Well, I finally tried to use it last night since I had no access to the pressbox prior to last nights game. Unfortunately it didn't work at all. Now granted, I didn't do the soldering myself and I'll have to test the circuits. Near as I can figure with my mechanic mind, the pins 2 and 3 on both sides of the switch should have continuity between them unless the switch is depressed. Then, with switch depressed I should only have continuity pin 2 to 2 (male and female) and 3 to 3....As far as your suggestion on VOX, I'm looking for the exact opposite...I don't want it to work unless I'm making an announcement or calling a play. The last thing I want to do is comment to someone else in the booth that the "Ref is full of Bleep and have it come over the PA. Oh, and Roger beeps drive me nuts...NASA withstanding....

Your switch may not have worked because it was normally closed? Instead of normally open, or vice versa?

DPDT switches are on in both directions. So I don't think it's really a matter of turning the microphone on and off, but actually just having the microphone always muted, with a momentary interrupt to on. So, just flip your connections on the switch. You want push to talk not push to mute. And that's those other two connections on the DPDT switch. You know, this is not rocket science. The microphone should always be on and muted. Only interrupting the mute to speak. And not the other way around.

In a similar scenario, back in the day, in radio, each microphone in the studio had a cough switch. And this was reverse logic to what you want to do. Same switch. Wired differently. Simply wired in reverse. So instead of a cough switch you want a talk switch. This is something that has been done since the 1950s, and maybe even the 1940s? But I remember this from my earliest days in radio stations in the early 1960s that were still utilizing 1950s equipment. And it's something you don't really see much anymore since most radio stations now have the announcer (DJ) running their own equipment, where it is just as easy to turn off their microphones, when they need to cough.

Bottom line, this should be as simple as building a crystal radio. And those were completely passive radios with no active circuitry. Required no power. Delivered low fidelity, amplitude modulation radio. And the greenest receiver on the planet.

You know that when the next electrical holocaust occurs, FM and digital radio will cease, and we will go back to low fidelity amplitude modulation, if there is any electricity left at all to transmit with. This scenario could happen Morse or less, when the magnetic poles reverse?

Don't throw out your spark gap, continuous wave transmitter.
Mx. Remy Ann David

girtski, post: 393692 wrote: Well, I finally tried to use it last night since I had no access to the pressbox prior to last nights game. Unfortunately it didn't work at all. Now granted, I didn't do the soldering myself and I'll have to test the circuits. Near as I can figure with my mechanic mind, the pins 2 and 3 on both sides of the switch should have continuity between them unless the switch is depressed. Then, with switch depressed I should only have continuity pin 2 to 2 (male and female) and 3 to 3....

Correct. Check it out using a multimeter on continuity or low Ohms range with the box disconnected from both the mic and the mixer. Also check that XLR pin 1s are interconnected and that there is no connection between the switch circuitry and the pin 1s.

I have a Normally closed switch with only 2 terminals. I checked continuity from pin 2 to 2 and 3 to 3 with the switch activated and inactivated. It worked as expected. (continuity across 2/3 with switch inactive, no continuity with switch active). I checked 1 to 1 and have continuity regardless of switch position.

However I still don't have functional use of the setup. I also checked to see if there was continuity in either switch state while checkin pins 2 to 1, 3 to 1. I have no continuity there.

It has me baffled. When I activate the switch, I get a blink on the LED's of the mixer, but no audible sound (other than a pop) when speaking into the mic even at max volume. I'm about ready to just buy the "Whirlwind" PTT switch...I thought this was a simple little project. That always happens though. The simple stuff isn't and the things I put off forever take me 20 minutes to complete. There are 4 contacts on the back of the XLRS...What is the 4th for? Both XLR connectors are mounted in an alumnium project box. I've tried this withoud mounting the XLRS and it didn't work there either>>>>

Well, there must be something wrong somewhere, assuming the PG48 works correctly when plugged directly into the PA mixer.

The last thing to try is a continuity test of the switch box plus the cables. Unplug the XLR cables from the end of the microphone and from the input to the mixer, but leave the other ends connected to your switch box. Now use the continuity tester between the free ends of the XLR cables checking between ends pin-to-pin with the switch pushed and not pushed. This needs three hands (or two and a big toe).

The fourth contact on the XLR sockets is likely to be the connector shell and can be left unconnected. Mind you, the other three have to be the correct three...

PG48 works well without the box and with both cables I used to connect the box. I also tried my Beyerdynamic M68 mic and cables to no avail. This seems like a simple task...I would have to take the suggestions forward for killing the pop if I could get it to work like this. I'm lost...Will poke around again later.

