Decent Volume Control
I just finished installing a volume control in my latest arcade cab project.
This volume control project has zero need for programming or configuring, and is:
- analogue
- modular, meaning easy to change/replace with equivalent devices (within reason)
- simple, easy to install
- cheap, effective
All that is needed is a simple linear potentiometer and some audio cables. The exact pot value doesn't matter too much, it could be anything from 10K to 100K, but I find that the B50K pots, middle-of-the-range, work well with PC audio. So I've used a B50K pot in this example. They must be dual-gang pots, 2x3=6 pins, for stereo (two channels). Pots should only cost a few dollars.
In terms of wiring a simple linear pot for volume control, this isn't hard at all. There are 3 pins for each channel (x2 for stereo). The ground goes to one outside pin, and the input to the other outside pin. The middle pin is called the "wiper", and that will be the output.
Typical pot wiring for volume controlDo this x 2, total six pins, for dual-gang pots. With dual-gang pots, make sure to connect the two ground pins with a little extra wire. Done.
In some cases there is an EASY WAY, with
no very little soldering.
For the easy way, buy a kit of plastic headers. I got this one some time ago, seemed like a good idea at the time, cost maybe $10 or less. It has a bunch of standard sizes and pins.
The pins are a perfect fit for standard 5-pin headerAs luck (and standarisation) would have it, and because the pot pins are spaced at 5.08mm (2/10 inch) and the header pins are spaced at 2.54mm (1/10 inch), the 3 pot pins fit into the 5-pin header SNUGLY and PERFECTLY.
If you don't already have a decent crimping tool, spend another few dollars (probably a little more than $10) on one. Then you can just make the female pins, insert into the headers, and away you go. Plug n play.
So, no soldering required EXCEPT you
must connect the two ground pins. Easier to solder them at the pot rather than at the cables. There are convenient little holes at the base of the pot pins, you can just run an old resistor leg between them.
I used some blue and green heatshrink to remind myself which cables are input (green, from PC) and output (blue, to amp).
In testing, this gave me full range of volume, from really loud to super quiet. It is pretty good (though not perfect), would satisfy most people's needs. However, I note that most of the volume change seems to occur in the top half or third of the pot's range. More on that soon.
Complete, except: ground pins (blue) not yet connected on left; ground pins are connected on right Installed, front and centre. Can't see it? Good, it is meant to be subtle, though not hidden.
Still there? Well strap in, it is about to get exciting.
This pot will give your reasonably good outcomes, but. I know what you're thinking. "
This is a linear pot. All fine and good, but you need a log pot to properly reflect the range of human hearing in a smooth way across the range of the potentiometer"
Well, the theory says you are absolutely right. So let's dive into that with the next installment, which will be on turning this into a log (or anti-log) potentiometer.
Want to see more on this project?
Check out my Aussie lowboy build thread.