IMG Stageline HPR-6

I bought this for someone who needs to compensate for hearing loss in one ear. The balance control combined with the adjustable (boostable) volume works perfectly in this regard. Being an active amplifier means even if the signal source is relative quiet -for example the headphone jack on a laptop, you can raise that volume and then balance it to taste. Usually, panning a signal to one side reduces the overall volume available, so this is a great help.