Also good to call out the better digital reverb units do this:
1) Split analog signal
2) Pass through one side to output (probably with a signal boost)
3) Take the other side & digitize
4) Apply effect to digital signal
5) Convert output digital signal to analgo
6) Mix into the output of step 2
I find this to be a very audible difference.
But what changes in a digital spring reverb is not that you switch some analog circuitry for digital. Either you simply attach a DAC to the input and an ADC to the output, but that doesn’t really mean that you get rid of analog circuitry. Or more likely, you’re replacing mechanical parts for a software model that achieves a similar sound. What’s interesting in that is not that you go from analog to digital, but from real mechanical equipment to a software simulation.
There are a lot of digital effects out there. They digitize the input signal, do some calculations and again convert to analog for the output. A lot of reverb units are like that. Some amplifiers have digital reverb builtin.