Presence Knob

[AZanshin]

I have tried this fully open and off on my amp and am not quite sure
what this knob achieves towards the sound produced from the guitar.

Could anyone shed some light on this

[billkath]

It achieves presence. In other words-it boosts the hi-mid range of frequencies. My advice is to leave it alone for jazz-off position.

[AZanshin]

Thanks Billkath for clearing that up

[kenbennett]

Technically, it's a circuit that feeds part of the signal from the output stage back into an earlier stage of the amplifier.

The term 'presence' was a buzzword in the early days of recording that meant 'as if you were there in person', like present at a live performance rather than listening to a recording. I think that's why they called it 'presence', just because it was a popular term for an experience sought after by audiophiles.

It does give the amp a little more ability to 'cut through the mix', to use another shadowy cliche, without much increase in the volume.

[kamlapati]

On my old Fender tweed amps, the presence knob not only effects the highs, but it also changes the amount of "grit" or distortion on the highs. Once you hear it, it's unmistakable.

It makes sense. If you change the gain of a frequency band in an amp that is running near distortion, it's gonna add some distortion in that frequency band.