Behringer Powerplay Pro HA4400 : la opinión de peepsaudio (content in English)
I got this headphone amp a couple years ago. I just wanted something simple to pump up the headphone levels I could get. My drummer was having a hard time hearing his headphone mix above his drums, and my sound card just didn't provide enough power to get it above the drums. So I picked this thing up, and to that end, it works great. It's not without its problems though. It definitely changes the sound of whatever you put through it, and not in a good way. Everything sounds kind of tinny and somehow fake on the other side of this amp. I am pretty sure they use low quality power amps that are very noisy. The signal you get on the other side has a much higher noise floor than what goes into it. Apart from this, it is conveniently sized at 1 rack unit, and has individual volume and mute controls for each of the 4 headphone channels it gives you. Though the signal is kind of dirty, you can get it very loud. In my case, that's really all I was looking for, so I let the signal degradation slide. The amp also gets very hot, so you'll want to give it an open space on either side in your rack for it be able to cool off without damaging other nearby racked equipment. It has worked very reliably, and none of the parts have worn out on me since I've had it. This is probably one of the cheapest 4 channel headphone amps you can buy, and if you are not really concerned with pristine audio quality for your monitoring and you just want loud headphones, it's a good value and will work well for you. If you want everything in your signal chain crystal clear at all times, this isn't the product for you. I would get it again, it works fine for me.