HP4 : Useful, not perfect.

Chosen specifically to provide power for multiple headphone mixes from pro tools outputs. This task is one it completes with ease. 4 channels of output, each with a selector to choose from the 4 channels of input. This is an extremely useful and versatile unit even for its flaws... It goes LOUD. Beware! However, on occasion it has been liable to distortion at low levels, on all or just some input and output channels. I feel that this is a far better unit overall, when compared to the Behringer HA400 which is probably the closest comparison at both features and price. Were it to break down or be stolen, I would either buy the same again, or save up for the Presonus HP60 which is IMO the top top headphone amp.