FWIW, I had an early OTB, think it was a 2010. It died a few months back and the amazing Orange pretty much gave me a new amp, minus the main cover bit which had my name on....and it was even out of warrenty - brilliant service
Anyhow i rememer the earlier 2010 model breaking up a lot earlier than this more recent model, 11 - 12 o'clock. I do however prefer the newer amp persoanlly and it does also break up around 1 - 2 o'clock with my speakers.