"I personally have multiple headphone amps including original Phonitor, Phonitor xe, RME ADI-2 Pro, Lynx Hilo, Prism Callia, Rupert Neve RNHP Headphone amp, and Cobalt Dragonfly. I can confidently say that the Little Labs Headphone amp (connected to RME ADI-2 Pro dac via XLR Mogami cables) sounds amazing. Construction and attention to detail are top notch. Extremely well made high quality amp. This is professional pro audio equipment with additional useful features not found in other pro audio amps. Detail, clarity, resolution, transparency, and soundstage are as good if not better than my other amps. This is a very resolving amp. Great detail in the low end. I’m able to hear details in music I’m very familiar with that I didn’t hear before. No “color” added. Plenty of power to drive high impedance headphones such as the 600 ohm Beyerdynamic T1 (first gen). I am not able to hear any music leak when volume turned all the way down to zero as mentioned by other reviewer. Was this other reviewer’s unit defective? Also right and left balance is spot on. Inaudible noise perceived. None. No distortion of music at high volumes. Frankly for the price and quality of components and linear power supply, this unit is a great value. I am very happy and impressed with the purchase of this unit. Little Labs hit it out of the park with this amp."

"The sound is incredibly good and the features are very well thought out. The killer feature in my opinion is the recessed buttons that allow the Monotor's volume pot to be disabled, allowing level to be controlled by the audio interface. Even if you're used to a quality interface, you'll probably hear detail that you were previously missing."

"I have UA Apollo and RME UFX+. There is no substantial difference between those and a $540 dedicated audiophile unit. Save your money and buy other equipment. It could be an improvement if you own behringer or other cheap stuff or if you using smartphone ;) If you have a decent focusrite or audient there is no need to pay extra for this. On top of that when the volume is set to zero (all the way) you can still hear the music. Apparently after contacting little labs they said it is normal. I am sorry to say that but even 10 times cheaper amps mute headphones completely. With this you have to unplug power cord or disconnect the source... disaster"