Also, if you don't want such a drastic change try adjusting the capacitor around the feedback loop and you might have a simple low pass filter installed after the first 7199 stage. Some folks prefer the low pass filters and think they are a good idea but they do roll the amp off just above 20khz but in a nice steady slope. Without the filters output is good to over 50khz. I have some resistors on order to make some fine adjustments to the 6H30 circuits and when I do that I can get you exact measurements but this amp can do full out put from 20hz to about 50khz with NO visual distortion and about 1.5% measured distortion at 1000hz. It's a great little chassis.