PLEASE Never Stop doing these videos! After 30 years, you always teach me something that I didn't know, that I should have known, that makes perfect sense, but somehow I feel like I'm an apprentice. That's simultaneously humbling and exciting. And we're talking about Phantom Power of all things!
In all my years of Audio engineering (40 odd)I have never been able to grasp the concept of phantom power workings. This has explained it in the most simplistic form ever. Thank you so much and keep up the great work.
Thanks Dave. I really enjoyed this chat and demonstration. I've been running PA's and doing all sorts of sound for over 40 years and never really understood what was (technically) going on under the hood. In saying that, I always made sure that my pin to pin wiring was spot on and never had any major issues when running condensers with dynamics. Your bench top demonstrations are excellent, and show that the principles do not need a massive rig or console to explain. Keep up the discussion. Cheers ...
Thanks again , nice experiment. The loading of the second console un-powered phantom is due to the two , normally 6k8 , resistors used and as you showed us the phantom voltages combine when both on to share the microphone load. The idea of phantom power came from Telephone/Telegraph balanced circuits for either powering up repeater circuits or adding dc signalling to a balanced transmission line. Cheers Dude
Very brilliant explanation. Now, I will not be afraid that my house mixer would not damage the recording mixer even without isolating transformers! Thank you!
For the more technically curious, the actual 48v power supply in the mixer feed each channel separately through resistors, typically 20k ohms or more, so that any difference in the multiple supplies will be dissipated in a small amount of heat, and not damage the microphone or mixer. Even If one or more wires is shorted to ground, like using an unbalanced cable, it will not greatly affect other channels. The only possible damage would be if the microphone voice coil or transformer cannot handle the current. For example , a typical mixer feeds pins 2&3 through 47k ohm resistors, and a typical voice coupled is 200 ohms, so 48v would place about 0.2 volts across the microphone voice coil. It would not be healthy, and would push the coil against the end of its space. It would also generate some heat. The actual damage would depend on the specific microphone. Thanks for the excellent demonstration and keeping it simple.
I am sure that until now, under no circumstances have I seen an explanation as well structured about Phantom Power as this one, particularly on the question of the interconnection FOH /MONITOR mixers. Thanks, Dave. Keep up your good work. Greetings from Portugal
If I were on the road and had money for all the good things, i would chose you. From the few videos I’ve watched, I’m convinced you might very well be one of the best sound guys out there. That’s a big deal! There are many factors to running sound setups... and knowing you’ve got a person who is a Masterful tech is relaxing I’m sure. Thank you for yet another insightful video.
I gotta say when you pulled out the Neumann I'm like whaaaaaat. "If we're going to use something to test, let's use something expensive to do it with." Lol. You are hilarious my friend.
Dave , your videos are getting better and better. I just want you to know I really appreciate that you share your knowledge!. Thank you so much!. If you have time can you please review how to fix problems with getting pops or little shocks on the lips when they touch the mic and also noise or buzz from the monitors but not from the mains.
I'm an electrician industrial for 20 years plus and I love sound and computer networking as hobbies.of which I love doing. I recognised a lot of what Dave was saying,and learned a few new things too..
That's great - nice, simple and clear explanation and demonstrations. Thanks. Another 'danger' case is linking an output of one console to an input of another. I had a repair case when several balanced line outs of a large expensive Soundcraft console had been destroyed due to being connected to the balanced inputs of another console that had phantom power active on those inputs. Some outputs may be protected against damage being caused this way - but for sure not all.
Interesting. Phantom is so low of a current and should not hurt outputs. That said, I have run into situations where activating phantom caused the outputs to distort. Not personally burned outputs though.
@@DaveRat The pleasure is mine. I've been involved in sound in some capacity since 1996 but in the film industry since 2001 as a boom operator. Completely different world from yours but your knowledge and teachings have helped round out my sound knowledge.
Not sure if anybody else mentioned it in the comments or maybe you followed up Dave but people often forget that if you are using a splitter box with out transformers but does have ground lifts for one or two of three splits phantom power should come from the split that the ground lift does not lift. When the ground gets lifted it breaks the phantom circuit.
