Best place to sell an amp.

What cal18 said +1, where-so-ever you decide to list.

IME, lots of low ballers and scammers on Craigslist. Had a $400 item, was offered $50. 
Also listed an expensive item and got a form letter response from a dealer... "we buy anything."

US Audiomart is free and I have very good interactions with members.

I agree, CL has a lot of 'Bottom Feeders'. 
 US Audiomart seems to have a lot too, at least from my perspective.

I have a super clean, very nice Rogue Audio Atlas Magnum tube amp with pictures listed over there for well over a year now.

I seem to get the same type of responses as I do from CL.

People low ball me, ask all kinds of questions, ask for additional pictures etc etc... knowing full well they really have no intention on following through with a purchase.

To some, it`s just a game.
 

"As for the past experience with the Audiogon buyer, he came to my office offered hundreds less then what I was selling the amp for, and just kept at me for every $5 increment. Nothing wrong with that really but it was annoying."

WHAT?!!!
First mistake is giving someone any personal information. That buyer was a fine example of a CREEP. I would have loved to tell a guy like that where to go with his money.People can be so....entitled and plain weird.

I've never had a problem here or AA. Be firm with your price,polite and say No If you're not getting what YOU want,wherever you do place your ad.