Mute Switch

[angusm]

I accidentally posted this in the wrong place. Hopefully, I have the correct place now.

I like to would make a simple mute pedal with a foot-switch. I tried shunting to ground, I still had some signal bleeding through. Any idea why?

So, I tried wiring a true bypass on a 3PDT, where, when engaged, both input and output are shunted to ground (instead of a pedal circuit) and this muted fully.  Is this an okay way to do it?

[GibsonGM]

Yes, it's fine. 

Lots of amplifiers use switching jacks - when no plug is in the jack, the input is grounded for silence, same thing.

Welcome to the forum, Angus.   

Of course, you can also use a set of poles on the 3PDT for an LED to remind you you're in bypass. 

[Kevin Mitchell]

Why not just ground the output and leave the input floating or rather - connected to a "bypass" jack so you're not grounding the entire signal? That would make it a mute/splitter instead so you still have a viable signal to use with the bypass jack.

If you don't want a bypass jack, then just use the stomp switch to break the signal and just ground the output.
Also, you may want a buffer for a bypass jack. - sorry, after thought. Otherwise just leave the input floating - no need to ground it if it's disconnected from the output.

And welcome!!!!

[angusm]

I tried just sounding the output and I have bleed. It's weird! I wonder if the wire is just not conducting/grounding sufficiently.

[Kevin Mitchell]

I tried just sounding the output and I have bleed. It's weird! I wonder if the wire is just not conducting/grounding sufficiently.

Weak ground maybe?
What are you using for a power supply? If nothing and the mute pedal is passive (no battery), your ground conductor on your instrument cable may not be great - or the ground further down the chain is the problem.

As I said, try breaking the signal between input jack and output jack. That way you have absolutely no signal on the output in mute mode. Instead of grounding the signal use a 1M + ohm resistor as a pull-down to prevent buzzing and popping.

[angusm]

Very helpful! Yes, just grounding one side still had buzzing. And it was passive. I suspect it is a combo of poor ground and need for resistor. I will give the resistor a try. Not sure I want to introduce an active box into a very quiet iso power pedal board, but perhaps powering it on it's own iso will make it quieter than not.

[angusm]

Just to complicate things...To do this with mono L & R outputs I could use a 4PDT, but no way to have an LED, correct?

Perhaps, I should just build an 2x mute or 2x ABY. For the current purposes, I'd always want A or Y with the ability to mute B, but...

1. I'd gain some knowledge of building one.
2. It can be used for other purposes (when I change my board as we all do!).

[GibsonGM]

It's perfectly fine to have the input just go to...input....and ground only the output, like Kevin was suggesting.  So you could do this with a 3PDT.   
And still have the LED.   This is just a switch, all passive....so it's either 'pass thru', or grounded.   

Is this just to mute the guitar signal (why mono....?) or would you want it after a chorus or some stereo effect?   The specific use you have in mind might be important or not.   Generally, it's ok to ground the output; I've never heard of a case where it was not, at any rate.

[GibsonGM]

Is this what you're trying to do?   EDITED to swap 'grounded input' for a 'grounded output' scheme

[angusm]

The Beatbuddy Main output also controls the amount sent to headphone. So, regardless of headphone volume if the main is turned down HP also turns down. I'd like to hear the BB for cue/metronome sometimes without the audience hearing it (e.g., intros, dropouts, "Yesterday" before the strings start and not have sped up my playing).

At this point, I've been using the BB in mono, but the option to send in stereo would be better. Again, I think I'd need two switches. I can't seem to find a schematic for a stereo mute box anywhere. Plenty of XLR mic mute boxes, but not what I need. If two switches for L&R then I'd just put them close enough to each other to press both with one foot stomp.

[angusm]

@GibsonGM
Yes, I will try it later today. If there is bleed with clips, I'll just solder it up to see if conductance is the problem. Regardless, adding the LED should also provide a better earth ground and solve the bleed problem. 

