Sag is when the power supply of the amp can no longer meet the current requirements of the input in a linear fashion. When an amp is cranked wide open, hit a big chord and it compresses the first fraction of a second and then begins to 'swirl' in the harmonics and dynamics. In an amp with a hefty power supply, a hard pick attack will yield a crisp note and higher volume. The opposite of "tight".
The Fender Mustang Amps, Fender Fuse Software, and Remuda App, emulate this effect with the Sag feature.
- LESS cuts down the tube compression; Results in: more spongy feel, higher volume, more responsive attack, less negative feedback, more intense.
- MATCH emulates the particular model's tube compression.
- MORE increases the tube compression; Results in: less spongy feel, a little less volume, loss of initial attack, less intense. If you feel like using a compressor but you find it distorts your signal too much, try putting the SAG control to max, it acts as a gentle compressor effect, and at the same time it does not consume the STOMP place in your chain, so you are free to add any other stomp and still have some compression effect.