Treble/Brightness Cut

[no one ever]

I searched and came up with active tonestacks and gain-killing passive tone controls...





My Neovibe is much too bright... How can I tone it down a bit? Tried a 150pf cap to ground on the output, no dice... I don't quite know what frequencies constitute the grating "brightness" of a guitar, so I can't plug in numbers into equations to find a correct value.

help?

[no one ever]

should/can i reduce input impedance?

[Dave Eason]

I don't believe that would affect the brightness of it;  some HF roll off somewhere would be good,  a simple RC filter like that after the gain stage of the tubescreamer.

The guitar itself  has a relatively small bandwith generally speaking; I don't think you get many harmonics over 5KHz.  I could be wrong of course

[no one ever]

thanks, dave! on to "the technology of the tubescreamer" then

[no one ever]

edit:  jumped the gun.

[Dave Eason]

http://www.generalguitargadgets.com/diagrams/ts-808_sc.gif

look there (at the good old tubescreamer), R8 and C5 make up a passive low pass filter, with a cut off of 723.43 Hz.. which is fairly low, all though we're not talking "brick wall filters" or anything.  This is the 3dB breakpoint frequency, worked out by 1/2*PI*R8*C5.  Frequencies above this will be attenuated by a certain number of "dB per octave" - the "amount" of attenuation (or slope of the filter response) comes from R*C which is called the time constant.  OK with that stuff?
I was just thinking maybe you could incorporate something similar into the Neovibe at a suitable place.  Looking at that schematic, R6 and C3 are providing some more filtering in the form of bass roll off this time, the opposite of R8 and C5.  Simple stuff, but can dramatically effect your tone.  In effect, theses two filters make the TS808 a bandpass filter; i.e. you could "tune" any pedal into the desired frequencies you want to make it more bassy/more bright/a little less bright and so on.

[no one ever]

http://www.generalguitargadgets.com/diagrams/ts-808_sc.gif

look there (at the good old tubescreamer), R8 and C5 make up a passive low pass filter, with a cut off of 723.43 Hz.. which is fairly low, all though we're not talking "brick wall filters" or anything.  This is the 3dB breakpoint frequency, worked out by 1/2*PI*R8*C5.  Frequencies above this will be attenuated by a certain number of "dB per octave" - the "amount" of attenuation (or slope of the filter response) comes from R*C which is called the time constant.  OK with that stuff?
I was just thinking maybe you could incorporate something similar into the Neovibe at a suitable place.  Looking at that schematic, R6 and C3 are providing some more filtering in the form of bass roll off this time, the opposite of R8 and C5.  Simple stuff, but can dramatically effect your tone.  In effect, theses two filters make the TS808 a bandpass filter; i.e. you could "tune" any pedal into the desired frequencies you want to make it more bassy/more bright/a little less bright and so on.

I get that... problem is, passive stuff like that would (did, I just tried it) eat up lots of volume, and I don't know if there's a spot in the Vibe's signal path with enough gain to compensate for the loss.

[Dave Eason]

Yeah, I mean it has a convenient place in the TS808 between the two op amp stages.  Is there space for an active filter?  Maybe make a small break out board - even surface mount so you can fit it in if you have the facilities or have access to doing it.