EXCELLENT video as always! My only comment is that this only works IF everything is properly wired and undamaged. You did touch on what happens if a dynamic mic is in the mix and an unbalanced cable is used...BUT what about the possibility of damaging a console's input or the output on a piece of equipment with improperly wired cables, a damaged cable, or some other issue combined with phantom power? I've just been burned by this one too many times...especially when tying into someone else's gear. If it's all your gear, and all properly maintained, perfect! I still much prefer an active or transformer split for some isolation, but that's just me...
Phantom power should be safe for all pro gear regardless of being wired properly. It is limited by 6800 ohm resistors and gear designers should and almost always take into account the potential existence of phantom Computers, semi pro, super cheap and home hifi gear? Not so much, that will often get cooked by ohantom
Great explanation of the mysterious phantom power! Also like that you explained that AC and DC can both flow on the same pair of wires. Telephones, old Lionel trains and cable TV are some other examples that take advantage of this too :)
Thanks for taking the time and trouble to do these videos. I learned some things from this one in particular. Even an ol' sound dog like me isn't afraid to admit that I can still learn stuff! Not that it's doing me any good at the moment with nowhere to apply my knowledge, but I remain hopeful.
Many of us share your disappointment from not being able to do live events, Carl. Just hang in there and eventually we'll all be back in action, and probably appreciating what we get to do even more than ever thanks to a shift in perspective from this weird time. Stay strong. 💪🤘🖖
Great video! There's a lot of information here I've kind of put together over time (sometimes from watching you), but it's great having it all together and verified.
Great demonstrations thank you! Dave over at EEVBlog invited Doug Ford (from Rode Mics) to explain phantom power and a lot of other microphone design considerations on the EEVBlog channel here on TH-cam. I highly recommend them. (Phantom power is episode #616.)
Two things : Red should be pin 2 (hot) ? And blue pin 3 (Cold) The condenser mic is a Neumann kms105 not a sennheiser kms105😉 And I like your videos Thanks🙏🏼
Nice bass test in the end :D Great info, I guess someone who is an electric engineer would have known this already, but developing an intuitive understanding of electricity is Incredibly hard for some (like me) :)
Hey Dave, super informative, I learned a lot. What about ribbon mics? I know it's more of a studio mic choice but I heard ribbons can be damaged by 48 volts. What's your experience with this and why does it damage a ribbon?
Ribbin mics are delicate and properly wired cables should not damage them. That said, one error can destroy them. Royer ribbons are phantom powered which protect the ribbons and they need phantom
As always, another excellent video, Dave. You mentioned having first generation (1970's) AKG C-451's that would run on anything from 9 - 52 Volts DC phantom power. The wide range of power options allowed them to be used with field recorders or other battery operated devices or just any console that used a different voltage because there was no agreed upon standard back then. But one less common mic that many engineers are not familiar with is the AKG C-452 which used the same modular head/capsule system but it could _only_ run on 48 Volt phantom power because it was designed and sold shortly after 48 Volts became internationally standardized among manufacturers (1981?). Allegedly the 452 with its modified 48 volts only circuit has a lower noise floor than the 451 but I honestly don't know if that's true.
I always love your videos. You always break stuff down and show it, instead of just talk about it. I appreciate that. I watch videos of yours on stuff I already know and still enjoy them and pick stuff up. Quick question though, I didn't think DC could pass through a transformer. Isn't that one of a transformers (isolation transformer) uses is to filter DC out?
Not sure of the specific part you are referring without re watching the vid, but... There is a way to pass a DC voltage through a transforme and have it function correctly for ac by tying the centertaps of the primary and secondary together if one leg of the DC was applied to both sides of the primary in relation to ground. The DC would show up on both sides of the secondary in relation to ground. This is how phantom power can pass through transformers designed to pass phantom work
@@DaveRat Well I learned something new. I didn't think it was possible to pass DC. Thanks for the clarification. You're the man. Love your work and passion for audio. I share it.
