Fosi AudioDS2 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

Works great on my Pixel 9 Pro XL to drive Audio-Technica ATH-R70x reference headphones (with balanced cables) which have very high impedance (470 ohm), requiring more voltage to drive. This impedance is slightly above the specifications that this DAC is rated for (16-300) but it is still able to provide good volume with fantastic clarity. I also tested with Dan Clark Audio Noire X (with unbalanced cables) which is slightly lower impedance than this DAC is rated (13 ohm) and it still performed excellent, however volume needed to be closer to the top of the range on both source and the DAC. This DAC did not have noticeable power draw or heat when driving the ATH-R70x, but it definitely warms up slightly with the Noire X. The build quality feels premium, though I wish it had some kind of volume level indication. Overall, the Fosi Audio DS2 is a fantastic value in a highly portable package, capable of driving a wide range of headphones with excellent fidelity.

---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. LolAnyway, 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.

Great sound, dead silent, balanced audio output. If anything, my only complaint is that it can't achieve dangerous volume levels on my 300Ω Sennheiser HDxx headphones.It's USB powered, so it'll use the battery from your phone or portable device if that's what you're plugged into. The louder it is, the shorter the battery life. Still: I had it at a reasonable level (~75 dB or so) and it lasted hours while barely denting my iPhone's battery)It can get a little toasty during operation, but it's not too hot to touch or hold. It's built well, looks solid & sleek.It works great with my iPhones, MacBooks, and Linux desktop machines. With that kind of compatibility, I imagine it'll work well on just about anything.

The unit looks / feels nice and works well. The type C cable that came with it feels very nice to the touch and appears to be good quality, but was dead on arrival. The cable does not work at all with my phone (S24+) and when plugged into other devices only drove one speaker and generated random static while playing. I am currently using a standard samsung cable and the dac itself works great.Uses:Headphones: work great as intended with all headphones testes (I don't have any particularly difficult to drive to test them on. I mainly use them with sennheiser hd569's)Stereo systems: sound is clearer with defined instruments sounds. It appears to lesson some of the bass response from my mini system (fosi bt20 pro into some old Kenwood speakers with dual subs) but it might just be more controlled, I just prefer more bass with that setup. It soumds great through an old Phillips receiver powering some old mission bookshelves. (Although I actually had to turn the treble down with that system for for the first time ever with that setup)Car audio: it sounds great and is noticeably much louder. (I had trouble getting to even audible volumes while plugged into my factory Aux port.)Rating: almost 4 stars.. would give 4.5 stars if cable provided worked (and if possible) Great headphone amp / dac

Sounds excellent with my Sony Xperia 1 V 256/512 and the Sony MDR-1AM2 wired headphones. My regular phone is a LG v60 which has built-in 32bit DAC only with wired headphones. I purchased the Sony phone has a Xmas toy for myself on sale. This DAC greatly improved the sound and volume of the Sony. In fact to my ears the sound with volume control is louder than the LG v60 and just as clean and clear. All at compact and neat package. Everything was included in the box get going. When I plugged the device into the phone Sony did a quick software update and I was off and listening. I'm a happy camper now. I wish Sony Xperia 1 V came with a built in DAC/headphone amp but this is low cost substitute. I'm very happy...