"I know you and @mitch2 have Aric Audio amps and Hattor preamps"
@ozzy62 has Aric Audio amps but not me. I have a pair of 650wpc monoblocks made by SMc Audio using formerly McCormack DNA-1 amps as a starting point. Actually, I believe the only parts used from the DNA-1s were the chassis and heatsinks! Mine are the black pair at the bottom of the first grouping of pictures on the home page.
Although my custom built Khozmo volume controller is passive, I send the signal thorugh a unity gain buffer based on SMc's VRE-1 preamp circuit. My system is basically the opposite of Ozzy's system that uses high sensitivity speakers and tube amps.