FiiOK5 Pro Headphone Amps Portable Desktop DAC and Amplifier 768K/32Bit and Native DSD512 for Home/PC 6.35mm Headphone Out/RCA Line-Out/Coaxial/Optical Inputs

Use with Sennheiser HD660S2. 300ohms.First set it up with blue tooth device direct from ipad.Volume was not very good. Full volume was not loud at all.I thought Fii0 wasnt strong enough. After lots of research, I figured out input wasnt strong enough.Fii0 can output 20 volts at 300 ohms, which is 1.33 watts. That is very loud on these headphones.I daisy chained a dayton audio DTA-120bt2 to the Fii0.I ran the DTA-120 on full volume.Boy what a difference. Could not go above 60% on the Fii0. No distortion. Period.I could hear the quality of the master. Excited about some, disappointed at others.Wish I were the engineer on some.I am going to have fun with my new headphone setup.This works well with high impedance headsets.Just make sure you have strong enough input.

I recommend it for just about anyone that is looking for a solid midrange budget dac/amp.Build quality feels good. The knob has a really good feel to it. You know that nice level of resistance so it doesn't get accidently spun but not to spungy to annoy you. The switches have a nice tactile feel to them so it's easy to tell which setting they are on and when they click between positions. Comes with all the cables (power and usb) you need along with headphone connector adaptor So you should be set if your 2.5 or 3.5. It also looks pretty clean. Easy to tuck away but not an eyesore on your desk if it's in the open.It also pushes my 150 ohm cans to perfection so I believe them when they say it can drive up to 300s. I have been fooled by other dac/amps in the past but that is not the case here. It drives what it says. Very clean sound. I do recommend getting the actually drivers from FiiO's website to get the best out of them on your PC though. It won't be as clean without them. So remember to do that if that is important to you. But if you just plug it in windows will detect it and you will have sound if you don't feel like messing with it (cannot confirm with an apple).But really does it all pretty well. Music, movies, and gaming are all satisfied to level you expect for the product. I know you will see a few cheaper ones and I would recommend you pass them up for this one. Its great. I believe to really get better you are going to have to almost double your budget and start to enter the realm of entry professional level equipment.

I consider myself a beginner audiophile. I just started getting into high-end audio equipment. This is my first purchase of a DAC/AMP. I do not do any professional audio work so I didn't really need anything too fancy.I mainly bought this to use for casual music listening with my high-end 80-ohm Beyerdynamic headphones. I currently have this hooked up to my desktop computer using an optical SPDIF cable. I do notice an improvement in sound quality with this amp compared to just having the headphones plugged directly into my PC. With the headphones connected directly connected to my PC they sounded somewhat muffled, but not with this amp.- The separation is better (sounds "wider")- It brings out more detail (I am able to hear sounds in the music that I never heard before).- The sound seems crisper and cleaner and there is noticeably less distortion- Better bass, more punch- headphones sound more equalized and better balanced.- louder soundThe only thing is that this does not seem to make much of a difference in sound when using the analog line in ports. Although I do love the flexibility of having all of the options available. It seems like the best way to benefit from this device is to use the SPDIF or USB input since they are digital (although I have not tested using USB yet).The only thing is that it cannot be powered from USB without using the AC power supply like other DACs, but that is not really that big of a deal to me since I will not be using this on the go. I will have it sitting on top of my PC tower all the time. This DAC isn't really made for portable use anyway due to its size.I would say I made a good choice with this purchase as it seems to suit my needs.