Receiver for a 4 ohm speaker

Do you need the preamp/processor stage of a receiver?

I could recommend a few inexpensive amps that will happily push 100wpc into a 4ohm load, all day every day. You can pickup a Sonance 260 / Niles amp for under $100 used...

I purchased 4 ohm speakers (Dynaudio Focus 110) and was prepared to use my HK AVR 635 to power them after getting H/K's approval. I connected them and could tell immediately that the receiver was going to struggle to handle the load. I had an Adcom amp that I was able to immediately use to relieve the receiver of those duties and was amazed at the difference in sound quality. The receiver couldn't come close to the bass that the amp was able to produce. My point is that any of those receivers may be able to handle 4 ohm speakers, but consider an external amp to get the most out of them.

Many of today's receivers cannot handle low impedance speakers. I use Emotiva amps and they handle my four ohm speaker drivers effortlessly.

Generally, you're going to need to go the separates route to drive 4ohm speakers well...