I found it sounded bad when I got it above that. I figured maybe it would sound better at higher volume but I have not had the opportunity to really crank one.
That amp especially sounded much better with the volume up to a healthy level on the rhythm channel for the lower gain stuff. To my ears the lead channel sounded too narrowly focused frequency wise, lacking grunt in the low end and like there was an overdrive pedal always on, which has been my same issue with the DSL50 also. But keep in mind I'm talking about a first gen 5150 combo.