Volume control value

[asfastasdark]

Hi, I'm buying some of my last parts for my build (a heavily modded Rat) today or tomorrow and was wondering what the effect of a higher or lower value volume pot would be. And more importantly: What the effect would be of putting a higher or lower volume pot before the circuit, acting as an input level control.

[petemoore]

Hi, I'm buying some of my last parts for my build (a heavily modded Rat) today or tomorrow and was wondering what the effect of a higher or lower value volume pot would be.
  Until you get smaller where signal loading becomes apparent [like 50k or 10k], not much. 1meg might sound a touch louder and retain a teeny bit more high end.
   And more importantly: What the effect would be of putting a higher or lower volume pot before the circuit, acting as an input level control.
  Probably very close in configuration, and effect, to the guitar volume control, which is a great way to try out 'pre-gain' controlling.

[kurtlives]

Hi, I'm buying some of my last parts for my build (a heavily modded Rat) today or tomorrow and was wondering what the effect of a higher or lower value volume pot would be. And more importantly: What the effect would be of putting a higher or lower volume pot before the circuit, acting as an input level control.

You'll see lots of fuzz circuits add a control like this. They call is a smooth pot and that's exactly what it does. Really cleans up the sound and takes the edge off. I always play around with an input pot like such when I am breadboarding.

Try it, might work for you.

[asfastasdark]

I know what the first pot was used for, just was wondering about the value. Thanks! 

Sander

[earthtonesaudio]

It's a question of how much current you have available to drive the next stage.

If the output impedance is low enough (i.e. current drive is high enough), you can use a very small value pot for the output volume.  The advantage to this is that the sound will not change much regardless of what comes after the effect. 
If you use a high value pot, the sound will change more drastically. 
This is because the input impedance of whatever follows the Rat can have more influence on the output impedance of the Rat.  For example if the Rat's output impedance is 100k and you plug into a 1M amp, no big deal, a 10% change is barely noticeable.  But if you plug into a Fuzz Face or mic preamp, maybe the impedance is 10k, and therefore the effective output resistance of the Rat is 9k.  If the Rat can drive 9k without problems, you might not notice, but what if it can only drive 12k?  Then you'll get a big volume drop and a reduction in gain.

Basically if you want it to be consistent no matter what you plug into, use the lowest practical value for the output volume.
Conversely, a passive guitar has precious little current drive, and so you would normally use as high value as practical for the "pre gain" control, to minimize loading on the guitar.

Experiment on the breadboard with any sort of effect really.  Just swap in different value resistors with the output volume control and notice how the sound changes. 

As a side note, I've sometimes noticed that you can cut down on oscillations in high gain circuits, simply by using a lower value output resistor.