Here is what I’m trying to do. Its a mute switch (4PDT) that mutes a microphone and a piezo pickup. When muted LED should light up with power from the phantom supply. Its important that the pedal only draw power in MUTE mode. The difficult part is how to take the phantom power for the LED?. And without poping noice and other problems. This is my first idea. Haven’t tried it yet. Am I on the right track?
An externally hosted image should be here but it was not working when we last tested it.
I number your gray bars left to right. Note your XLR pins are wired to bars 4 and 5. Each of those are in turn wired to bar 3. So the XLR 2 and 3 are wired together. That will mute the XLR permanently.
BArs 6 and 7, you have two 1000uf caps in parallel. WHy not just use one 2000uf cap? That switches in across XLR 2 and 3? What is that for? You can just short 2 to 3 to mute a mic.
Before you get too far, why not sit down with a phantom power mixer, and see if you can power an LED from it in the first place.
BArs 6 and 7, you have two 1000uf caps in parallel. WHy not just use one 2000uf cap? That switches in across XLR 2 and 3? What is that for? You can just short 2 to 3 to mute a mic.
Before you get too far, why not sit down with a phantom power mixer, and see if you can power an LED from it in the first place.
48V / 6k8 Ohm=7mA. It is possible to light a small led, and You don't need a limiting resistor. The problem is, perhaps Your phantom supply will sag and mute the other phantom channels too.
For popping noise prevention, I would use a slow ramp circuit.
For popping noise prevention, I would use a slow ramp circuit.
Thanks! So I added a pair of 100K resistors for tapping the DC power. Will this work? Or is the input still shorted all the time? The other pair 300R is being used only for the audio mic mute circuit. They are not connected in this drawing but you see in my first post how I'm using them. Found that schematic online but its similar to many other mute circuits when phantom power is present.
An externally hosted image should be here but it was not working when we last tested it.
R5 limits the LED current immediately after flipping the switch.
C1 and R5 ensure that the current drawn from the phantom supply increases gradually rather than abruptly after switch on, reducing the risk of audible pops.
R3 and R4 limit the LED current to less than 0.96 mA, so you need a sensitive low-current LED (shouldn't be a problem nowadays).
It would make sense to increase R5 to 10 kohm or so, to limit the current peak after flipping the switch a bit further and to further slow down the phantom current increase.
It is still not clear to me how you want to switch the signal, as the first schematic with its hard short between XLR pins 2 and 3 makes no sense. You could simply connect a switch with a large capacitor in series between pins 2 and 3 of the output.
C1 and R5 ensure that the current drawn from the phantom supply increases gradually rather than abruptly after switch on, reducing the risk of audible pops.
R3 and R4 limit the LED current to less than 0.96 mA, so you need a sensitive low-current LED (shouldn't be a problem nowadays).
It would make sense to increase R5 to 10 kohm or so, to limit the current peak after flipping the switch a bit further and to further slow down the phantom current increase.
It is still not clear to me how you want to switch the signal, as the first schematic with its hard short between XLR pins 2 and 3 makes no sense. You could simply connect a switch with a large capacitor in series between pins 2 and 3 of the output.
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Thanks!!! Very helpful.
The first schematic was wrong and the hard short between XLR pins 2 and 3 was a mistake that happened when I tapped the power for the LED . The real audio MUTE is done with with the 1000uF caps. Switched with one pole on the 4PDT switch. Then two poles for the piezo a/b thing. And then the last pole for the LED.
Why do you need two 1000 uF capacitors if they are non-polar? If they are polarized, you could use two in anti-series (and put the switch in between just to make it look more symmetrical). Or do you want 2000 uF, but can't get non-polarized capacitors above 1000 uF?
One thing I overlooked: you need a resistor in parallel with the switch to get the capacitors to bias properly when the switch is off. Its value is a compromise between signal attenuation and capacitor voltage settling time; 10 kohm could be a reasonable choice.
One thing I overlooked: you need a resistor in parallel with the switch to get the capacitors to bias properly when the switch is off. Its value is a compromise between signal attenuation and capacitor voltage settling time; 10 kohm could be a reasonable choice.
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The schematic with two non-polarized 1000uF caps comes from a mic mute pedal I have. It works great so I wanted to clone that in my own build. Also thought about use one non polarized 2000uF cap instead but couldn't find one.
Hello Tyla, unfortunately I can't open the photos you posted.
I need to build a similar unit, could you please post your circuit again?
Thank you so much
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