I have a Mesa Single Rec Series One (no "raw" mode) and I love the amp, always wanted a Mesa, but it has this fizziness to it when I crank the Gain. I am trying to get a metalcore sound from the amp I cant get where the fuzziness is coming from.

So my questions are two fold...

1. Is, or can, the fizziness come from the tubes? it has the stock Mesa pre-amps and 6L6's. I was thinking of getting new tubes for it (Eurotubes has a high gain kit of KT88's and a pre-amp cocktail). Would different tubes yield a better tone as well as kill that "fuzziness"?

2. The FJA mods...Anyone have any experience? i saw some vids on good old youtube of a FJA modded single rec and it sounded sweet, none of that "fizziness" and just aggressive! I am thinking of his standard mesa mod as well as his gain mob...any info on this or his mods?

Thanks for any help anyone can give me!
More gear laying around then I know what to do with, and still buying crap.
Do you mean the mix of high gain and tight bass? Or like noise? Cuz i think you picked the wrong amp for metalcore tone. I would have gone with a 6505 or something.
im a noob Dio so to play it safe here i can say when I have it cranked on the settings I have now (treble, mid, and bass all at 12 o clock) and the gain pretty much maxed it just has a fizziness, i dont know how to really describe it as anything but a fizz that is emitting from the amp that overlies the notes and chords i am ringing...
More gear laying around then I know what to do with, and still buying crap.
Switch your rectifier off "raw". As you have it it is in Tube recto mode instead of Silicon recto mode. Silicon will make it tighter and add a bit of volume. That could help. My thinking is that the fizz you hear is from having the gain maxed.
Turn down the gain and get a OD in front of the amp as a boost .. pretty much every metalcore band runs OD's its hard to get that sound without one .. I would change the tubes out to play it safe and mod it later if your still not happy with it .. all i have.
Caparison Angelus HGS, EMG 85/85 18V | Krank Rev1, JJ's | Mesa Recto Cab | Maxon OD808