Modulaire et mixage

"pro" and "prosumer" audio line level is +4dBu, which is 1.228 volts RMS. That is 3.473 volts peak-to-peak.
Modular audio levels typically are 10 volts p-p (3.536 volts RMS).
"consumer" line level audio signals are -10dBv, which is 0.316v RMS, which is 0.895v p-p. (note that it's measured in dBv not dBu)

If you feed line level into a modular and don't change the gain much, you can get line level back out again. But since the signal level is lower than expected, the noise added will be much higher proportionally. If oscillators are mixed in or filters resonate, then much higher signals could go out than went in. While modular audio is typically 10v p-p, it can go as high as about 20v p-p.

-10 dBv (consumer line level) = 0.895v p-p
+4 dBu (pro line level) = 3.473v p-p
normal modular audio level = 10v p-p
peak modular audio level = 20v p-p

-10 dBv = -7.78 dBu
10v p-p = +13.2 dBu
20v p-p = +19.2 dBu

Most pro/prosumer mixers can handle at least +18 dBu on their inputs before they clip (more often +20 or +22). So can most pro/prosumer computer audio interfaces. Consumer level ones will distort at more like +10 dBu.