Fosi AudioFosi Audio K5 Pro DAC Amp Headphone Amplifier, Mini Hifi Stereo Digital-to-Analog Converter, USB Type-C/Coaxial/Optical to 3.5MM AUX/RCA Jack, for Gaming PS5/ PC/Active Speakers Up to 24 bit/192 kHz

This little amp is a quality product, it arrives well packaged in a smart box with simple instructions and a selection of leads. The leads themselves felt a little bit on the cheap side but perfectly good for the task, I suspect most audiophiles would buy their own leads anyway.The amp itself feels very solid, with an all metal case (no cheap plastic here) that has a nice satin finish, it isn't going to win any style awards with its functional looks, but still manages to convey a pleasing aesthetic that isn't going to look out of place in any setup.The amp was very easy to install and setup, literally plug and play on my PC with no fussy drivers to worry about. It all worked straight out of the box, and it worked very well indeed! The sound is great, with no noise and very clear highs and lows. My onboard sound is pretty decent on my MSI X470 Pro, but I would compare it to the difference between listening to an MP3 and then a FLAC of the same song. Like night and day!Overall this feels like a quality product that punches above its weight in all regards, I was so impressed I immediately bought another one for a family member who appreciates good audio. I don't think you can go wrong at this price point.

As a daily driver of the Fosi Q4 DAC (in combination with the BT30D amp) for my computer, and a BT20D for the bedroom it's safe to say I like Fosi gear. The K5 Pro is a fantastic upgrade and replacement for the Q4 in several aspects.1. Build quality and design: the new design of Fosi products has made the old black boxes look more sleek and modern. The gunmetal grey is stylish and works with any mini hifi setup or room. It just so happens to match the metal in my headphones and stand.2. Connectivity: the Q4 used a 5v micro usb for power, then a full-size usb type B to connect to a pc (the optical and coaxial are the same on both models). With the K5, one usb c is used for both power and signal. What impressed me is the lack of interference when using the same cable for both. Initially I was skeptical of this (without cutting the cable to see) but I can assume that there is a good degree of shielding of the individual cores to prevent any interference or cross talk.In addition the K5 Pro has added a 3.5mm microphone input next to the 3.5mm headphone output. This output can power headphones from 16 ohm to 300 ohm. This is a 100ohm improvement over the Q4 and as I have a pair of HD660s it makes a lot of difference.Just like the Q4 there is a RCA output to connect to speakers or a seperate amp unit.3. The DAC chip: the K5 Pro uses the new Texas Instruments NE5532 op-amp chip. Especially noticeable through headphones there is precise and punchy bass control and incredibly clear highs while never muddling the mids.4. Gaming: both the K5 and Q4 are advertised as gaming DACs. The K5 really improves over the Q4 because of the NE5532 chip. Using Dolby Atmos for headphones the positioning and soundstage was perfect for FPS gaming and immersion.I have only one gripe about the K5 Pro. It's the power button. To turn on and off you have to long press the volume knob. This means every time the K5 loses power you have to turn it back on manually. The Q4 had a point on the volume where as you turn the volume up the DAC turns on. Once left at a volume the Q4 just turns on and off without having to touch it. It is all down to my laziness but the quick press of the volume to change the input is a very nice to have.In summary the K5 is a clear upgrade over my Q4. Comparing my review to others they are saying similar things. If you just want something that sounds great and incredibly portable to power your headphones or to connect to your active speakers the K5 is a no brainer for the price. If you want the best of both worlds by using a pair of headphones and passive speakers like me the price is a steal and leaves plenty of budget for an amp.

I've been using this since I bought a pair of Hifiman he400 headphones and finding that my PC motherboard was impotent for driving decent headphones. For the price it is down the cheaper end of DAC amps but it's served me well.I've purely used optical input as I used to experience electrical background noise via other connections but it's been more than up to the job. The Sundara headphones I most recently purchased have found the limit of its ability but it is even still able to drive them to a very acceptable standard, I'm upgrading to see if they react better to a stronger source (as well as balanced output which I don't believe this unit can do).To be honest I would have been fine with the volume and quality as things stand, it's already able to hit levels that are not ideal for the ears and create bass as smooth and low as you could want at this price point.The point that goes against it hitting 5/5 is the volume knob which hits max at about 90% of it's rotation. More of a 4.5/5 but not worthy of full marks.Other than the sound side of things it's very well made, the knobs are a little cheap in feel and hard to see unless lit up with just one small detent on each so you can feel them stop at the 12 o'clock position isn't ideal but gives some feedback to go in blind with.I highly recommend this based on how it's performed for me, being able to run planar magnets is quite a plus point and the fact it's been turned on near enough 24/7 since April '23 has to be worthy of some credit.