The logic to your wiring is 100% wrong. When you say, you see continuity on your DMM, that means, it is shorting the microphone off. When the switch is depressed, you should see no continuity. So again I must ask you, how many contacts are on your switch??? This is the world's simplest project. So listen to me carefully. Pin one is ground. And if your switch has only 2 contacts on it, it's not a DP DT switch, which has, 4 contacts. If it doesn't have four contacts? Then it's not a DP DT switch! It is an SPST switch with only two contacts. With a switch like that, in that scenario, you would simply use this switch on pin 2. Meaning than that, XLR, out of the microphone, the switch would be connected to only and only pin 2, microphone output, to pin 2 XLR microphone input to the PA on pin 2. This means that pin one passes through microphone XLR to PA XLR input. Pin 3 from the microphone XLR output to PA in XLR pin three should also always be connected through. Then the switch is only there to connect pin 2 from the output of the microphone to pin 2 XLR input into the PA. So you press the button, it completes the continuity from pin 2 XLR from the microphone to pin 2 XLR inputs of the PA with a switch that only has 2 contacts. This makes it a simple series in-line function only affecting the connection of pin 2. There should be no other connections. The switch simply creates the continuity from pin 2 microphone output to pin 2 microphone input on the PA.

This method of switching may still cause a pop? Because it's basically connecting and disconnecting the microphone from the PA. This switch can have no other connections to pin 1 or 3 if it only has two connections on the switch. Because of this switch is connecting pin 2 to pin 3 it's simply just shorting out the connections and not connecting the microphone to the PA. So this which is either on when depressed or off when not. In a switch that has 6 connections, it would be a DP DT switch and the wiring for that, for this application, would be completely different. So without the correct switch, the wiring scheme has to be completely different. You have a simple in-line switch that only allows continuity, when the switch is depressed. So it cannot be shorting anything out, but must be utilized to actually create the continuity pass through with pins 2 XLR out to XLR in when they switch only has two connections. This is not rocket science. Two connections on a switch is a simple on-off switch, only allowing continuity to pass through, when the switch is depressed. So pins, 1 & 3 from the microphone output to the PA input are always connected. Pin 2 output from the microphone is then interrupted from pin 2 XLR input on the PA. Depressing the switch simply connects pin 2 output from the microphone to pin 2 input on the XLR to the PA. It's a light switch!

With your other wiring scenario, you are simply shorting the microphone out every time you press the button. So you get nothing, that way. The continuity you are lacking is simply in your thought process and not the switch wiring. Only when the wiring is correct in your head, will the switch work. So with only two connections, the switch only shows continuity on its contacts when you press the button. So this which can either be used to complete a circuit or not to complete a circuit. The switch cannot be used any other way with only two connections on the switch. It is not a double pole, double throw. It's a single pole single throw, with only two connections. So it can only pass. When pressed and not pass. When not pressed. It cannot be used to short the microphone and short the input to the XLR. It's not the right kind of switch to do that. You should have learned this in the sixth grade, yourself. And this could still cause a pop to be heard through the PA, because it would be connecting and disconnecting the microphone on pin 2. The PA may have 48 V of phantom power on it, which should be turned off on the mixer if possible, and that's usually possible. Because if the phantom power remains on, you will always get one hell of a pop! And you don't want that. Obviously you are not the electronics instructor at the school. This is child's play. This cannot be any simpler. Two contacts = only pass through or not pass through and not intended for shorting purposes. In this scenario.

You can think of this switch in terms of an auto assembly plant. When the switch is pressed, the cars are moving down the assembly line. When the switch is not pressed, the assembly line stops moving. It's an on off switch and can be used no other way. So, the switch only allows for continuity on or no continuity. Which means it would only be utilized on pins 2 on the XLR cable. So either pin 2 on or to turn pin 2 off. It would be only used to connect pin 2 to pin 2 from XLR microphone output to PA XLR input. If you cannot turn off the phantom power of 48 V on the mixer, you will not be able to live with loud popping sounds every time you press the button to turn the microphone on. And you can't have that happening. Almost every PA mixer that offers phantom power also has a switch to turn the phantom power off, and it should be off with the microphone that you are using. And you do not want to use a condenser microphone, which the PG 48, thankfully is not and it does not want to see that 48 V switch on, on the PA mixer. Even with that switch off as it should be on the PA mixer of the 48 V, it still may cause inordinately loud pops every time you press the button. Not everything can work as you want it to when you do not understand how to purchase or wire the correct switch. Radio Shaft actually has both types of switches available, and this really ain't the right switch. And you have it wired the wrong way because of that. You must be able to understand simple DC theory and you don't. Your problem is like putting 2 batteries into a flashlight the wrong way. If plus is not followed by minus, the flashlight will not work. You can't have plus, to plus and minus to minus. Otherwise, the flashlight will not work. The same can be said for this, SPST switch. It's either passing continuity or not passing continuity and would have to be used in-line. Only on pin 2, not connected to any other pins. It is simply there to connect pin 2, to pin 2, and nothing else. If you don't get this right? You're going to have to go back and repeat the sixth grade. Otherwise you will fail.

