Adding low pass filter to output of a Pignose amp for Banjo

[fishfude]

Hi Folks,

My mate wants me to add a passive low pass filter to the output of his pignose amp, specifically for use with banjo. He seeminly wants a fair bit of high end attenuation and im thinking of starting around 2.5k and go heavy from there. I'm aware of the Stupidly Wonderful Tone Control(s), but I was looking for some suggestions of other options.

Many thanks as always,


ff

[anotherjim]

Surely for a Banjo you need a No Pass filter? 

Seriously, if it's just the line out you want to low pass, a capacitor across the output jack will do it (and simply).

However, the schematic I've seen has a fixed 33k resistor feeding the signal to the out jack tip contact, so for common capacitor values you have limited choices. (the filter is formed of that 33k resistor together with the additional capacitor)
2.2nF cuts 2.2 Khz. 1nF is 4.8Khz.
1.5nF will give you about 3Khz if you can find that value cap, or use 2 caps- a 1nF with a 470pF wired together in parallel (equals 1.47nF).
The filter cut off curve is going to be gentle, so it shouldn't make the top end too dull.