Best Class A amp with SLAM

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...ditto what Map said.
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Maybe I should have kept them and had them recapped. They were almost 25 years old and it was time for a change. As far as speakers go, I have Wilson Maxx II's and am amazed each and everytime I listen to them. As far as amps go, the Pass Labs are smoother and I'm not in to only slam, but I do miss that attribute of the Krells. My X100.5's will suffice for now. They're great amps. As I said, perhaps I'm remembering the Krell's through rose textured ears.

You should add to your audition list the Electrocompaniet AW series monoblocks: AW180, AW400 and AW600 (Nemo)

Smooth sound and can handle loads down to .5 ohms.

I also own the Pass XA.5 series, and although I love mine, it seems that these amps are a bit reticent in the bass/slam department. I've read that enough times from enough different people that I'm pretty comfortable attributing the issue to the amps.

Most slam?

Probably the biggest, heaviest, highest wattage, power gulping, least green, most expensive one out there, whatever that is?

I could have used a pair like that with my large OHM 5 speakers.

But not practical for me (or most) so I tried Class D and have not looked back.