Your single most significant purchase mistake?

@slovett At one point I owned a Proceed HPA 2 amp; I thought it was pretty good but it died at one point and needed to be serviced. The company repaired it at no charge, which I thought was great. As best as I can recall, I eventually sold that amp when I decided to explore the world of tubes. Th tube fascination lasted a number of years-

Technics PL-7 turntable… because I gave it to a Thrift Store… when I moved from Lewes,DE to Naples,FL

They also got ALL 200 of my vinyls collection… I am now 68… just can’t find either now

Paying a professional to create a digital room correction filter for me.  I figured out later that I needed to swap the position of my couch and my speakers (never have your listening chair in the center of the room if your speakers are against a wall).   It seems my system is too revealing - any digital attenuation comes at the cost of a palpable image, lower dynamics, less rhythm & pace.