Pelican cases for protection, they are NOT stock): Ziigaat Odyssey IEM Moondrop Dusk IEM (Crinacle) 7HZ Timeless IEM iPhone 16 pro - new as of 4/25 Tidal streaming app for iPhone Thunderbolt 5 Cable high Speed 80Gbps Data Transfer,16K/8K/4K type c to type c The little Fosi adds depth, bass, timbre and soundstage to all 3 of the aforementioned IEM's which are all considered best in class for the price on the Hangout Audio website curated by the wizard of IEM's "Crin" or "Crinacle" aka Corin Kohn. I used the Fosi and interchanged my various IEM's at the gym every day which may appear initially to some as a loud and semi-absurd place to review IEM's and small DAC/Amp. In reality, it's ideal because noisy gym replicates the worst of the real world and puts IEM's, the ear bud tip choice and a DAC/Amp to a strong acid test. The Fosi passes for its low price point, dynamics and simple connections which are USB C to USB C in my case, and I bought a top-quality aftermarket USB C to USB C cable because the included cable is chintzy. One key here about ear bud tips - cheap, ill-fitting ear bud tips can make even a top rate DAC/Amp sound bass free, with thin mid-range and a tinny high end so get good quality proper fitting tips before you blame the Fosi or other DAC/Amp for garbage sound. Be aware of two simple facts about the Fosi. Fact one is that it uses source battery power (iPhone battery in my case) and it has volume buttons +/- that act independently of the iPhone volume buttons. The Fosi power drain is significant. 2 hours of Fosi use with my nearly new iPhone 16 pro drains the battery from 100% to about 84%. When using just an IEM for 2 hours, I get a 4% power loss from running Tidal and negligible power loss when using a Qudelix 5K DAC/Amp that has a rechargeable onboard battery. The Fosi onboard volume buttons sound like a silly thing to talk about but you can have your iPhone volume wide open and the Fosi volume set very low and get terrible Fosi performance. Adjust both the Fosi and source volume appropriately. I show a couple of photos of the Fosi next the slightly larger Qudelix 5K DAC/Amp. The Qudelix is about $100 on sale on Amazon but it's next level for total audio control because it includes a 10 and 20 step equalizer, a terrific app and a mind-boggling amount of audio adjustability for any headphone or IEM. The Qudelix allows for wildly expansive audio tweaking but it's complex and the Fosi is simple. If you want plug and play, get the Fosi, if you want total mastery of your head related audio and are highly audio tech savvy, buy the Qudelix 5K. I hope this data helps you make the best in this category for your own needs.

Fosi Audio DS2 USB C to AUX Headphone Amp DAC Dongle 3.5mm Jack Audio Portable Amplifier Dual Output DSD256 4.4mm Balanced High Resolution CS43131 for iPhone 15 Pro Max Plus iPad Android Phone I originally got this for my Mac Studio, but it’s become the glue that connects all my gear. I have a pretty extensive collection, including the Sennheiser HD 490 Pro, HD 660S2, and the FiiO FT1. If you have high-end headphones, use the 4.4mm balanced port. On the 300-ohm 660S2s, the difference is massive. On the standard 3.5mm jack, they sound a bit thin, but the balanced port wakes them up with deep, rich bass and way more detail. It makes my acoustic and classical tracks sound incredible. I use the Sony XM-6 as a wireless headset and plug them in via 3.5mm when the battery runs low or through the DS2 and it tightens everything up. It’s way clearer than using Bluetooth and uses no power. It works with my PS 5 Pro too. You just plug it into the front USB-C port and it works. It’s a night-and-day difference compared to plugging into the controller. Everything from footsteps to cinematic scores sounds more real and immersive. This thing is tiny enough that I just toss it in my pocket with my Apple iPhone 17 Air or Samsung Fold 7. It doesn't drain the battery much, but it gives my mobile listening that desktop quality feel. At home I have a collection of DAC's, pre-pros, and receivers including an SMSL D100, a Denon 4800, an Integra 5.4, and an Emotiva XMC-2. Those are all great for my room speakers, but for headphones, I actually prefer the DS2. It’s quieter, more intimate, and that 4.4mm output is honestly better than the standard headphone jacks on most of those expensive receivers. Fosi nailed it again. It’s reliable, powerful, and sounds amazing. Whether you’re a beginner or have a house full of gear like me, this is a must-have. This is the 5th product I’ve bought from Fosi Audio. I’ve even started giving this specific product as a gift to friends and family because it’s just such a simple, high-impact upgrade for anyone who likes music. There's an in-depth review at Audio Science Review that goes into more details but this product is recommended.

