Hello,
I’m trying to build a simple mixer and i need to add one switch per channel to MUTE/UNMUTE the signal with a lightning Led when muted.
I tried different methods but i’m not happy with it or it didnt work as expected (clicks, pops and even a delayed mute…).
I did electronics at school but it was ages ago so i’m a little bit rusty with diagrams or schematics.
I’m building on stripboard so every stripboard image is welcome.
I’ ve tried with single latch relay, CD4053 and i have tons of other IC in stock.
Photo of my custom 3D printed rack with DIY 1U and 3U modules.
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Have you tried one analog switch (a cd4051 has 8) per channel (I’m not sure how a 4053 which is a multiplexer comes into this)? I’m thinking of muting the input signal by shorting it to ground (so there will not be an output signal) or alternatively similarly muting the output.
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hey mechamilk from my understanding what your saying, maybe im misinterpreting what your saying, but if you dont need CV input. have you thought of a 2 pole switch? use one side to switch the signal on and off, and the other side to switch the signal from +12v via a 2k resistor to the LED? maybe its more of a complicated ask but that what I would do 
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From the Facebook discussion on Eurorack DIY:
“You should use CMOS switches, a CD4053 could do the trick.
You can power them with +/-5v and you could even have the switch being controlled with voltage.
Anyway, no matter what way you choose to do the switching, to avoid clicks you need to have both sides of the signal AC coupled and have a resistor to the ground as reference. Usually, 100n and 100k will work and allow a 15hz roll off point”
Sounds like Klingon language to me…
I have no clicks or pops when muting, but when you un-mute there is a big pop due to my circuit (shorting the signal to ground).
A good read about muting audio:
https://sound-au.com/articles/muting.html?fbclid=IwAR3TzQ9LBWoFwyuzQxr4tGFbOV9HG9pWFfUa_oepfFjAN5gWS_4MyME6Zxk
I’ m trying this right now:
Any other hint or idea is welcome.
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I see so you want CV too. well funnily enough the way I do that in my modular, I have a module thats just a bunch of car indicator relays. it doesn’t pop at all. if you want I can draw out a schematic
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its much simpler instead of rescaling the signal
It would be great thank you!!!
Literally every time you say that, the answer is “Yes, please and thank you!”
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@lookmumnocomputer, was it the MEGA DUCK?
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Ah, its a patreon only link…
@Mechamilk It is, but I am just respecting the content. Please understand I only did that because I feel I would be breaking trust by providing the link to content directly.
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yes it was the mega duck! ive just left the studio now aaah and forgot exactly how I wired it up. its super simple a transistor and a relay. ill need to try and remember tomorrow. written it on my list of notes!
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Cool thank you! I hope it will work with single latch relays. I have only this type in stock.
Just watched the mega duck video.
Unless the relay you use has a built-in suppression/protection diode, you should add one to the circuit, like shown in the picture below. Otherwise the transistor will burn out pretty soon.
A 1N4001 or similar diode would work fine. You can safely add the diode even if the relay has one built-in.
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I think I have put in some diodes, I can’t remember ill take a look. however its been running rather freqyenclt for a nice long while but I think I did put diodes in. 1n4004 cus I have a load sitting around
but that circuit is basically what the mega duck is for anyone wondering!±
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Thank you all!
I have some questions:
1- Can you explain the use of the transistor in this schematics?
2- Can you confirm that is safe to use this to invert the flow of the current trough the coil of the relay to switch the relay contacts?
Thank you in advance.
I’m a New patreon today!!!
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I tried to make a soft mute switch both with JFETs and Vactrols but they either distorted or didn’t close completely. Settled to use SSI2164 with a resistor and capacitor on the control voltage. Works even at low sines.
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