Thread: hardware volume control

wire it like this

(o) front view (cool ascii view hey)
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pin 1 is ground
pin 2 is output
pin 3 is input

so for the left channel......

the active wire from the sound card, goes onto the 3rd pin, your amplifer input hooks up to pin 2. The shield from both amp and sound card, go to the ground pin, but unless you've done this before, it may be a tad hard to understand.

why? because 10k impedance had to match your soundcard output and your amplifier input.

If you have them unbalanced, you may experience noise from the amp when you have the pot in the halfway position.......then you will have to build a matching resistor network.......

But in most cases just wire it up and it should work

Enjoy

[This message has been edited by Bj (edited 03-20-2001).]

BJ explained it perfectly, but there is one thing to add:

Be sure to get a high quality sealed pot. Normal pots are very cheap and wear out quickly with any sort of use. Also, sealed designes keep the horrible dust found in cars out. When I clean out my player, the rag comes out pitch black from all the greasy dust that is formed. Terrible stuff. Normal pots will last a few months then become crackly.

You will pay more for a sealed pot (probably close to $8 a piece) but it is worth it. Multiturn is not necessary.

A company called Xicor ( http://www.xicor.com ) makes some really neat little digital pots. They are basically a small DIP package with no external components needed.

You hook 3 pins up just like a normal pot, and then connect 2 momentary switches (or a rotary pulse switch if you want an "analog" feel to it) to the digital Up/Down inputs. It works exactly like a digital car stereo with up and down volume buttons. If you hold down a button it will accelerate to zero or full volume.

They have several models with different resistance values and the IC's even have onboard nonvolatile flash memory to store the volume level even when power is removed! They offer linear and logarithmic versions (for audio).

For a stereo signal you could gang two together so they step in unison. There's even a mute input you could connect to a small switch.

I have a couple of these I was going to mess with but never got around to it. I'll be sure to post some info if I ever use them.

I've completed the mod sugguested by Arby and it works quite well I have a pic of how to wire it up that should answer any questions. If it doesn't answer all the questions let me know.

Here's the pic sblive.ufdah.com

Thanks Arby, I almost went through the work of using two pots for the front and rear channels but this was much easier plus there is no loss in sound quality.

That's cool. I didn't know about it muting as well.

I made a software volume control using a rotary encoder (i.e. jog-dial). So I've got a knob up front that I rotate for volume, and push to select volume - bass - mid - treble - balance - fader. If you're interested, here's a description:
http://www.nfra.nl/~smirnov/jogdial.html