Looking to upgrade Adcom GFA555: Parasound?

The THD on that Parasound amp is pretty high for what it costs. Not that it will sound bad but based on my distant past experience with Adcom and Parasound and all other things being equal the Adcom you have is going to sound brighter and more refined. Things may have changed but Parasound was geared more toward theater than hifi. I would recap the Adcom before I spent $ on a new one that may not meet your expectations. If you decide a new one buy, I’d buy from someone that will take it back with no restocking fee just to be safe.

I don't know what products he is involved with or if any have been released yet, but Darren Meyers (engineer) is now with Parasound. He used to be with PS Audio and I would buy anything he designs without a second thought!

I really like the Parasounds, but they can be overly warm, maybe too warm for a background system?  You know what you might really like if you dont need lots of volume is a Rogue or CJ integrated instead.

I'm not a fan of Parasound.

Have you considered having the Adcom rebuilt and upgraded? The two techs that I'm familiar with who upgrade the GFA-555 are John Hillig at Musical Concepts and Chris Hoppe at Hoppe's Brain. Both are well respected and get great reviews/feedback.

Might be nice to keep the Adcom for nostalgia's sake, especially if the upgrades offer significant improvements in sound quality.

I have the Parasound A21 and absolutely like what I am hearing. Your amplifier seems a bit older. Hence I feel the upgrade to Parasound will feel like quite a big upgrade, especially if you are going to drive the Wilson’s. You might be able to find a used A21+ in your budget.

 For less than $5K you can get a used Parasound JC5. Do that.