Think of the switch this way. If you disconnect the plus cable from your battery to the plus cable to your car engine, your switch would go in between those two contacts in your car would only start when the switch button would be depressed, because that would be the only way, the batteries plus connection to the car engine plus connection cable to the engine. Without pressing the pushbutton, your car would not start because there would be no connection from the plus side of the battery to the plus side of the battery cable to the engine starter. If you were to install this switch in your dining room, your dining room light would only come on, when you hold the switch button down, because it is a momentary switch, that is spring-loaded. So they don't make good dining room light switches. They don't make good switches to connect your battery from your car to your engine. It simply there to create the continuity from a battery to a light bulb so to speak. You wouldn't want to be shorting out your battery and shorting out your light bulb would do nothing. So you must use it in line, in series to create or defeat continuity in the connection.

Please do not go to work for NASA.
Mx. Remy Ann David

Wow! This is the longest directions I have ever written to turn on or off a lightbulb. Think of pin 2 as a switch to turn on and off a lightbulb. It is only going to connect pin 2, to pin 2. When the button is not pressed, pin two will not be connected and the microphone should make no sound. This is not the ideal way to do this with microphones. You could just get a simple desktop push to talk CB/2 way radio microphone, which already has the proper internal wiring with the proper type of switch.

Wax on... wax off.
Mx. Remy Ann David

Remy, my reading of it was that he had a push-to-break switch. I advised him to wire all three pins on the male XLR to the corresponding pins on the female XLR, and then connect the switch across pins 2 and 3. This should work as a push-to-talk with or without phantom power present and furthermore will not cause an open-circuit input condition when in the switch is in the mute position.

The only muddying factor is that his XLRs have a fourth solder tag, which is probably the shell.

Thank you Boswell. You nailed it. I never claimed to be an electronics genius, but Remy makes me and others here out to be a moron. Remy, Do you own the site? Otherwise you should be banned due to poor decorum. I can't imagine how you obtained Moderator status.

I never mentioned DPDT in any of my previous inquiries. I have a NC spring loaded 2 pole switch which, in my scenario, shorts pins 2 and 3 together unless I want to talk. That was and is the direction provided here. I simply spliced into the wiring going from 2 to 2 and 3 to 3 and ran tags or legs up to each pole on the switch. I still don't understand why it doesn't work since in effect there is no interruption in either circuit when the switch is depressed. The ramblings above further enforce my desire to simply buy a switch from Whirlwind who makes one with all the anti-pop do-dads included. I just thought I'd give it a shot since I have some talent and understanding of general electric circuits. I did not understand the shorting of 2 and 3 together to effectively mute the signal. It would have made more "sense" to me to interrupt pin 2, 3 or both with a DPST switch. But it was my understanding based on input here that doing so would cause unwanted noise. I'm not done yet...I just got out of my kindergarten class.

I'm sorry ya found me offensive. I've been going through some bad times, and I guess it was reflected in my response? My bad.

Boswell advised you quite correctly. After reading numerous posts here on this, it seems we all had the switch nomenclature quite screwed up. I made a mistake. When I said it had four connections, it's six, for a DPDT switch, of which, some are just on or off. Some have a center off so that top or bottom can be on. Some have spring-loaded paddles in a single or both directions.

Not to be rude but if you had some understanding of basic electronics, you wouldn't even be asking this question. Because this is basic electronics, and you're not there yet. This isn't even basic electronics. It's before basic. Basic is simple DC theory, which is what we're talking about. You come to a professional audio site, asking how to boil water. And then telling us the water isn't boiling. May be having trouble making a fried egg with the egg rolling around in the fry pan? What's the matter with the egg or is it the fry pan?

And even up to now, you have to stoop to buying that gizmo from Whirlwind because you still can't wire a freaking switch. And so you have an understanding of basic electronics. So where is it?

What made me a moderator? Not sure? Maybe it's because I know something? Maybe it's because I saw pages of posts to try to explain how to connect less connections than pages posted? Maybe it's because I saw numerous suggestions given to you with no results? And back and forth and back and forth, and the guy still can't wire a stupid switch. Who helps you in the bathroom? You must have problems in their also? What are those funny cotton things on a stick with a string used for? Which direction do they go? What is the cardboard for? Am I supposed to take the cardboard off first? And how many pages need to follow to explain that? I mean do you even know how to get food out of the vending machine? You put the coins in the bottom, where that little door is but nothing comes out? And I can see the coins just sitting there. What's the matter with the coins? Yeah, sorry, I guess I am being a bit brutal? What? You never had a teacher yell at you? Folks never raise their voice to you? I mean, when you're stupid, and things are going on for four pages with people trying to help you and you still don't get it, you don't think you're going to take some flak? How do ya think you would do on a sports team? What will I do with the ball? Follow?

