I'm using Pass XA-160.8s with modified VSMs. I previously drove the VSMs with a modified BAT VK-75SE. Both amps (and the XA-30.8s) have ample power for Merlins. The Pass amps are eerily quiet and smooth on top. Relative to the tube amp, you may initially perceive this as a loss of HF extension and air. But I think the Pass sound is more faithful to source. Try them with and without the Merlin Zobel-- you may not need it.
