I've got a clock in my XA777ES. With the Audiomod, you don't have to have the power supply. Mine was installed by Modwright. There's definitely enough room. The frequency is around 11mhz. I decided to not get the power supply based on reviews at Positive Feedback that rated the significance of the mods. If you're going to do any mods at all, the clock is the first one priority wise.
I sent you an email. I upgraded to the SuperClock 4 and have a SC 2 available for the XA777ES
I sent you an email. I upgraded to the SuperClock 4 and have a SC 2 available for the XA777ES