finally hooked my PPX3 Slam back into my rig. I was pleased to find my 999es has two outputs that both work simultaneously, so I was able to do a quick A/B by turning both the Melos and Slam on, and frantically pulling and replugging in my cans. CD used was the current remaster of Peter Gabriel's third album.
With the HP2: In short, the Slam had more, well, slam, while the Melos had an overall smoother presentation across the entire range. The Slam does not put enough emphasis on the mids and lower-highs for my taste, going instead for midbass impact. The Melos wins with the HP2.
With the RS-1: I have NOT been impressed with the Melos + RS-1 combination, at least relative to the Slam, which I suppose better suits the RS-1s "rockin" sound signature. That midbass impact is crucial for the RS-1s, at least that is what I'm looking for when I pick them up. Amongst other things, what this tells me is there really is a drastic difference between the Joe Grado and John Grado sound, though both have their similarities, namely small soundstage and smooth midrange, which I guess is the Grado house sound.
With Senns: The Melos leaves much to be desired with Senns. Actually it leaves everything to be desired. This is no surprise, the PPX3 wins hands down.
So am I saying I think the Melos is a one can amp? Maybe. I'll give it a shot with my MS2i, if I ever get it . But if it is a one can amp, it does a fine job with the one can it amps for.
Also still waiting on my Dynahi, looking forward to seeing if a solid state can compete with the tube and tube hybrid crew.