To be honest with you, there are more than a half a dozen different ways to get push to talk. There are good ways. There are not so good ways. There are bad ways. There are very noisy ways. There are complex ways. There are simple ways. See? Six different ways. I would go into more detail, but unfortunately, you wouldn't understand it. Whoops... (blush) I said there were six different ways. There's really seven. The seventh one is, you go to the store and just buy a gizmo. Which makes a lot of sense because obviously you didn't build the microphone. You didn't build the PA system. How could anybody expect you to screw in a lightbulb? I mean how many engineers does it take to explain how to wire a switch? Sorry half a dozen very competent teachers explaining it to you from electrons to light. And you still haven't figured out how to wire a switch. Sometimes I get a little upset, thinking maybe people are just trying to egg somebody on? And this guy is writing some kind of a personal dumb ass joke to see how many highly skilled and competent engineers will respond to how to wire a switch? When I keep telling them it doesn't work (hee hee)?

So I apologize because that above scenario has occurred here on numerous occasions. And you have an awful lot of very smart and talented people here. And everybody who has explained how to make this work hasn't worked for you yet. That would make you truly either a jokester? Lousy student? Completely inept? It's a switch. I mean, some of these questions and their following responses go from comical to wisecracking. Personally, I was really hoping to see a response to someone here such as " thanks it works great now!" And then I see he's still having trouble with the freaking switch. So I'm sorry. I mean, I know nothing about medicine, but if I had to remove somebody's appendix with a broken beer bottle, I could. You just do it. Maybe it's because I'm frustrated that I was never a drill sergeant?

I did try to join the Marines, Air Force, Navy, Army. I didn't bother with the National Guard or the Coast Guard. I was an accomplished student pilot at 13 who because of age, could not yet Solo. Even though I was ready to. FCC licensed and working broadcaster at 15. Recording engineer at the biggest studio south of New York City at 17. Working with licensed electricians and 18. None of them took me because I got busted for a single joint. When I was 18. So I had to go on from there, as the overnight diss jockey on the number one rock station in Baltimore at 19. Then engineering at the number one and oldest, most prestigious Baltimore AM station at 20. Designed Baltimore's second-largest recording studio where I custom built a 24 track recording console from scratch, also designing, installing, wiring the entire studio/control room at 21. Decided I should move up to a hit recording studio in NYC. Didn't like getting mugged so I resigned and went to work for a multimillion dollar advertising agency, producing thousands of commercials and fully orchestrated New York style jangles for a couple of years until I went to work for one of the most legendary tape recorder manufacturers in the world for about a year. Didn't much like working in a factory even though I was the Quality Control Manager, File Test Technician and a hopeful genius that would save the products existence. But that was a factory, so I went to work for NBC radio and TV, designing and building custom consoles for new control rooms, one other major audio engineers doing the most prestigious network news and political shows, game shows. For about 20 years. Finally saying screw that, I'm just going to go ahead and build one of the top remote recording trucks in the country for myself. When I was 37, 21 years ago, and I still run today. So I guess I really don't know much about a switch? I've only wired a few thousand of them. Maybe one day I'll remember how many contacts are on a DPDT switch? Because it certainly isn't 4.

I've been known to sometimes be inappropriate. Again, sorry.
Mx. Remy Ann David

Well, whatever your current circumstances, that was some sort of backhanded apology!

Can you explain to me why you repeated (two years on) your erroneous assertions that phantom power would be interrupted by a switch shorting pins 2 & 3? Strange that, considering all your self professed genius and experience and that you acknowledged on this thread that Boswell and I were "probably" right about phantom power not being interrupted. It seems to me that the independence of common mode and differential signals on a balanced line is pretty basic (otherwise why would a balanced line reject common mode hum???) but, for all your experience, seems to be something you do not yet fully grasp.

All your experience does not make you right nor will regaling us with your life history change that fact.

So, the resume not withstanding, should I be interrupting pins 2 and 3 with a switch or shorting them together to obtain mute status?

So, the resume not withstanding, should I be interrupting pins 2 and 3 with a switch or shorting them together to obtain mute status?

Yes, that's the correct function - a push-to-break switch across XLR pins 2 and 3.