Thanks Dave! Great video! I have only one question, if you would want to create 96V by running two consoles in series (20:30), how would you do it? would you just revers pins 1 and 2 on one console, or am I missing something? Thanks
It would be tough or not easily possible. You would connect pins 2 and 3 or pin 2 or 3 to the ground pin 1 of the other console and then, if at least one console was battery powered or not grounded in any way, you could see 96 volts between the pin 1 of console 1 and puns 2 and 3 of console 2. Basically you would need to wire the phantom powers in series. But if the pin 1 grounds of both consoles were referenced to each other then the 2nd console would just short the 1st console phantom to ground. That would not hurt anything but you would just get 48v
That's an interesting question. Since phantom power is 48 volts on both pins two and three and a polarity reverse only switches to with three polarity reverse makes no impact on phantom power. There are several ways to reverse polarity either by swapping pin 2 and 3 or as consoles normally do after the line is unbalanced putting a polarity reverse opamp or circuit there. Either way phantom shows up on both pin 2 and 3 If you have the time check out my videos on phantom power you may find them interesting I did one specifically on powering mics with multiple consoles
hi Dave - thanks for the video. Quick question--when you pass the phantom thru a splitter snake that has transformers on it where you can lift the grounds and all--how does that affect the consoles which deliver phantom? for example, I run a couple different splitters--whirlwind and ramlatch splitters and my to-console splits are 1 direct and 2 isolated. I tend to isolate the house desk from the monitor desk feed and make monitors run phantom. But on occasion, which I haven't been able to figure out, I have to apply phantom from the house desk in order to get a direct box to see power. If my house feed is isolated - that shouldn't work or be needed...but it does. Any thoughts on what is happening here within the transformers or the splits that I am not understanding? I feel like I am missing something obvious..been doing this 40 years but this when it happens (and it is not often) it baffles me. I've tried to figure it out - it isn't only on one llne/channel or with one direct box or from one channel on the split where a wire might be crossed. Any suggestions how to figure this out or track it down? Everything works so I have been hesitant to argue with it - but am I missing something here? Please tell me I am not getting senile.. :) thx!
We just bought a set of drum microphones for a church. Is it safe to use another mixer just for the drum mics for 48v (both the dynamic and OH condenser mics) and use a send for the snake, traveling to the main house console? Otherwise, I'll have to check the wirings of my dynamic mics and xlr cables one by one if we'll gonna be using a single console where both the drum mics, singers instruments will be plugged in. Thanks in advance Dave! Your videos are always helpful!
Yes, all good with using a drum sub mixer and also, with the SoundTools XLR Sniffer/Sender (I designed it) you can test all your lines in a few minutes or less. Just turn on phantom and plug in the sniffer to each channel on the snake and it will tell ya good or no good. Probably worth having one. th-cam.com/video/bG77DLOTPsQ/w-d-xo.html
I love the question! Tell ya what, if you join and you're not happy and they don't respond all your money I'll personally send you a check for whatever they don't refund
I'm a total novice about this topic but I have a question about using drum mics. The typical kit comes with various dynamic mics for close mics on the drum and two overhead pencil condenser mics that require phantom power. Obviously, when using one mixer, you have to turn on the phantom power for the condenser mics but that means it's on for the dynamic mics too. It sounds like you're saying this is ok as long as the cables are good. I was wondering this is the normal, expected way to use these drum mic kits. I haven't found any source that addresses this specific issue. Thank you.
Mosicers allow 6urn8ng on phantom on each channel seperately. That said, if phantom was dangerous to any mic, that would be a huge problem. Phantom is safe for all mics with properly wired cables and phantom is so low power almost no mics can be damaged by it though there are some older ribbon mics that can be damaged by wind, dropping, blowing into them and potentially miswired phantom. Don't worry, you won't ever encounter these or any mic that can be damaged by phantom unless if you break into the vintage mic section of a recording studio.
Chiming in late. I've been watching your videos for several years off and on and they're all great and informative. Regarding this video on phantom supplies, there is one legit issue with not using phantom on inputs not requiring phantom. Such as wireless microphone receivers. As you mentioned, capacitors are used to block DC, protecting a mixer's active input circuitry as well as active devices connected. And in a perfect world this works well. However should a phantom powered microphone, wireless receiver (or any direct connected device with active as opposed to passive outputs) be unplugged or plugged in, the voltage change on the capacitors will cause the capacitors to briefly pass the voltage onto the internal circuitry of the mixer or other devices. This can cause a signal spike to be heard in the sound system as a pop. it can also damage microphones or active devices connected. Rule x; never plug or unplug microphones or devices into a mixer, stage box or sound system while phantom voltage is active. Make all connections first then activate phantom. And then there's the occasional bad mic cable causing loud pops in the sound.
