Ok, thanks. So why would something operating on 3V clip at 1.23Vrms or 1.736Vpp? I'd expect the ADC to be able to get quite a bit closer to the rails than that. I learned something. Thanks.
Sorry for being a stickler about units, but on its own +4dB just means "x1.6 louder". dBu or dBV have set reference levels, so then you've got a guideline.
I still don't like them much. Why refer to something relative to something else? Why not just call it what it is? If the FV-1 clips at 1.73Vpp, we can say that. For me, referring it back to an (now) arbitrary 0.7746Vrms level and then saying how much gain you have to apply to that to get clipping is just overcomplicated. Others may have different views, obviously, and that's fine. It's not a religion, and my god of volts peak-to-peak isn't going to call me to war with your tribe because your god is decibels or RMS or something....

and thunk fark for that!