Hello,
It is pretty easy. Imagine a voltage divider with 2 resistors connected in series. Now you replace the bottom one with a pot. However, note that it has attenuation even at max volume so do not use if your setup is poor on voltage swing.
This gives you logarithmic attenuation if you graph it. (YOU MUST GRAPH!)
This curvature is determined by the value of resistors you use for the top resistor. This should be close to the value of the pot at max attenuation, according to my calculation. However, you must grraph yourself for confirmation.
I had 50kohm Nobels, so I used 50kohms. You can pick larger value of the top resistors, but note that frequency response suffers if too large. Keep it at reasonable value.
The quality of the sound is determined by the quality of the top resistors. This resistor can range from wirewound, metal film, metal oxide, tantalum, carbon, to plate resistors. This is because the parasitic characteristics aren't so critical here. You get to fiddle around for your favorites!! Yey! (I picked non-inductive wirewound. That's my fav.)
Note the coolest part of all these. You can tweek the volume control very easily while keeping the many of the good things of stepping attenuator. If you want to swap the resistor, it takes 5 mins. If you want to swap the pot it takes 5 mins. It is very very easy to tweek this volume control.
Imagine doing that with stepping attenuator. Who in the right mind would swap resistors after spending hours soldering 46 resistors? So I usually never end up upgrading my steppers once I build them.
Tomo (the Tainter of the Purist Ideals!!
)
P.S. Note Linear pots should be used for this.