Another home run Dave! Stuff we can use. I would assume that this is a moot point with linked digital consoles -- only one (or a stage box) can actually generate +48V.
@@DaveRat I hope you didn't think I was being sarcastic, I really meant it was useful. I was just thinking about the digital realm and realizing that it's a different situation. Thanks for all you do!
Hi, Dave Rat. I was taught BEFORE you plug in a mic with phantom power, you first plug the mic in WITHOUT phantom power engaged, then engage it. and then when it's time to tear-down, you turn OFF phantom power from your console or whatever source is driving the phantom power, then wait about 1 min (for the voltage to go away from the mic / cable) and THEN it's safe to unplug the mic from the xlr. is that wrong?
@@DaveRat I had no idea, thanks for that info! It's been 20 years though for me of doing it this way that I just have to keep on with that program of the way I do it. I was literally cringing when you just plugged in that $3,000.00+ U-89 mic! .... and then unplugged (with the method I was referring to above). yikes! but I hear you, it doesn't bother the mic and as long as your channel is muted while engaging, plugging in / out, you won't experience the pop noises.
Hey Dave, what is the frequency sweep you use on you intro / outros? Extremely nice for a quick Full range to Sub balance method. It's 4 times faster to just load a video from you before I get started on a session than to open a project setup just for monitor balancing. I bet that's not the compliment you were expecting out of this video, but it occurs to me you might could make a video based around giving the community a common reference point for dialing in drive rack based monitor systems. Although I wield a 7.1 Mastering system, a mono tone set followed by a stereo tone set could help those who either do not have hardware on hand or the know-how to setup a DAW project to do that. I mostly use my system for watching Blu-rays and Prime, sad kinda, but also blows every public movie theater away, also real content helps to hear/feel how closely the system represents other systems my content will play on.
Very cool. The sub outro tine actually comes from a subwoofer test tone sequence I use for testing subwoofers. On the paid members side there is an extended video as well as a link to a wave file. It is 20hz to 100hz
Dave, could you do a comparison between active and passive DI boxes? We use both and can't seem to tell a huge difference on the different instruments we use them on. And also, maybe compare against an instrument amp XLR direct out? Thanks!
Hi Dave, i have a very basic question - if i have a mixer with just one button to turn off phantom power on the whole mixer and i have a device that outputs line level over xlr, should i put a di-box between the mixer and the line level device to prevent damage or can i just connect the line level device directly to the xlr inputs of the mixer that has phantom power turned on?
It won't damage but some output circuits don't perform well when phantom is applied. I would just test and listen to the device with and without phantom. If you don't hear a difference, then I would not worry about it
Hey Dave, long-time fan and love the videos! Just to calm the nerves of those in our shop - with what you stated about the current being low, can I assume that if I have wireless mic receivers receiving phantom power that there's not much cause for concern? Thanks!
Great video Dave ...often contemplated these things. Do you subscribe to having phantom both ends of the snake then for voltage stabilities sake and have you ever found a change in practical sound from any condenser that has a phantom fluctuate from 48v to as low as you’ve measured. The one thing I’ve missed is your opinion on what some of these experiments show you about the quality of the sound the different environments make. Was especially interested in your cascading channel analogue vs digital mixer experiments ...there were some raised eyebrows but nothing on the audio aesthetics. Nice one for the videos mate ...what else does one do when there’s nothing to mix
Cool cool. Having the added phantom voltage should at best, just offer slightly more headroom as well as redundancy. The main point is that it does not hurt anything. And ever so slightly could help.
Thank you so much for sharing your talents and experience with all of us. I have a question. I want to utilize 2 AT4033 large diaphragm condenser mics in my acoustic trio. I also love the sound of our Meinl slap top cajon with passive pickups connected directly. Im told by percussion dealers that phantom power will damage it and our small Bose digital mixer doesnt have individual channel control of phantom power. How can I protect the cajon? Will the low Z output of any passive direct box isolate and serve the purpose? Do I need a specific device? Thanks again!
