Two defective pieces in a row - unreasonable to demand refund?

The most likely problem is an improperly seated connector inside the unit. It’s very likely that your dealer can locate this and correct it for you. Of course that doesn’t really answer your question.

Do you have a relationship with this dealer? You might want to consider that as part of deciding what to do next.

But to answer your question: Yes, strictly speaking, I think you’re entitled to a refund. So far, you haven’t received what you paid for. That the dealer has a "no refund" policy doesn’t matter. He hasn’t delivered.

Dump Mac and move on.

Bought 2 pairs of speakers and turntable from this dealer. This situation isn't the dealer's fault and I'd like to do business in the future. Don't know if demanding a refund will get me blacklisted from the store

Great opportunity to get out of an overloaded overpriced Mac and into a sweet high value Raven.

Is there any other equipment you're interested in at that shop?  They may not refund, but they may allow for store credit against another piece.

Can't hurt to ask, the worst they could say is no.