HA3D : More uses than you would expect

This works great as a headphone amp. Balanced and unbalanced inputs, will drive most headphones to very loud level before distortion, good sound, dual power sources, and runs a long time on a couple of AA batteries.

In addition, I have found this useful for other purposes. Often I need to have a line level volume control, and this works great because of its multiple input and output connectors and battery power. It is also helpful when I need few dB of clean gain, or a way to go from a balanced to an unbalanced line. It adds no hum because it is battery powered.

One nit to pick: I wish the battery cover had a retainer so it's not so easily dropped or lost.

It's a well built and useful box that I would buy again.