This amp sounds great. I would recommend it.

The volume knob is continuously variable, but it does have close-spaced stops around its range. When the input levels are high (as from iTunes on high-fidelity output) the listenable range is crammed towards the low end of the dial, and more often than not, the ideal volume lies between the stops. It's not a huge problem, as you *can* get there, but it takes more care.

The amp also outputs a strange sort of popping-squeal when you turn it on, so it's best to turn it on *before* putting on headphones.

Update: After about half a year, one of the blue under-lights stopped working. This has no impact on the sound, of course, but it's a bit disappointing.

I typically use my phone to listen to music. I am a Spotify subscriber and listen to music at "extreme quality".

My everyday headphones are Senheiser Urbanite XLs. My phone, an LG V10, has a built in 32 bit DAC and it sounded pretty good, however I was looking for something to add some more life to my music and figured I'd dip toes into the headphone amp market. At this price point, the Nobsound was a great place to start.

This is a nice little amp. Yes, it is a hybrid (tube preamp, with solid state amplification). Purest will say an amp like this is a scam as it only uses the tubes in the preamp stage. I think this gives the end user the best of both worlds.

What the tubes do is add a bit of warmth, and to my ears, this amp adds a wider, fuller sound stage. Rock sounds clean and crisp, EDM/dance/hip hop have nice bass.

It has adequate power and easily drives my headphones which don't have the highest impedance. Bass is rich and full. Highs don't "sparkle" which is good as they don't "fatigue" my ears.

The unit is solidly constructed with a metal chassis. It has a step volume control (you can feel a 'click' on each turn). The tubes, with the blue LED under them, are just plain sexy.

As the 9 pin tubes are replaceable one can "tube roll" (i.e., use different tubes) to change the timbre and tonal qualities of the sound. Tubes can be found on the cheap (I've found tubes under 3 bucks) and this creates a fun way to experiment with your sound.

The unit is small and is a cool addition to my standing work station.

I spent a good hour listening to a Spotify playlist to test one's headphones. It is a varied playlist from rock, ambient, instrumental, etc. Of course, I'm listening on good headphones which makes a difference, but this little amp made them shine. Bass was deep and clear, miss were sharp with muddiness, highs were bright but not to the point of being harsh. I was completely impressed.

If you are a "budget audiophile" then this may be the ticket to drive your higher impedance headphones.

Bottom line: solid construction, cool retro aesthetic, and great sound at an affordable price.

I would recommend this product!

This is advertised as an integrated amp, but I haven't tried it yet with a line level source. It works well with a pair of Sony 25 ohm headphone connected to my iPhone 7. The phone's headphone amp is about what you'd expect from a phone, and this inexpensive accessory is a major improvement. I realize that the quality of the sound is limited by the signal from the phone, but I still enjoy the bigger sound from this little amp.
It works bigly- D. Trump.

I bought this amp to go with my Bayerdynamic DT880 cans. The improvement in sound with just the DT 880's is phenomenal, but with this amp I'm blown away. I can't listen to music without it.

With the DT 880 I hear amazing detail in music I've known for years and hear things I've never heard before. But once I add the amp I hear better mids and richer bass. The best way to describe this amp is it's like going into the room where the musicians are playing only with better acoustics. It's the difference between a dead room and a symphony hall - you hear everything! The room comes to life.

I highly recommend this amp and can't wait to hear what better tubes will do to improve the soundstage. Must buy!

I cannot believe the difference this 50 dollar amp made. Using it with my Samsung tablet or my pc headphone output
with my Grado SR80's blew me away. I just kept wanting to listen to more music, replay everything in my music files.
The Grado phones are great to begin with and this amp made them shine even more. The bass became tighter and much more immediate
as well as the sound of the drumstick bouncing off the cymbals, even a wider soundstage on music I was very familar with. I would
recommend this to anyone who has a decent pair of phones and wants to get that little extra aliveness from their music files.
Best 50 bucks I've spent on my system ever!