People report hearing Adcom amps as harsh, edgy, etc. My experience was consistent with that. I'd guess you could best the Adcom for well less than 3k. For example, sticking to muscular SS designs, used Odyssey amps can be found at around 1k, and monoblocks with bells and whistles around 2k.
If you spent a grand on an amp, you'd have 2k to think about speakers (the component with the biggest impact on listening experience), and while I don't know your speakers, I'm betting 2k used can get you a noticable upgrade (esp. in this slow market).
But it looks like you enjoy tinkering, and since the Adcom is a likely culprit, I'd put my upgrade money in a more ambitious amp, and plan for a speaker upgrade down the road.
John