I will give you my honest thoughts.
THis Cornet is a no frills unit, basic tubes, has the rca jacks in all the wrong places for many clean installs, and you spend more time boasting about the 'who gives a crap' power cord and bragging up the owner than describing the sonic virtues of the unit. The ad copy was a put-off to me.
I think a buyer that is knowledgeable about the Cornet will want a Cornet 2, and will not be willing to pay near as much for the original model.
Try re-writing your ad. If you gotta mention the power cord, just say it's upgraded. Lotsa guys (especially entry buyers) don't believe in power cord mumbo jumbo, so you lose credibility. Talk about the Cornets' virtues, post some good links to reviews, and don't prattle on about who the original owner is.
I watched the auction, and thought you should have let it go at $300 reserve.
Scott T