Hello guys,
I'm facing a kind of dumb problem here. I'm tryng to build a passive stereo volume controller to use on stage, just so I can attenuate the volume when the band is playing too loud and vice-versa.
It should be basically the input -> pot -> output, right?
But the problem is that, at max vol in the pot it all works fine, but when I turn it down a little bit, the volume drops a lot. For a 2% turn down in the pot I have a 95% decrease of the volume.
I've tried both log and linear pots, 10K and 50K, getting the sound from my mixer and from my laptop, all gave me the same result. The ground from both sides of the pot are connected, input on the right side and output on the center.
Any ideas what would be happening?
I've attached some pictures of my prototype.
Thanks a lot.
I'm facing a kind of dumb problem here. I'm tryng to build a passive stereo volume controller to use on stage, just so I can attenuate the volume when the band is playing too loud and vice-versa.
It should be basically the input -> pot -> output, right?
But the problem is that, at max vol in the pot it all works fine, but when I turn it down a little bit, the volume drops a lot. For a 2% turn down in the pot I have a 95% decrease of the volume.
I've tried both log and linear pots, 10K and 50K, getting the sound from my mixer and from my laptop, all gave me the same result. The ground from both sides of the pot are connected, input on the right side and output on the center.
Any ideas what would be happening?
I've attached some pictures of my prototype.
Thanks a lot.
Attachments
Let's check the wiring for starters:
The wiring to the pot looks correct (see first attachment), but could be tidier as there is potential for shorting of bare wires.
The bottom jack socket looks correctly wired, but check the top one as I can't see it clearly (see second attachment).
The wiring to the pot looks correct (see first attachment), but could be tidier as there is potential for shorting of bare wires.
The bottom jack socket looks correctly wired, but check the top one as I can't see it clearly (see second attachment).
Attachments
^^^^^ THAT
What impedance are your phones?
8 to 32 ohm or something in that area?
Your pots are the wrong value, by far.
I would go even lower than Galu´s suggestion, think around 50 ohm, or even somewhat lower.
And rather than volume potentiometers, which in principle control signal voltage, you will need rheostats (wirewound potentiometers) designed to control power.
Even if earphones receive a few milliwatts, that is already Power, not plain "signal".
What impedance are your phones?
8 to 32 ohm or something in that area?
Your pots are the wrong value, by far.
I would go even lower than Galu´s suggestion, think around 50 ohm, or even somewhat lower.
And rather than volume potentiometers, which in principle control signal voltage, you will need rheostats (wirewound potentiometers) designed to control power.
Even if earphones receive a few milliwatts, that is already Power, not plain "signal".
In-line volume controls for headphones are readily available (and inexpensive). I have a damaged one that I may take apart to see what's inside.
Thank you guys for the repply!
I'm using the laptop output for now because my mixing console stays at church, but I had the same problem there.
The console I'm using it's a Zoom LiveTrak L20 that has dedicated earphones out. The specs in their website are:
"Maximum output level: 42 mW + 42 mW at 60 Ω |Output impedance: 100 Ω"
Even using it in my console I should go this lower in the pot's resistance? All the projects I've seen uses 10k, 50k or even 100k.
I'm attaching some closer photos so you all can see all the connections more clear, but I believe all the connections are ok, because it works fine at max vol.
About the phone's impedance, yeah, it's a CCA CRA+, 23.5 ohm according to the manufacturer.
I'm using the laptop output for now because my mixing console stays at church, but I had the same problem there.
The console I'm using it's a Zoom LiveTrak L20 that has dedicated earphones out. The specs in their website are:
"Maximum output level: 42 mW + 42 mW at 60 Ω |Output impedance: 100 Ω"
Even using it in my console I should go this lower in the pot's resistance? All the projects I've seen uses 10k, 50k or even 100k.
Attachments
An in-line headphone volume control uses a 1 k ohm thumbwheel control.
You definitely need a lower pot resistance than what you are using.
You definitely need a lower pot resistance than what you are using.
A 1 k ohm audio taper should be a good match for your console output.
And I read that a 1 k pot is usually a good choice for most headphones.
And I read that a 1 k pot is usually a good choice for most headphones.