Proper resistance for volume control potentiometers...

[earthman]

I don't know if this is the right forum for this, but here goes....
I am trying to build a control box that will let me regulate volume on more than one set of speakers with out having to mess with all the inputs in software. I tried a 100k stereo volume control I got at Radio Shack, but the slope is too gentle, it doesn't attenuate the volume all the way when its all the way back, though it does raise and lower it. The power input here is negligible, since its in front of the amp, only a small fraction of a watt, at 4-8 ohms. Anybody have any ideas?

 

[blahblah99]

First of all, are you sure you connected the pot correctly? there are 3 pins. the ones on the opposite ends give you the full resistance value while the one in the middle plus either end gives you the adjusted value. One of end pins goes to ground, the other end goes to your signal (from pre-amp to pot). The middle pin is your attenuated output which goes into your amp.

100k should give you full attenuating (ie, when you turn it fully one way, its gnd'd), but depending on the input impedance of the amp, 100k may be a little too high.

Try a 10k pot.

 

[earthman]

That starts to make sense. The schematic from Radio Shack said to bridge pins 2 and 3 for the output side, maybe thats the problem. I have some 10 k ones too, though.

 

[dkozloski]

Make sure you use a particular kind of potentiometer called strangely enough a "volume control". It has a logrithmic taper to match the ears logrithmic characteristics so that all the action is not compressed to one end of the rotation.

 

[earthman]

Got it. The 10 k worked great. Thanks for the advice.