I was puzzling over what could be wrong with the wiring, and thought of another check you could try, again using a continuity tester. This time, connect a single XLR cable from the switch box input round to its output. When you measure inside the box, there still should be no connection between pins 2 and 3 when the switch is depressed, and no connection at any time between pin 1 and either of pins 2 or 3.

I will try that bit of troubleshooting when I get home... There is probably something very simple going wrong here that I'm not finding. Thank you.

Well I actually do understand. It's you that's not understanding.

I'm also thinking that there is this possibility that this mixer that you are feeling may actually be an unbalanced input on an XLR? This has been done in quite a few school systems over the years with earlier systems. And then only two connections are utilized of the three pin XLR. These are high impedance unbalanced XLR inputs. Connections are generally ground on PIN 1, high on 3. This could also be a cause of your incongruent connection problems? But if phantom power is available on this mixer, at this XLR input, these are low impedance balanced XLR inputs.

Either way, if you can not disable phantom power, I can pretty much guarantee that every time you key your microphone, you will produce quite an astounding loud pop.

By the way I usually answer a lot of these, after a long day, late in the evening, early into the wee hours of the morning. So excuse me for occasionally making a dead on my feet, midnight error. Seems you've been making yours for days? So don't be giving me any crap, thank you. We are all here desperately trying to help you. You're welcome.

Really now...
Mx. Remy Ann David

Remy,

You seem to have this whole thread mixed up. I don't know who your last response was directed to but whatever your latest response does not make much sense. The ORIGINAL enquiry on this thread was regarding shorting pins 2 & 3 on a phantom powered mic. where you repeatedly asserted (incorrectly) that shorting these pins (the differential mode) would somehow short the phantom power (the common mode). Not so. Having almost accepted this in your post #23, two years later in posts #29 and #31 you managed to reiterate the error although it was irrelevant to the new enquiry in post #27.

We are now on the third query of this thread which again does not involve phantom power at all, as girstki stated in his original query on this thread, that he is using a Shure PG48. This is the guy we are currently trying to help. Maybe you should just familiarise yourself with the whole thread again.

In your normal sign off prose, you are beginning to pop me off. What's the point in telling people who have a problem what moron's they are (your words) and what a genius you are (again your words) when all we are trying to do is help! This may be a pro forum but treating visitors in this way is certainly not "pro".

Finally, I'm glad you understand and am sad that it is presumably I that does not. That's OK with me but only when you show you actually do understand by giving the right information. Balanced signals are after all, only useful because of the independance of the common mode and differential signals they encompass. That in a nutshell means you can do what you like with one WITHOUT affecting the other. Short pins 2 & 3 as much as you like in a true differential system, it will not affect phantom power.

Firstly, common mode rejection will do you no good when 48 V is being connected and disconnected on a live microphone channel. Whether it's through shorting the microphone or terminating the Phantom, reconnection will still cause a pop. It won't necessarily take out any other live phantom powered microphones on other channels. But that's not the point. That's why it would be good to turn off the Phantom on that PG 48 so as not to have it at all. There are better ways to do this but it is beyond the scope of the request.

Guess I shouldn't be answering these questions anymore at 4:30 AM in the morning?
Mx. Remy Ann David

Remy,

You are being remarkably consistent in missing the point! Whilst I quite agree that turning phantom power off and on to a condensor mic may well produce clicks and pops, shorting pins 2 & 3 will NOT affect the phantom power. Pins 2 & 3 are (or should be) at equal DC potential when phantom power is on. Hence shorting 2 & 3 causes no DC flow between the pins when shorted. Hence the phantom power (D.C.) will be unaffected and the mic will still be powered. Hence there should be no clicks and pops due to the power being turned on and off.

This is just the same the other way round. The differential signal still works whether phantom power is on or off. The whole issue I have had with you is your insistence that shorting pins 2 & 3 will turn off the phantom power and hence you will get clicks and pops. This is just not true as both Boswell and I have tried to explain. It seems like I am banging my head against a brick wall with this.

This is basic engineering little more advanced than wiring a switch which you so vehemently berated a visitor for and effectively accused of being a moron. Is this the ethos we wish for recording.org? I think not especially not from a mod. This type of abuse and misinformation is much more associated with gearslutz and is exactly why I have never bothered to post there and very very rarely even look at.

Ok...Changed the battery in my ohmeter and voila, I had a short between pin 2 and ground (told you I didn't solder it). Reworked the entire interior solder job and off to the ballpark I went. (Our boys kicked booty 48-0) Unfortunately I didn't take the time to pin it out and when I got to the booth, plugged it in and it worked, both with the button depressed and without. So, now I am at the opposite end. Might have damaged something internal to the switch and will check it out this afternoon. I'm getting there.

