Update: got the PS-2a yesterday. I used it with my Splawn Comp. Easy to set up and dial in. I was comparing using the PS to attenuate the Splawn vs. the Splawns Loop Master/Return volume on the back.
I give the Edge to the PS-2a for sure. The two toggles for Bright and Warm have a substantial impact over the tone and punch depending on the Volume level of the PS-2a.
I set the Splawn to 9:00 and 10:00, which are the ideal volumes for that amp.
It did confirm for me that I might be able to get the same effect using the Splawn's Loop Master Volume and an eq pedal in the loop, to match the tone and feel of the PS-2a attenuating the amp. But the PS-2a is difinitely the winner overall.
I want to try it with my Hellion next. ...I could see that I may not need the PS-2a to attenuate my MV amps that have preamp driven circuits, BUT, I could see it being very handy to give more power to lower wattage amps and modelers.