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Fosi Audio MD3 in hand: Compact, lightweight DAC, convenient and noteworthy magnet suction

Bùi Đăng Minh•Wednesday, July 1, 2026•8 min read

Among the portable DACs I've used, I like this one because it's compact, light, and fits on the back of the iPhone. I use it for the Sennheiser IE 900 headset and put both in a small leather bag. That way it can be with you at any time and when listening to you, you can also operate the phone normally.

Small, light and neat is the most important thing

Currently, most DACs are big, heavy or not designed to be compact enough, fitting into the back of the iPhone to be convenient to hold and use like this Fosi Audio MD3. Fosi Audio MD3 weighs about 50g, considered one of the lightest DACs. So you can exploit it by holding the phone and listening to music at the same time. I use it with a very light iPhone Air, so the two items are just the size of a normal smartphone. However, if you use a larger and heavier device with a case, it may not be comfortable to hold. Because it is compact and lightweight, I can carry it comfortably in my backpack or accessory bag. Unlike other music players or DACs.

Both headphones, DAC, and USB cord are in this small bag. So it's very easy to carry.

Music playing ability:

Regarding the ability to play music, I think it can pull the Sennheiser IE 900 quite well and with its parameters, it can comfortably pull many small and light headphones that you have. Except for headphones that are too heavy, you need another DAC. In general, for mobile needs, I find it okay.

You will improve your listening experience a lot compared to listening to wireless headphones. Or other convenient solutions.

Other utilities you may or may not be interested in.

First of all, it has a screen so you can see the configuration of the music being played and the volume. Then that screen can also display the images you copy. In general, it's not very important, but it makes the whole thing look better. Then it has another USB-C port so you can power your iPhone while listening to music. I haven't measured it yet, but I see that the DAC in the Fosi Audio MD3 doesn't consume much electricity. So even when listening with an iPhone Air, it doesn't consume much power. However, having a power supply port is necessary.