Bite & Punch are included in a pre-shape filter, located between the input tube and the first overdrive tube. To explain the Punch first let's think about a regular Bass control. A Bass control is operating very broadband, so when you turn down the Bass trying to get a tighter sound, from a certain setting downwards you're not only loosing bass, but also low mids - you're loosing the frequency range, from where the 'Ooomph' is/was coming from and you'll end up with a thin sound.
Hence I've designed the Punch control in a way, that you may attenuate or even nearly cut off the lower bass amount, but by keeping the low mids, so that you can dial in an ultra tight Heavysound no matter at what Gain setting, but the Ooomph doesn't disappear.
Another benefit of this solution is, that you don't charge the overdrive stages with too much bass amount, which is 'power eating', makes the attack slower - and you anyway have to filter it out later with the tone stack's Bass control, to not end up with a boomy and flubby sound.
So with the Punch control 'correct' set, you never can get a flubby, sluggish Leadsound - and with the Bass & Reactance (about Depth) controls then you only adjust, how 'big' your sound will be.
About the same with the Bite control, just on the opposite side of the guitar's frequency range. You know, when you try to get rid of too much brightness in the sound and are setting the Treble control too low, you easily can end up with a dull sound!
Not so with the Bite control, what's way more narrowbanded operating as i.e. a Treble control and is more focussed into the high mids & lower highs, by keeping the upper highs nearly untouched (that's the job of the Treble & Presence control!). So you can set the Bite control even to zero, to enable a round and sweet singing lead tone w/ tons of feedback, but not dull in any way! Or you adjust the Bite control to about 6 to 8, to obtain an aggressive, biting 'into your face' Heavychord/Lead tone.
In fact the Bite & Punch controls give you more versatility to fine-tune 'your' sound, than the common Treble-Mid-Bass tone controls.
Larry
