Great tone doesn’t come from EQ.
Treble controls make treble notes louder (or quieter). Bass controls make bass notes louder (or quieter). What they don’t do is make your treble rich or sweet, or your bass full, warm or gnarly. They don’t really change the harmonic balance of your sound. They can’t make weak sounds come alive and, equally, they wont make a good sound into a weak one.
Great tone exists -inside- the circuit.
If you boost the high frequencies, in the circuit, just before each distortion stage, by just the right amount (and then correct that boost after to make your sound balanced) then a smart electronic engineer can design a dirty, harmonic-rich high end and a smooth, full low-end, perfect for rock, for example. Or you could boost the upper mids and cut the highs, then restore the bass after the distortion stage, which would cause a liquid lead with clipped mid-frequency notes that generate lots of harmonic content at the same time as having sweet, clean top and bottom ends.
This complexity is something ‘tone controls’ just can’t achieve.
What are tone controls good for then? Tone controls are for volume. If your high notes are too quiet, then turn up your treble. If your bass notes are too loud, turn down your bass. They’re great for balancing your sound out. For equalizing the volume balance.
Wait…Yes! That is why it’s called EQ!
So now you know: Don’t expect tone controls to open up new sonic territory, or give a lifeless distortion new character. They’re really useful tools, but they just don’t do that.
Great tone comes from the heart; the heart of the circuit, and the heart of musician.