Presence controls

Have to admit I never knew what they actually do but here's a good, clear explanation.

When playing an amp cleanly, increasing the presence control simply results in more upper midrange and treble.
When pushing an amp into distortion, though, the presence control behaves differently. It changes the “texture” of the distortion and adds complexity to the sound, making the amp feel a little “less predictable” for higher notes.

Spring reverb

Love the sound of the Catalinbread Topanga but as I record mostly and seldom play live, buying one would make little sense.

Instead, it struck me as more sensible to try to get the same sort of sound in Logic Pro, though the spring reverb sounds in Space Designer lacked the liveliness of the Topanga, particularly in the area of 'splash'. Eventually settled on a 3rd party plug-in, Aegean's Spirit Reverb

Generally, pretty happy with it though as it's new I must admit I'm saturating the guitar tracks a bit, and still only using the Vintage Spring settings.

More examples of what it can do here