Hidden Gems in Pre-Owned Solid State Power Amplifiers?

The Killer B’s, Bedini, and BEL. Difficult to find them now performing to spec making honey nowadays. Most of them just like to buzzzz now.

The NAD Silverline series , Gryphon amp in a NAD chassis . Under $1000 on the used market 

Belles and McCormack with higher-level mods — beware the older models input boards are beginning to fail and need to be replaced.  I know this because I have one that needs a new board, and it’s an expensive repair. 

avanti1960

What are the true audiophile gems in the pre-owned solid state market?

Audio Research D-200, D-300.

@soix 
With SMc Audio's newer upgrades, they literally only use the chassis and heat sinks and virtually everything else, including the boards, is replaced.  Steve has my pair of DNA-1s that he is doing his "everything" upgrades to, including his new Gravity Base System that is supposed to make a substantial improvement.  I believe there are currently only a few amplifiers with this particular upgrade and I have read three owner testimonials, which are all very positive.  Mine will have new faceplates and should look and sound like substantially different/better amplifiers.