Has anyone sold over $35k worth of equipment over the net? How do you protect yourself?

You can't protect yourself.

What you can do is ensure that whatever you are doing is done to safeguard yourself as a seller.

Do not let yourself be bullied into a persons buying pitch, there are 100's of long winded get under your skin techniques. 

Do not sell anywhere that a Buyer Protection is a enforced method for the Buyer to make a Payment.

Typically a few Months can lapse before the use of the protection can kick in.

It is very important to have a sale with the residual overhang and menacing that can be brought into the sale.

@jmnextime1 - Indeed; I would never buy anything if my only option was wire transfer; I could be mistaken, but I'd wager the buyer gets ripped off more often, as the unscrupulous seller has the item (or it doesn't exist) and the buyer has nothing until they receive it, and no recourse if they don't. But common sense works on both sides. 

I put stuff on Face Book,local  and cash.I worked for the old PO loading and unloading trucks I've seen in person ,packages being thrown  and mishandled. I worked as a shipping clerk for a,audio and electronics company...seen stuff packed poorly. I Worked for UPS as a tracing clerk and then claims dept...I've seen it all ,all kinds of fraud,and lousy claims,liars and thieves.Ifs not easy selling audio equipment Good  Luck 

Perhaps I am just paranoid. But no way I would ever do something like that. I would sell to a reseller or consign. Ever since I got ripped off as an 18 year old buying a used car, where the battery was charged to cover up it had no alternate, or fly wheel and could only operate for a few hours. The guys were at the bank cashing the check immediately. 

I also know guys that buy and sell $10K audio stuff. They seem really lucky to me.