Moukey Headphone Amp Amplifier 4 Channels Metal Stereo Audio Amplifier,Mini Headphone Splitter-4x Quarter Inch Balanced TRS Headphone Output and TRS Audio Input, DC5V Power Supply-MHAMP1

First impressions are very good. I initially encountered the low buzz / hum described in other reviews, but I've encountered this on various pieces of equipment with my setup, so I suspected I knew of a fix. I was right. I connected a Ground Loop Isolator inline with the input cable and it completely eliminated the hum. Others suggested using a separate USB power supply from the source device, in this case my computer. Using the included USB power supply and a cell phone battery brick both produced less hum than being powered from the computer, but in both cases it could still be heard when turning the gain up on low on no audio signal.With a ground loop isolator the hum was totally and COMPLETELY eliminated regardless of the 5v power source used. This is a very common problem with audio amplification, so I am not counting it against this device. In other devices an isolator will reduce, but not eliminate the noise, in this case it eliminated the noise entirely. Even without the isolator the hum was not noticeable with music turned up to a reasonable volume before being sent to the MouKey. So it's perfectly usable without it. I was able to push it to levels that were uncomfortably loud without clipping and I can't hear any noticeable degradation from the 16-bit DAC feeding it. As with many things, if you put garbage in you get garbage out. Feed this with a clean, strong signal and it performs admirably.This is technically an "amp", but I didn't buy it expecting it to significantly increase the volume relative to the source signal, that's what my DAC is for. What it does well is to split the signal and isolate the outputs so that they can be adjusted with an analog knob without impacting other outputs. In this it does it's job well even with headphones and mixers with different impedance levels and setting the outputs to vastly different levels. I could not hear any deviation in one output when another level was being adjusted.I haven't used it for long, so I can't speak to the longevity. But I accidently bought 2 of these and after trying one I'm keeping the other as a spare.

La tenemos en el estudio de grabacion, es un aparato perfecto para escuchar 4 audifonos simultaneamente buen material Recomendable

bought this headphone amplifier to power my DT 770 Pro, 80 ohms headphones and does a decent job. This is my first headphone amp so I cannot compare to the other more expensive ones. I have this amp plugged into my M-Audio headphone out jack. This amp has 4 x 1/4 inch OUT jacks. I have 2 of the jacks powering my Edifier and DT 770 Pro headphones. I have the other 2 jacks going to my sub-woofer. Everything works like a charm and my DT 770's can now get much louder than just plugging it directly into my M-Audio interface. This is a great little unit for a fraction of the cost of the more expensive ones. I like the fact that all the output jacks are on the rear of the unit and not in the front. All the wiring can be routed away from me which I like. There is a separate "master" volume knob which is great as I can turn down everything all at once and don't need to keep changing the individual volume knobs. Volume knobs have a good feel when turning. They don't feel "loose" or cheap. Case is all metal and has a bit of heft to it so it feels solid. My only minor issues is that the little volume indicator on the knobs are dark colored so you cannot easily see what level the knob is turned to and there is no power button. If you try to unplug the power from the unit, everything connected to it makes a loud popping sound i.e. my headphones and sub-woofer. I bought an inexpensive "micro usb power switch" to easily power on/off the unit but this still makes a loud pop when turning it on/off. Overall this was not a deal breaker considering this device was less than 30$. Very happy with purchase as there are not many headphone amps with multiple outputs and a separate "master volume" knob.

Mezcla sin ruido y no quita nada de calidad

Hab es mir gekauft um einmal meine Beyerdynamics zu betreiben zusammen mit meiner Anlage am PC.Kam sehr schnell an. Das Gehäuse ist aus Metal gemacht und macht ein allgemein stabiler Eindruck.Erfüllt sein zweck und macht es auch überraschend gut. Die Sound Qualität ist etwas besser als wenn ich es direkt am PC mit einen 3.5mm Anschluss anschließe, dazu rauscht es auch nicht und ist sehr klar.Musste nur 2x 3.5mm zu 6.35mm Kabel kaufen um mein PC als Output zu benutzten und für die Anlage anzuschließen. Funktioniert jedoch nur über meine Front Audio Eingänge die am Ausschalter platziert sind was etwas merkwürdig ist