It's a reference to the movie Spinal Tap which is a mockumentary from the 80s. They follow are a fictitious band and one of the famous lines from the move is the character showing his amp and saying this one goes to 11. 

grayruby

Yes, it's surprising! Never seen more than 10. But these are just number and can be written like 100 for 10. But only by writing it doesn't change much. I hope this one has more than 10 for real!