Power amp for PSB Gold i's

The Gold i's drop below 3 ohms in the midbass region and present a fairly severe phase angle. They need an amp that is comfortable with difficult loads. The Classe CA-150 and Emotiva XPA-2 are both within your budget range. If you can increase your budget by another $200-$300, the Parasound Halo A21 is also within reach.

You're looking for an amp that doubles or almost doubles output as the load impedance is halved. The number of watts determines how loud you can listen. 200-300 watts into 4 ohms is not a bad figure.

How far from the back wall do you have the Gold i's ? If bass is a bit too much at times, try moving the speakers out from the wall a bit more.