No, not a "metal-face Plexi"... after all, that's a contradiction, right?... This is just an observation I've tested time after time, on every "plexi" style amp I've ever played. Now that I finally HAVE one (a JTM45/100 clone,... close enough to reasonably say you "have a plexi," unless you're trying to sell it,) I've been able to fool with it enough to confirm that this is true: You can get a "metal" tone from a Plexi-style amp by doing this one thing: only playing through Channel I (the "high treble" channel,) and turning it literally UP TO 10; or, if the channels are jumpered, turn Channel I up to 10 and turn up Channel II only just enough to fill out the tone to suit your preference... otherwise, turn the mids up, the treble ALL THE WAY up, and the bass down... almost all the way. Turning the bass down seems counter intuitive, but it tightens it up and makes it less "flubby." Forget about gain, I'm not even talking about gain... just the base tone. I guess you can hot-rod it or use a pedal or gainier pre-amp tubes or whatever suits your fancy or floats your boat. You can get your gain however you like to get your gain, I'm just talking about getting that edgy, crispy rudimentary tone you need for kick-ass metal. You don't need a modern amp... unless you are just in love with transistor distortion or doubled up rectification. In fact, doing this will come pretty damn close to a JCM800 sound out the door. I know, my amp has KT66's, but I've played through enough Leads and Super Leads w/ EL34's to know that this works both ways... in fact, it will sound even MORE modern through those (my KT66's are like low-grit sandpaper... very rough. The EL34's are like the fine-grain stuff, very smooth. Each to his own.) Just passing along the EXP!!! ...oh yeah, and it won't really work unless you PLAY HARD. I mean, attack that MF.