Is a convertible note a turn off to serious investors?
Yes, in the sense that if the investment is material in size (>=$1m), I won’t do notes.
More on why here: An Insider’s Guide to Convertible Debt vs. Equity
If the investment is <$500k in size, it’s fine to do notes, SAFEs, etc.
It’s not a “turn off”. Don’t worry about that. If you want me to invest > $1m, and you were planning to do all SAFEs or notes, I’ll just tell you that doesn’t work for me.