Why does a bright cap even work ?

[Iplayloud]

This is a noob question but let's say a bright cap sitting on a volume pot (like the 47pf cap on a BF Deluxe Reverb) why does it let high frequecies pass direct? Being an inverted carbon copy of the signal, it really should cancel these frequencies when being reintroduced in the signal path?

[Helmholtz]

A cap has low impedance at HF. So it shunts the upper part of the vol pot and feeds HF directly to the wiper.

It would only attenuate if it was wired between signal and ground.

[Enzo]

Because its unemployment ran out...


Inverted? Nothing is inverted in a volume control, with or without a brightness cap. Caps don't invert signals.

The bright cap on a volume control does nothing when the control is all th way up. Think about it, when the control is at max, the wiper and end of the pot are touching, shorting across the cap. At lower settings, the cap has reactance. The higher the frequency the lower the reactance. SO the cap offers a lower impedance path for the highs than does the path through the pot itself. SO they take that route. SO we thus see more highs leaving the control than we would without the cap. That makes it sound brighter.

[Iplayloud]

Oh ok I had the wrong assumption that the signal sine wave inverted each time it went through a capacitor, that the cap created an inverted copy of the signal. I think it's the case each time it goes through a tube triode correct?

[Helmholtz]

Depends on the circuit.

Referring to grid input the plate output is inverted, cathode output is not.
So a "normal" gain stage inverts the signal, a cathode follower does not.

There are more circuits.