Ok..Now it all pins out ok but it doesn't mute the mic. When the button is not depressed, I have continuity between pins 2 and 3, effectively shorting pins 2 and 3 together. When I push the button, I only have continuity between the ends of pins 2 to 2 and 3 to 3 which if I've followed the directions here should be the only time the mic works. Unfortunately as stated in my previous post, the mic works, with approximately the same volume of output regardless of switch position. Any more ideas?

This one is running all the way....

Your report indicates that switch box checks out as it should do. You will have to give us the details of your "6 channel mixer" and the cabling and connectors that you use to connect the PG48 mic to the switch box and the switch box to the mixer.

My mixer is a Yamaha EMX62m. I am trying to paste a photo of it here but not sure if I'll have any luck with that. I am plugged in to channel 4 (although I've tried 1, 2 and 3). Phantom Power is turned off. Tried this with both my Shure and my Beyer mics and there is no difference. Pinned out my cables which are OEM mic cables that came with both mics and a short 3' patch cable that goes from my switchbox to the mixer. I'm thinking about either soldering the SP switch inline on line 2 only or trying a DP switch and try to determine if noise assciated with switch operation is tolerable. In an on-air broadcast it would be undesirable, but for PA announcments at an outdoor High School football stadium it might be acceptable. Seems so simple...

To the best of my knowledge, those Yamaha units have perfectly respectable microphone input circuitry, so your problem is unlikely to be there. You didn't actually state this, but I'm assuming that the cables you talk about are both XLR(F) to XLR(M) but of different lengths, and that the microphones work as expected (including the built-in mute switch on the PG48) when you daisy-chain the cables without going through the switch box.

Yes yes and yes...I was beginning to doubt the theory of shorting the two together until again, I looked up other commercially available PTT switches. There is an Pro Co Model SAS1 made here in Michigan that shows the wiring diagram of "what's inside the box" and it is the exact same hook up as I have.

I think you should purchase the commercially available, pre-built unit. Then you can go bother them when it doesn't work, Mr. I have a basic electronic background of understanding, sir. It would work if you didn't get your switch contacts confused. When all else fails... wire everything wrong and backwards. Then it will work.

And that's a proper repair if you follow the original Neumann U87 schematic.
Mx. Remy Ann David

Boswell, Mr. Ease and other helpful folks on this forum. Thank you for your attempts to assist.

For Remy, go get yourself and adult toy and have intercourse with yourself.

I have multiple units all with fresh batteries... so no problem. My vintage 1980s Prelude 2, finally died. The others just don't rub me the right way. Sometimes it's fun to plug-in the 110 V units to the Crown DC 300 A while playing some dance music.

I always use Channel 5.1
Mx. Remy Ann David

I've just finished reading through 8 pages of argument about muting a phantom balanced mic.

Any phantom powered mic with a proper balanced output connected to any well balanced preamp input will not create any undue noise when shorting or un-shorting pins 2 and 3. There is typically a very small click, usually drowned out by the handling noise if the switch is XLR connector mounted like Neutrik or Switchcraft. If there is anything more than a very small click, either the mic or the preamp is not balanced very well.

Usually a loud pop is due to the 6.8K phantom supply resistors not being carefully matched; the pop is actually caused by the slight voltage change on the isolation caps equalizing when the switch is closed or opened. If the common mode rejection is really bad, shorting pins 2 and 3 can even still pass audio in some circumstances.

The importance of matching these resistors can't be stressed enough, as any mismatch also degrades common mode noise rejection on the mic line. This is a common problem on many cheap powered mixers like Behringer, Peavey, and yes, even Yamaha.

To me this has nothing anymore to deal with phantom powering a microphone for switching situation. This is now about just trying to figure out the inner workings of any SPST or DPST or DPDT type switch. Testing for continuity is important here but get rid of your wiring all together and spend 30 minutes just testing continuity on the switch w/ out anything soldered to the lugs. That is how it is done.

So pin 2 & 3 are inverted signals (nothing to do with phantom power in this instance of the thread now) and connecting the two together will cancel out the signal. Very basic. What can help this thread is not talking about the XLR inputs on your PA system but more about the actual switch. What switch are you using? Where did you buy it? What is the model number? Can I see a picture of this switch and your whole setup at this point?

Why not just get a powered mixer that has a mute button? I mean this thread needs some happy outcome so let's get it done! Or my name aint Nathan Arizona!!!
diddlydoo(y)

Sure the PA might be inexpensive and simple but it is still balanced inputs. Although Byacey makes for strong point on his last post there... thumb

Oh and if it involves phantom power...
 
Needs to be in an enclosure w/ the pin1 grounded to this enclosure...

