Your single most significant purchase mistake?

They did. Alberto told me they took it away because of Powell’s lack of customer service. 
 

That's good to hear.

i noticed the recently initiated thread on this mike powell fellow and his youtube posts were abruptly taken down... i had posted details of my unacceptable experience on that thread dealing with him

Biggest mistake, probably buying a fabulous Threshold T-200 power amp used and finding out it didn't mate with ML SL3 electrostats. It was twenty minutes of music and you stopped...had to sell it...still have the SL3s (in home theater now).

As a surprise, the Carver AV-705 multi-channel amp sounded much better than either my brother or I expected and he used it a while on Thiel 2.3s (late 90s). It was a steal, bought used.

Jeff Rowland Model 2.  Listened to it in the store.  Sounded much better than the Mac amp I currently had.  Brought it home, and it sounded much worse.  That was when I learned you needed to match the equipment to the room.  I still remember my wife telling me to get the old amp back in the system.