Some of the amp chains have a "fizz"

[cyrusadkisson]

Currently using dual rectifier and it sounds great except for this fizz you get when you strum or pluck a note. Can you hear it? Do you think it's fixable?

[gitterdude]

Many modelling amps, including the Boss GT and Line6 pedal boards, have a pronounced fizz.
One guy even built a "secret" and expensive box, the Radtone Harmonic Converger, to fix it.

I use the LSP Parametric_Equalizer_x16 to remove fizz from programs like Tamgamp and Guitarix.
A -36 dB notch at 5558 Hz with a 8.5 Q works great.