Yes, the output of a direct box will block phantom. Or use and isolation transformer. Or make a special xlr cable that has 100uf capacitors on pin 2 and pin 3. Phantom won't go through a capacitor.
@@DaveRat Thank you so much! Your approach and egoless attitude are rare and so refreshing in this business. You should write a book or a series. I'm sure they'd be VALUABLE go to resources for all of us. Your knowledge and experience needs to be preserved. Thank you!
Thanks for teaching me what a balanced cable is. A question... If the two different consoles are at slightly different voltages, theory tells me would that cause some current flow between the two units. Have you any idea how the two different power supplies cope with that? Obviously, no magic smoke is released! Thanks!
All input and output voltages are either floating or references to ground. Inputs look at the differential between the two hots on balanced lines and the diff between hot and ground on unbalanced. Outputs create the same things. As long at the gear is either isolated through a transformer or other method like being battery powered or references to the same ground as the other gear, all good. Differing ground potentials on non isolated gear causes issues
The one with the higher voltage will be providing most of the current. The internal 6.8K resistors help out with current sharing, so the difference will be small.
Question please. I have a splitter that itself provides phantom for each channel if needed. In your scenario above, I am assuming that a voltage drop occurs because I have two consoles FOH and monitor not turned on for phantom as I have been relying solely on the splitter source for the power. I don't use enough condensers that I think it would cause too far a drop, but with that scenario, should I be keeping it as I have it or should I have phantom on both channels from both boards as well as the phantom on the splitter. My boards allow phantom to be selected for each channel needed vs powering the entire board. Thanks for the explanation, it makes sense, I just never gave it a thought before 🙂
I can see that the cats stagebox seems to pass Phantom power. I wanted to know if that same stagebox would be able to pass phantom power across a cat6 cable going into the snake?
Good timing on this one for me Dave. I have a Focusrite 18i20 interface, I run a pair of TRS to XLR cables from its outputs into a snake or inputs on a mixer. I’ve been worried about somebody sending me phantom power to the interface outputs. I doubt the interface outputs are transformer isolated, so because there’s no power on the tip or ring, I should be ok? I’d only have a problem if I was running 1/4” to XLR unbalanced cables, correct? I was thinking about buying or making a two channel transformer isolation box to safeguard against this, but if I run balanced cables I’m ok, unless there’s a problem with the snake?
Avoid running phantom to electronic inputs. Capacitor iso will solve but often electronic inputs don't like the 48 v DC offset that phantom sends and will act strangely
You can test for isolation by checking continuity of the grounds for both the input and the output --- if there is no continuity then they are isolated.
Fantastic vid as usual Dave! Would love to hear your recommendations for study material regarding Power in the live environment. I know i'm not up to scratch on power, and with Universities putting out more engineers, I feel like power is the least understood part of this job. Hope you're in good health! ALSO WHO PUTS SUB ON THE OUTRO OF THE VIDEO?
I don't have good reference for live event power, definitely would be a good thing to find. Lots of stuff to know as well as conflicting regulations depending on country and portable versus fixed wiring.
Hi Dave. Thanks for the video! I do not fully understand how everything (phantom)power works, so I have one question. When connecting the two consoles, why doesn’t the phantom power of console 1 hurt the pre amps from console 2? If I am correct, the cables are directly attached to both consoles. Does the XLR split prevent that from happening, or is it completely fine for the pre amps to receive +48 from the other console? Thanks in advance!
All consoles and most if not all mics are designed such that phantom power will not hurt them. Also, phantom power, is very very low power, typically way less than .5 watts per leg. For comparison, a USB -C cable can deliver up to 100W. So USB-C can be 200 x as powerful and damaging as phantom power. Even though phantom is 48v, it is severely current limited so as soon as it sees even the slightest load, it drops in voltage very quickly. It would take a few weeks to charge you phone with phantom power
Dave, Is there ever any chance of having too many consoles running phantom power in parallel that could possibly cause injury from too much accumulated current due to a faulty snake system?
