Question about nominal voltages

[PmCimini]

Okay, so I was thinking about how to set an analogue delay to its best voltage and some questions came to mind.
Most BOSS pedals, for example (I used the BD-2 spec sheet) say they have a nominal input and output levels of -20dBm.

-20dBm @ 600 ohms load is 0,07746 Vrms

0,07746 * sqrt(2) = 109mV amplitude.

Is this correct? Because I know that some pickups can get way over 500mV easily, and I've seen pedals with huge gains that get huge voltages, and it looks rather weird, compared to the BOSS' specs.

Anyhow, I need to have a set voltage input "threshold", so I use the MN3005 to its max without an added "input level" control and without clipping... It should be a good level for bare guitars and for pedals. Any help?

[alanlan]

Nominal level can mean all sorts of things but generally it's just a normal operating level and with it, you would usually expect a certain amount of headroom before input clipping occurs.   So, it doesn't usually mean maximum input level.

Sometimes (usually with larger multi-effects processors) you get an input trim to accomodate varying input requirements.