AKG HP4E 4-Ch Headphone Amplifier

I use AKG HP-4E to drive my HD650, and it works pretty well.

Okay for low ohm cans like 7506's, but hook up a pair of 250 ohm cans (DT 880 Pro for example) and volume is woefully lacking.

Got this to pair with my mixer/interface so that all artists recording can hear the mix through their own headphones instead of using speakers. Does this job very well. I also use this to host small listening parties and to test headphones side by side without the need for constantly plugging and unplugging.For these latter cases, I use an ODAC as the input.Pros:- lots of ports for headphones with 1.4" and 3.5mm endings (8 in total, 4 1/4", 4 3.5mm)- A & B input switcher- can get very loud but your mileage may vary based on headphones and their impedances- very forward sounding; good for recording with different instrumentsCons:- no rubber feet. When I first got it, it would not stay put since its bottom is flat with no grip. Had to place my own nonstick feet.- no power switch- blue power light is very bright. I stuck on a piece of electrician's tape because it's very piercing in dark rooms- not neutral- inputs clash and bleed into each other (i.e. when something is playing through input A, you can hear it a bit if you've selected input B on the amp and vice versa)- not the cleanest sounding amp (lots of noise when volume is turned up)

This headphone amp is wonderful. Perfectly powers the AKG K712. Full metal case, excellent quality and sound. Perfect.

Absolutely fantastic piece of gear, I wish AKG would make this more widely available.Its got the capability or recieving 2 alternate mixes via its a/b inputs, for a recording environment. I searched hi and low and couldnt find other pieces that do exactly that. In recording often we want to feed alternate mixes to musicians who are playing live. this is the piece to do that.

Bought this on recommendations that smaller, portable headphone amps wouldn't drive my Beyerdynamic DT 990 Premiums (250 ohms). Had previous tried both Mackie and ProSonus with no luck (volume was barely adequate, no headroom). This is a well built unit with some really nice features for the price (dual headphone inputs, A/B switch, individual volume settings) but after a few weeks I started noticing I always had my guitar, amplifier, and the volume on this unit turned to Max to get any kind of strong volume.If you've got an ~80 ohm amp and want some boost, this work fine, but for my application anyway, it came up short - even a portable, battery powered headphone amp drives my headphones better than this one seems to. Plus, as many others have pointed out, it's lame that a $100 item doesn't even have a power switch.

Excellent value for the money. Using it in our podcast. Works great.

I don't think that there's anything particularly wrong with this little amp, but I was hoping for more power. The headphones I'm using are AKG K7's. As it's set up now, I have my record player (with the pre-amp turned on) plugged into Input A, and my phone (with built in dac-amp) plugged into Input B. The record player sounds just fine, no complaints really. But when I'm listening to my phone through the HP4E, it degrades the sounds and it sounds much quieter.At the end of the day I was hoping to boost the sound, not degrade it.