Edit: oh yeha can we order Remy an RC Snubber for her vintage Prelude 2? It has been making a clicking or popping noise when you push her "Push to talk" buttons!! lol All the best to this thread it is truly epic!! facepalm

byacey, post: 395409 wrote: I've just finished reading through 8 pages of argument about muting a phantom balanced mic.

Any phantom powered mic with a proper balanced output connected to any well balanced preamp input will not create any undue noise when shorting or un-shorting pins 2 and 3. There is typically a very small click, usually drowned out by the handling noise if the switch is XLR connector mounted like Neutrik or Switchcraft. If there is anything more than a very small click, either the mic or the preamp is not balanced very well.

Usually a loud pop is due to the 6.8K phantom supply resistors not being carefully matched; the pop is actually caused by the slight voltage change on the isolation caps equalizing when the switch is closed or opened. If the common mode rejection is really bad, shorting pins 2 and 3 can even still pass audio in some circumstances.

The importance of matching these resistors can't be stressed enough, as any mismatch also degrades common mode noise rejection on the mic line. This is a common problem on many cheap powered mixers like Behringer, Peavey, and yes, even Yamaha.

There are two separate issues here, which it sounds you are bundling together. The first is the topic subject: how to wire a switch to mute a microphone signal without it causing audible clicks or pops. The second is one you have brought up: common-mode rejection at the mic pre-amp input. Both of these can be affected by not only the pre-amp internal resistor matching but also by the output characteristics of the microphone in use.

Shorting the two signal pins together will always mute a properly balanced microphone. You have only to think of a dynamic mic, where there is no connection between the signal circuit and ground, and it will be evident. With capacitor (condenser) mics that need phantom power, the signal balancing will depend on the design of the microphone, and those with a transformer output may be better balanced than those that simply output separate + and - signals. Worst are the types that have a single-ended output and just an impedance-matching resistor in the other lead. However, all these types will mute fully when their outputs are connected togther. Only the single-ended output type will require some common-mode signal rejection at the pre-amplifier input to achieve full muting.

It leaves the question of whether the act of shorting and removing a short from the signal pins will cause an audible pop or click. This comes down to the difference in d.c. potential at the two signal pins in normal operation (switch open). Any potential difference will be due to differences in the ratios of resistances between the 48V supply internal to the pre-amp and the derived power rail in the microphone. The ratios are made up of the nominal 6K8 resistors in the pre-amp and whatever resistors the microphone designers have chosen to use in their particular product. While it is admirable to attempt to match the pre-amp's 6K8s to 0.1% or whatever, this degree of accuracy has little meaning if the microphone manufacturers have used only 2% resistors at their end of the chain. What would be needed is something like an additional 50 Ohm resistor in the + signal lead and a 100 Ohm trimpot in the - lead so that the d.c. difference between the signal leads can be zeroed for any given microphone and/or pre-amp combination. These two components could be incorporated in the box housing the muting switch, the trim being screwdriver-accessible from the outside. The trim need only be set once for a particular microphone feeding a particular mixer channel.

While the capacitor-short method linked to by Dr Gonz is neat, I personally don't like using electrolytic or tantalum capactors in low-level signal circuits such as this, especially where there is no significant polarizing voltage in the capacitor's designed polarity direction. In this application, the microphone will be muted for most the time but its mixer channel still open, so the low-frequency effects in the capacitor's electrolyte that tend to happen with low or non-existant polarizing voltage would result in rumbling noises through the PA.

The second schematic shown should eliminate any pop from switching, except the first time closing of the switch may still create a little pop due to the long time constant of the resistor and cap. Once the switch has been closed once, all should be well.

I've experienced this popping problem with dynamic mics as well, used on a balanced input having phantom power. Again the popping was due to the resistor mismatch as outlined in my previous post. It only takes a fraction of a millivolt difference between the phantom supply resistors, in conjunction with 40 to 60db of preamp gain to produce a big square wave at the speakers when the switch is opened or closed.

Boswell, post: 395463 wrote:
It leaves the question of whether the act of shorting and removing a short from the signal pins will cause an audible pop or click. This comes down to the difference in d.c. potential at the two signal pins in normal operation (switch open). Any potential difference will be due to differences in the ratios of resistances between the 48V supply internal to the pre-amp and the derived power rail in the microphone. The ratios are made up of the nominal 6K8 resistors in the pre-amp and whatever resistors the microphone designers have chosen to use in their particular product. While it is admirable to attempt to match the pre-amp's 6K8s to 0.1% or whatever, this degree of accuracy has little meaning if the microphone manufacturers have used only 2% resistors at their end of the chain. What would be needed is something like an additional 50 Ohm resistor in the + signal lead and a 100 Ohm trimpot in the - lead so that the d.c. difference between the signal leads can be zeroed for any given microphone and/or pre-amp combination. These two components could be incorporated in the box housing the muting switch, the trim being screwdriver-accessible from the outside. The trim need only be set once for a particular microphone feeding a particular mixer channel.