Two seperate issues. Faulty snake can give annoying shocks to the lips and hurt some mics with phantom. Paralleling 3, 4 or 5 consoles w phantom still has way way less power than a USB
Agreed, power is so low that it is not possible to injure someone. But I have been called out to fix a a system where a gal was getting shocked and fount phantom power and a faulty snake ground was putting 48v on her lips when she sang and held her guitar.
Enjoyed the explanation, another question popped up - what would happen if the phantom power was on from both consoles and an unbalanced/shorted (pin1 to pin2) cable was used? Thanks again.
The unbalanced cable would short out the phantom on pin 2 supplying 1/2 the current to a condenser mic but the second console would replace the missing current, dynamic mics would see double the current across the voice coil or internal transformer. The console would be fine as phantom is designed to be ok with being shorted
I’m wondering what happens when you split the mic cables and have two desks both supplying phantom power ? Ps not finished video yet :-) Haha just watched the rest 👍🏻
I wonder if there is any microphone response difference if 3 or more consoles drag down the voltage enough? Any pro OB set up I've seen always used an active 3rd split anyway. Would having 3 phantom switches on 1channel triple the current then?
It should not and is easy to test, just listen or measure the output of one console while plugging and unplugging the other console. Typically a console input will be like 10,000 ohms or so and a mic output will be 200 ohms or so. So, you can drive several consoles with very minimal impact on the mic output level and loading of the mic.
Great question. Phantom is supplied from the console to the output XLR of the DI. Where a phantom DI will grab the phantom to power it's internal circuits. The ground lift on a DI is breaking the ground connection from the input ground to the output pin 1. So the input signal is grabbed by the di and outputted on pins 2 and 3 of the XLR and the input is not connected to the output ground. The isolation of the input to the output can be done with electronics or with a transformer then boosted by electronics.
A lot of DIs don't fully disconnect when the ground lift is engaged. Pin one is still connected via a parallel 100 ohm resistor and 0.1uF capacitor. This allows enough current to pass to power an active DI but is enough resistance to reduce earth loops.
Typically a differing phase is not an issue. Its when the ground for mons and FOH are different and not tied back to the same place that issues arise. Since neutral is tied to ground somewhere in most, if not all, power systems, loads on the neutral can drag it off of zero volts and possibly drag the ground off of zero volts. Or if there is gear that somehow causes the ground to not be zero volts, that can cause issues if the ground at FOH is differing in voltage to the ground at mons. With digital snakes, this is less of an issue and usually a non issue as long as the ground offset voltages are small. With analog snakes and interconnects, even very small offsets in voltage between the ground at FOH and mons can cause hum and buzz issues. Large ground voltage offsets can be dangerous or deadly.
Hi Dave. I remember years back when using analog consoles and hardwire split snakes, if you had phantom coming from both FOH & Monitor consoles, you would almost always get a buzz. Was this another issue? You mentioned using multiple phantom sources as a practice.
Interesting, for years I toured with hardwired splits, avoiding the sound differentials cause by transformers. And used dual phantom as a norm without issues.
nice topic....i have been wonding about it quite a while ago and i didnt found answer, thanks for that another question would be, what will happen if you feed line output signal from one cosole to the phantom powered input of another console?
Sending phantom to electronic outputs can give varied and often undesirable results. Due to the wide diversity of output circuit designs, there is no rule to whether it will have a negative impact, other than avoid it. Phantom can be blocked with a pair of capacitors inline on pins 2 and 3 of an XLR or using an iso transformer
Can the phantom power ever damage either of the consoles providing it if the split is passive/not transformer isolated? I would assume the power would travel back up the split into each other. i.e. monitor and FoH console both going into a passive split - I'm just wondering how people get away with passive splits in this case
Consoles that can create 0hatomenpower are immune to damage from phantom power. Most mic preamps are immune to phantom power impacting them. Transformers are immune Most input circuits are immune Some or many output circuits are not immune and will either act strangely or possible be damaged. Except: Mic output circuits are almost always ummune As a rule of thumb, phantom on input circuits, all good, phantom to out put circuits, not good. Passive splits is connecting multiple input circuits to a mic output
Thanks for the vid, could you help me a bit? I have an effect pedal with constant 24V phantom power, will it make any harm if i use it in a chain like this: Condenser mic --> external power supply with phantom power 48V --> effect pedal with constant 24V --> audio interface with turned off phantom power --> pc
Phantom power into balanced outputs should not hurt anything. I have seen some outputs don't like it and either distort or offer reduced output levels when phantom is went to them. Just try it. If it works and sounds ok, roll with it
It looked like plugging a mic into both mixers supplying power dropped the voltage less than with one supplying power. Seems like it can only be helpful having every console supplying it, especially if there's a lot of condenser mics being used. Which brings me to my main question, how many mics can one mixer supply power to? At what point do you need to add another supply?
