Ask HN: Can you pay down a YC SAFE like a debt note?

Short answer, no, a SAFE is not a debt instrument.

Long answer, see: http://www.ycombinator.com/docs/SAFE_Primer.docx

I think the more interesting question is, do you have to register under an SEC exemption to sell SAFEs? I'm going to say yes, I'm sure the SEC would considered this covered by the regs. I think that's the next hurdle to make financing a LOT easier.