Tubeyist sounding Pre-amp?

You owe it to yourself to listen to CJ's highly acclaimed PFR SS preamp.  It is tube sounding without the issues of tube maintenance (magic how they do it).  Stereophile rated class A all the way.  If you can find one, you can get it at a good used price.  Based on what you are looking for I think it is a guaranteed love affair for you.  

" Do you 5 channels? Does anyone need 5 channels?"

If you speakers allow for it, you can use 4 of the 5 channels and do a vertical biamp. 

Thx - I see there was one on here but it sod.

My guess is that there is no magic, but a certain circuit topology and some MOSFETs involved....

The schiit saga is a new product $350 preamp. With your $500
budget it leaves some room to tube roll, although I’m not sure a single tube will deliver anything close to a fat sound.

my other suggestion would be a bottle head kit. 

A remarkable thread so much truth spoken. Agree strongly that most modern  tube pre amps sound is, fast, clean clear,  not rolled off or syrupy- unless you want them to be !  Cut to the chase, I recommend the AE-3 by a division of Cary.  They are no longer in production so buy used.  I did for less than $500.  They use the ubiquitous 6SN7 try a few brands of the old production tubes. Fair warning tube rolling can be addictive.  
I have no personal experience with Mapletree but have heard only good things about him.  They use octal but can be varied from the typical  assortment of audio tubes.