Dave, I know this is wrong..... but, in case I need to use a XLR to mini jack (1/8"), should I use pin 2 and pin 3 only on XLR like hot and gnd, not using the pin 1? Thanks for all you do here, your videos are amazing!
Great explanation (as always on this channel)! I have one question though: If we have phantom power switched on at house and monitor consoles and the two consoles do not share the exact same ground (on the AC side, i.e. 120V or 230V depending on where you are); are maybe plugged into power outlets from different distribution boxes. In that case, we'd have some steady current on the (XLR) cables connecting the two consoles, specifically the ground wires, i.e., pin 1? To level out the difference in ground potential. Isn't this dangerous to the very thin mic cables?
Whether you supply phantom power or not the grounds of both consoles are connected together via the XLR lines unless specifically lifted. So any ground differential potentials that exist will exist regardless of whether phantom power is applied from one console both consoles or neither console
Is the ethercon breakout boxes wired T568A or T568B? Would this have something to do with why my ethercon system is not lining up 1 for 1? I wired my whole system T568B.
If you wanted to go from one mic into Y split cable and then onto 2 inputs of the same same mixer ( double patch type thing) Would it be the same as the 2 mixer set up? As I have often thought if doing this one apply 48V to one of the inputs.
Hi Dave, I have seen a lot of debate about allowing phantom power to feedback from a mixer into a Line6 Helix pedalboard's XLR line-outs. It sounds to me like the voltage on pins 2 & 3 shouldn't cause any problems if all of the equipment is working properly and the ground doesn't get involved and there are no shorts. Have you ever been a part of that conversation with any guitar players at a gig? I suppose there could be circuitry at the Helix end that would affect how the voltage is "seen" by the Helix? One of the suggestions was to use a voltage blocker in the XLR lines. Would it be a diode that would work like a check valve?
You can also just float pin 1 at the pedal if you're concerned. Many pieces of gear actually do that depending on their output circuit dont need the ground and the shield is still effective single ended (like most dynamic mics)
Dynamic mics don't need phantom, condenser mics usually do need it. Some ribbon mics need phantom and some do not. It's like a battery, some things like a radio, needs a battery, and something's like a hammer do not and and something's like an ice box can be powered to cool things and others just keep things cool and don't need power
So if I inject phantom power to a mic and use the one side of the xlr output of the mic to the unbalance mic input of a DSLR, ill kill it with 18v in the audio path?
Oh my, yeah, it gets complex but yes, phantom power is not typically compatible with unbalanced. Using a small transformer to convert to unbalanced while phantom and the mic are on the balanced side of the traslnsformer is good.
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PLEASE Never Stop doing these videos!
After 30 years, you always teach me something that I didn't know, that I should have known, that makes perfect sense, but somehow I feel like I'm an apprentice. That's simultaneously humbling and exciting. And we're talking about Phantom Power of all things!
Awesome, thank you!
In all my years of Audio engineering (40 odd)I have never been able to grasp the concept of phantom power workings. This has explained it in the most simplistic form ever. Thank you so much and keep up the great work.
So cool and thank you! Honored
Thanks Dave. I really enjoyed this chat and demonstration. I've been running PA's and doing all sorts of sound for over 40 years and never really understood what was (technically) going on under the hood. In saying that, I always made sure that my pin to pin wiring was spot on and never had any major issues when running condensers with dynamics. Your bench top demonstrations are excellent, and show that the principles do not need a massive rig or console to explain. Keep up the discussion. Cheers ...
Thank you Perry
This is great! Thank you for this video. When I saw the two 9v batteries in parallel, I knew exactly what’s going on.
