I liked the Felix Echo but not quite

I spent some time with the Felix Echo OTL headphone amp recently. It's a fantastic amp especially for the price. It has a generous soundstage, amazing depth and tone. With my headphones, the Grado Hemps, I felt like the highs and lows were slightly rolled off and the overall presentation was a bit to creamy; smoothing over a lot of the detail.

So, can anyone recommend anything? I know the Echo runs about $6 or $700 but I'd prefer to keep it closer to $500 if possible. I'm curious about the new Schiit Jotunheim 2 but can't find much out there about it as it's pretty new.

Thanks in advance.