[Spandy87]

As the title says, the amp gain switches on the bottom are stuck to 'on', no matter how much I try to switch them to the other side. It almost looks like the little white plastic stub has broken off, perhaps it was forced too much previously. I have 2 questions about this.
 
1. Is there any sound alteration if I use the extra gain setting with a low impedance headphone?
2. Is there any way I can manually change the gain setting by disassembling the amp?
 
thanks in advance.