Damping factor

Hi folks,

Bass response question:

Does the damping factor (control?) of an amp have any effect on that of a dedicated subwoofer amp connected via variable line out? 

Or am I hearing something different?

My office system has a Hegel H 190 and a pair of Magnepan LRSs. The variable line out on the Hegel is connected to a dedicated subwoofer amp which powers 4 subwoofers.

I got back a Michael Yee Audio PA-1 SS 100wpc amp from Michael Yee sent in for repairs and some mods to the high end frequency response.

Over the holidays, I swapped out the Hegel and hooked up the PA-1 using a Bryston BP26 preamp. Variable line outs to the subwoofer amp. Same source (basic streaming from laptop)

After listening for just a few minutes, the first thing I heard was a noticeable difference in the bass response. 

At anything above low level listening, it seemed fuller and more enveloping. But not as tight (fast?). 

At anything above moderate levels, I had to get up and slightly reduce gain on the subwoofer amp.

Swapped the Hegel back in, listened for a few days then switched back to the Bryston/PA-1. 

Is this because the Hegel and PA-1 have very different damping factors that affect the subwoofer amp?

I tend to enjoy the difference depending on what's playing. 

Can't tell if there is an overall preference yet.

Just curious about what is behind this difference.

Thanks everyone!