Purchase breaks well within 30 days


I purchased a $3750 dac used from a member and within a few weeks one of the two channels stopped working inexplicably.

The dac is under warranty but because the authorized repair shop recommends the entire dac board to be replaced it may take 4-6 month to get the part as the manufacturer is way behind because of covid and has limited capacity to manufacture things.  At minimum will be 3 months.

I would think
If repair estimated to be free and within 60 days or so the buyer should just be patient and not ask for refund.

But if a very lengthy repair timeline I am of the mind that a refund is appropriate but wanted input of others.

For sake of discussion lets assume seller had no idea there was problem and buyer did not contribute to problem

I'm surprised that the manufacturer hasn't stepped up and offered you a new replacement since the repair time of your unit is excessively long. It would certainly be a nice gesture on their part.
Say you purchased an expensive used vehicle from someone and the price included a free bumper to bumper warranty. A few weeks later the engine blows. Mechanic tells you you are to receive a brand new engine at no cost to you, but it will take some time. Would you demand that the guy who sold you the vehicle take it back, or would you be stoked about receiving a free brand new engine? It seems to me your gripe is you simply don’t want to wait so long to have it repaired.
If I bought a premium car would expect sale voided....if bought cheaper car different story. 

Premium product sold as premium deserves higher standard.

I would take car back fix it and sell it again or offer buyer premium discount for inconvenience.

BTW The dac manufacturer is low on new inventory due to covid so would not expect them to give me new one...
Was it made clear to you the sale did not offer a return policy of any kind?
You asked for our thoughts, but don't like the answers your getting.