I don't have the unit, so it is a bit of a gamble I am trying to weigh the worth of I suppose. Would Eventide sell me an analog I/O board? I have done more research and it looks like the boards between the 4000 and the 4000B are mighty close, if not the same. Owner says this unit will not pass any audio even after he hits the continue button. If Eventide would sell the I/O board, I would be tempted to give it a go, heck I got lucky with the 4000B in my rack.