Need advice on what amp to get under a budget.

My dad has been using a Carver Receiver (MXR 2000) to power Polk Audio SDA Signature Reference Series 2 Speakers since he bought them in the 80s. The receiver has started to turn off and on and switch sources on its own, and has also produced a ringing sound constantly when turned on. I don't want to continue using it until it's fixed, but me and my dad are both thinking that it's time to replace the Carver with a newer amplifier. We are looking for something under $1000 if possible. I don't think we need anything above that, and the room is quite small so we're both not concerned with massive power, we just want good quality. A friend suggested NAD. Are there any brands or specific models that are well known for their high quality under $1000?