I had been enjoying high quality flac files on a DAP with my iEMs lately. But Spotify on my phone with my IEMs through this DAC is pretty darned enjoyable as well. Heck, I don't think I'd be able to really spot the difference in an A/B test. Great product. Makes me kinda regret buying a much more expensive and muuuch heavier and larger portable DAC last year. But in my own defense, I sort of needed the power since my headphones are higher resistance. Live n learn. Happy listening! The noise floor is low. Silent is dead silent at my listening levels. And the volume control is great. Especially relative to the super coarse volume controls on iOS. This is easy to recommend.

I am not using this in a mobile fashion. I use a USB-A male plug to USB-C male plug converter cord. That's not been a problem. Caveat: I am old and have old ears, I'm always adding a semi-scooped EQ. No, I don't use any fancy music player applications, I am old skool and cling to Windows Media Player. THE BAD: This DAC * hated * my Symphonized Wraith dynamic headphones (an older brand, model from 5 years back, that normally performs fine for me). THE MOSTLY GOOD: Things got a lot better when I attached my Sennheiser HD595 (open back, 50 ohm, dynamic headphones). This DAC headphone combo: It's neutral, not rich. LOADS OF AVAILABLE VOLUME. My old ears want more shimmer in the highs, and un-EQ'd the midrange is somehow "blocky" BUT, THAT'S JUST ME! YMMV. Just saying. What this DAC did for me: It immediately widened the scope / choice of headphones I could attach to my PC for relatively little money ($59.00). Before I purchased the Fosi DS2, what my downstairs PC had going for audio was just a $39.00 Logitech work type headset with mic that had its own DAC in it. Using that older $39.00 headset with internal DAC was marginal for music. My MSI motherboard is 10 years old. So, YEAH, the FOSI DS2 IS a jailbreak solution if your PC has an older / substandard onboard DAC. I'm on the honeymoon and for some reason am not completely thrilled with it, again, I want those elegant shimmering highs. Midrange is - to my ears a bit constrained - It could be my particular Sennheiser headphones paired with this DAC. BOTTOM LINE (FOR ME): It lacks wholeness or pizzaz. nebulous words but there it is. It may grow on me. I seem to recall liking my older Topping DAC that got retired better. It may be I have to upgrade my headset, but, that's never been a driving issue before this. If I take these headphones upstairs and put them on my 3 year old HP laptop's audio jack or put the Sennheisers on my new M3 iPad, it sounds pretty good. So, take this info as you will. Again, it's the honeymoon.

Wow, really great. doesnt add coloration and has a little umph. I have this paired with Shure 840a and it is a great combination. Quality is very high, performance is high, cost is kept in check. Highly recommend this combo if you want something dip your toes into the higher end of audio but do not know if it is worth it or not. This will give you a great taste - for reference I mean natural tonality. I also use this on my IEM, which is a better fit for this dongle and it sounds great. The balanced output does actually add a little quality and umph if you do critical listening and comparing but it is not night and day by any means.

I do not recommend this product at all. We tried it with Sennheiser HD 650s and I spoke with support and they said that this item can't power headphones like that. Sennheiser HD 650s are excellent products but certainly they're not at the same tier as those costing thousands of dollars more. Is speaking with support they said that it's the product and it just can't power enough. I spoke with support on WhatsApp per their request