Passive volume control?

[Phil Harborne]

Hi All,

I was looking at purchasing a logitech z623 system for my desk set up.

I currently have 3 inputs, tv, pc, xbox, so i have pc and xbox into tv, then an audio 3.5m out, and then just a straight 3.5m out from pc to speakers.

What i really want is a little external volume knob i can use for these speakers (i dont mind if it just does 1 of the above inputs)
I used to have bose companion 3 and the volume knob on that was perfect!

Is there anything around the uk you can buy that will do a very similar job ?

 

[nukemaster]

If you are a DIY type, you can just use a passive audio dual potentiometer(this is 2 variable resistors with an audio taper since audio would change at a very different rate with a linear version of this device.) as an attenuator.

You would bring the 3.5mm left and right into the 2 inputs of the variable resistor(potentiometer) ground the other end and take audio from the 2 wipers.

I am not sure how much "loading" this places on the device(many DIY headphone amps do exactly this for volume control so I do not think it would be an issue with most sources), but I have never had issues with it. If you had worries about loading you would have to buffer it with an opamp, but this requires power and cost.

If you have multiple sets of dual variable resistors you can control each input, but this starts to get messy and maybe an active mixer would be better(easy enough DIY with just a dual channel opamp. More opamps would be needed if you wanted to buffer each input.).

Check this out for more information
http/www.electronics-tutorials.ws/attenuators/attenuator.html

You may be able to get a passive device prebuilt as well.

 

[americanaudiophile]

http/www.ebay.co.uk/itm/IMG-Stage-Line-ILA100-RCA-Passive-Stereo-Volume-Controller-RCA-version-/111574670579?pt=UK_MusicalInstruments_Parts_Accesories&hash=item19fa5e5cf3
You could also pick up a used audio preamp that would give you input selection too.

 

[Motopsychojdn]

I'd just mod a rotary potentiometer just before the speakers themselves and mount it somewhere to suit
Moto