I also thought I was getting good “slam” from the Coda until I swapped my Yamaha 2100 back into my system, and subsequently the Parasound A21. That experience really highlighted for me the power of expectation bias.
Apparently bass strength is a common sacrifice with amps employing little to zero global feedback.
However, I don’t think the OP would notice much, if any reduction in bass going to Coda from low power Pass Labs. The Coda 8 essentially sounded like a Pass XA25 in my system, just with more power and a little more bass extension.