I would hope the manufacturer matches the 6.8K resistors as close as possible; not doing so lowers the maximum possible CMRR, regardless of what mic is used; of course, the bean counters at the factory probably have the last say in how good the rejection ratio will ultimately be, in an otherwise well designed preamp. It takes time and money to match those resistors.

For a permanent application where the mic is always used in the same input, the trimming scheme is a valid solution.

Any popping heard when switching a standard dynamic mic in a phantom-power environment cannot be due to resistor mismatch, as there is no phantom power current through the resistors and hence no voltage drop. The mic's coil resistance is in any case only a few tens of ohms, so shorting that out will remove the generated a.c. without any d.c. effects. All the manufacturer-fitted switches on dynamic mics that I know of operate this way, with some configurations being slightly different because of internal signal transformers.

When running live PA, I once had a problem with switch clicks on an announcer's dynamic mic feeding a mixer input that had phantom power enabled. I traced the trouble to a faulty XLR cable that had a high-resistance (MOhms) leak from one signal pin to screen, thus creating a small phantom current flow in one signal conductor and not the other.

Wow. This discussion is obviously out of my league... I'll keep reading though. FWIW, I still have not resolved the problem. To answer a few of the inquiries, the switch is a simple momentary contact, NO switch with two lugs. 3 dollar item from Radio Shack. There is continutity through the switch when it is not depressed, thus shorting the two wires together proportedly muting the mic which it does not. There may be another "leak" as someone mentioned, but when I get time, I am going to try a DP, ST switch to see if interrupting each of the two wires works better than shorting them together. Football season is over for now so I have until spring baseball to fiddle with it.

While you believe you are actually shorting pins 2 & 3 together and there is no muting, would say to me you are simply unbalancing the microphone. It's just dropping its impedance to near zero but not exactly 0 which still allows signal flow. Since pin 1, ground still provides for a 0 ohm reference. So what you really want is a 2 DPDT, momentary pushbutton. With this type pushbutton, it would be disconnecting the microphone and shorting the output of the microphone while shorting the input to the XLR, which should then solve the problem. Unfortunately, these are not cheap switches you find at Radio Shaft. These are specialty switches. Some that are completely soft and silent and others that click. You don't want the ones that click. So you want double disconnects and double shorts. You need a separation of church and state. Not something on the Republican docket. They want to ignore the Constitution while quoting it. So even Republicans cannot comprehend push to talk switches. LOL.

Go Obama! It's un-American not to vote.
Mx. Remy Ann David

A DPDT switch is fine when static in either of its two positions, but during activation it would leave the pre-amp inputs floating for the tens of milliseconds in which the contact changeover occurs. This in itself is going to cause a pop. Additionally, there's little point in shorting the microphone output when it's not connected to the pre-amp input.

A configuration that places a short across the microphone output without disconnecting anything is the only straightforward way to ensure that there is not a high-impedance changeover state.

Boswell, post: 395467 wrote: Any popping heard when switching a standard dynamic mic in a phantom-power environment cannot be due to resistor mismatch, as there is no phantom power current through the resistors and hence no voltage drop. The mic's coil resistance is in any case only a few tens of ohms, so shorting that out will remove the generated a.c. without any d.c. effects. All the manufacturer-fitted switches on dynamic mics that I know of operate this way, with some configurations being slightly different because of internal signal transformers.

When running live PA, I once had a problem with switch clicks on an announcer's dynamic mic feeding a mixer input that had phantom power enabled. I traced the trouble to a faulty XLR cable that had a high-resistance (MOhms) leak from one signal pin to screen, thus creating a small phantom current flow in one signal conductor and not the other.

I agree with you, it shouldn't happen, but none the less, it was making a slight click; not enough to be objectionable, but it was there. Most likely due to some small leakage as you mention. Shutting off the phantom power cured the click problem.

I'm not sure why Remy is introducing any association with pin 1 in the equation; in a floating output balanced dynamic mic (no center tap to pin 1), pin 1 has nothing to do with the signal except as an electrostatic shield for the signal conductors. You should be able to even lift the connection to pin 1 and still have the same muting action when shorting pin 2 and 3.

Using a DPDT shouldn't be necessary and will also tend to leave the preamp input unterminated, which will generally generate more Johnson noise and also be prone to external electrostatic noise pickup unless a short is also applied across pin 2 and 3 in the mute position. A single pole switch should more than adequately mute a mic, it's not like the cartridge coil is an infinite current source.

Girtski, what kind of mixer are you trying to use? This may offer some clue as to why you are experiencing problems.