This stuff is so fun. I should probably get to building all those DIY pedals I ordered in the (Covid) summer of '20!

I'll also add resisters on the outputs just to be safe from popping.

[GibsonGM]

Well...you should be able to connect signal to ground, and get NO output at all, whatsoever. If you do means either the circuit isn't understood, or there's something else at work here!  Bad conductor or something.

I don't see where adding an LED will do anything to the ground...just remember, it wants to have a direct connection to ground without going thru any other resistors than the current limiting R you will include so it doesn't burn out   

Yeah, it's a great hobby! Can be confusing at times, I know, but very rewarding when something you made works right! Don't be afraid to ask questions.  If this is confusing someone can get you a drawing of a real, functioning must incl. the 'anti pop' resistors.

[angusm]

I meant adding the LED means adding power. Doesn't that provide a better (plug earth) ground?

[GibsonGM]

No, if anything it COULD (theoretically) cause more noise on the signal ground!  But it is only 9V so that is not very likely.   The only reason there would be any power in the box at all is just to light the LED.   In this case, it's wired up to be "on" when the circuit is in "mute", and off when signal is passing.

The 3PDT switch connects the middle row of lugs to the 'upper' or 'lower' switch lugs every time it is thrown. So you can see, "in 1" goes right to "out 1" in one position, and is grounded in the other.   Etc.    LED is disconnected when the signal is passing thru.

[angusm]

LED is disconnected when the signal is passing thru.

Sorry, one more question. when the LED is disconnected would that remove the potential for "more noise on the signal ground?" in other words, there would only be increased noise when muted?

[GibsonGM]

I probably shouldn't have even mentioned it, because you won't notice any additional noise from it being there.  The answer is yes, tho, current is only flowing when muted, LED is on then....currents flowing on ground CAN generate noise -- But look, the amt. of current there is miniscule...this is really only any issue if you're talking about grounds in an amplifier, or a very high-gain circuit, something that is using POWER (this ain't).    ESP. if you are running the LED from a battery, which is clean DC, thus no changing levels causing noise. 
Don't worry about the LED      Seriously. 


The whole thing should be mounted in a metal enclosure with an input and output jack, and the jack will ground the enclosure as well.   The grounded enclosure gives extra assurance that things like nearby bar lights don't couple noise into the system (which can happen to your pickups and all other audio goodies).   A stereo input jack is typically used to switch the internal battery on/off for longevity - stop me if you've heard this before...

There's always just more to learn, and nothing to be 'afraid' of.

[angusm]

@GibsonGM
So, grounding the input signal results in silence, but buzz. If I change the 3PDT to middle pole out so that I'm grounding the output I get silence and no buzz.

It's odd because the output is still grounded, just tip not shunted to ground when the input is shunted to ground.

I'm testing this using a Ditto looper and there is no buzz feeding back when shunting the output to ground only...That is, I can silence the output, hit overdub then play, unmute and there is not buzz.

Does this make sense?

[GibsonGM]

Hey dude, yeah, I kind of didn't 'get' what you were doing with this. What I had set up leaves the rest of the circuit open, so your observation of a more quite output was 100% correct!    I revised the pic a few posts back to reflect this - LED still will light in 'mute' if you so choose to include it.     My original was like unplugging the guitar and dropping the patch cord on the floor and leaving it, ha ha...it grounded the wrong side.    Well done, you figured it out on your own!   

Hopefully this takes care of what you want to do.

[amptramp]

If you are going to run an LED, there is no reason to connect any part of the lighting and battery to ground.  The circuit is just battery, resistor, LED and switch.  Nothing has to go to ground and potentially introduce switching spikes.

I have a couple of old Zenith Transoceanic battery / tube portable radios that have a dial light connected to a pushbutton.  The circuit is lamp, momentary switch and 1.5 volt battery.  This ensures that if the lamp is used, it does not limit the life of the expensive radio battery and no part of this circuit is attached to the rest of the radio circuit.