If you are using a preamp (fx send from an amp, rack preamp, pedal preamp), make sure that you use the 6L6 PP mode IN pentode with the presence up (presence in the two notes stuff is not typical power amp presence). Try 12 o clock or 3 o clock.
Adjust depth to taste (too much and it gets woofy)
Select cab of choice but try moving the mic away from the centre of the speaker (5 or 10%) and also try mics other than the SM57.
Once you have that sorted, cut 6kHz to taste (this will depend on the mic and cab) and cut 800Hz by about 3db
The eq is to polish at the end not do radical stuff... I suspect your fizz lays in the poweramp (the model in the CAB)