👍⚡👍
Best explanation of this ever. Thank you
Thank you, big smile
Thanks again , nice experiment. The loading of the second console un-powered phantom is due to the two , normally 6k8 , resistors used and as you showed us the phantom voltages combine when both on to share the microphone load. The idea of phantom power came from Telephone/Telegraph balanced circuits for either powering up repeater circuits or adding dc signalling to a balanced transmission line. Cheers Dude
Awesome. Thank you Dave
nice! the more I watch your videos, the more I realize how important it is to get a practical understanding of electrical connections and signal flow.
So cool and yes and thank you!
You rock. The deep dive, your personality, and the outro with low freq sweep etc., I love it!
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Great video Dave. You really made it easy for me to understand how phantom power works, especially with the drawings. Cheers for that.
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Really cool video. Appreciate the intentional fault to show the mic coil popping.
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i can't get enough of your videos. does the audio engineering rabbit hole get any deeper than this!
Ha! Awesome!
Very brilliant explanation. Now, I will not be afraid that my house mixer would not damage the recording mixer even without isolating transformers! Thank you!
Excellent
Thanks so much Dave. Love these videos, they're very informative and you're an inspiration to everyone in the industry.
Awesome and thank
For the more technically curious, the actual 48v power supply in the mixer feed each channel separately through resistors, typically 20k ohms or more, so that any difference in the multiple supplies will be dissipated in a small amount of heat, and not damage the microphone or mixer. Even If one or more wires is shorted to ground, like using an unbalanced cable, it will not greatly affect other channels. The only possible damage would be if the microphone voice coil or transformer cannot handle the current. For example , a typical mixer feeds pins 2&3 through 47k ohm resistors, and a typical voice coupled is 200 ohms, so 48v would place about 0.2 volts across the microphone voice coil. It would not be healthy, and would push the coil against the end of its space. It would also generate some heat. The actual damage would depend on the specific microphone.
Thanks for the excellent demonstration and keeping it simple.
Agreed and I believe the phantom power spec calls for 6.8k ohm matched pair resistors
@@DaveRat thanks, I couldn’t remember off the top of my head.
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I am sure that until now, under no circumstances have I seen an explanation as well structured about Phantom Power as this one, particularly on the question of the interconnection FOH /MONITOR mixers.
Thanks, Dave.
Keep up your good work.
Greetings from Portugal
Awesome, thank you
If I were on the road and had money for all the good things, i would chose you. From the few videos I’ve watched, I’m convinced you might very well be one of the best sound guys out there. That’s a big deal! There are many factors to running sound setups... and knowing you’ve got a person who is a Masterful tech is relaxing I’m sure. Thank you for yet another insightful video.
Hell yeah and thank you!
I gotta say when you pulled out the Neumann I'm like whaaaaaat.
"If we're going to use something to test, let's use something expensive to do it with."
Lol. You are hilarious my friend.
Fun!!
Dave , your videos are getting better and better. I just want you to know I really appreciate that you share your knowledge!. Thank you so much!.
If you have time can you please review how to fix problems with getting pops or little shocks on the lips when they touch the mic and also noise or buzz from the monitors but not from the mains.
Yeah, I can do a pop shock vid
I'm an electrician industrial for 20 years plus and I love sound and computer networking as hobbies.of which I love doing.
I recognised a lot of what Dave was saying,and learned a few new things too..
Awesome!
HI i like how in-depth you go on explaining stuff and showing details.
Thank you!
That's great - nice, simple and clear explanation and demonstrations. Thanks. Another 'danger' case is linking an output of one console to an input of another. I had a repair case when several balanced line outs of a large expensive Soundcraft console had been destroyed due to being connected to the balanced inputs of another console that had phantom power active on those inputs. Some outputs may be protected against damage being caused this way - but for sure not all.
Interesting. Phantom is so low of a current and should not hurt outputs. That said, I have run into situations where activating phantom caused the outputs to distort. Not personally burned outputs though.
I love your demos Dave. Your channel is one I recommend very often thru mine.
Thank you!
@@DaveRat The pleasure is mine. I've been involved in sound in some capacity since 1996 but in the film industry since 2001 as a boom operator. Completely different world from yours but your knowledge and teachings have helped round out my sound knowledge.
@@SoundSpeeds
Not sure if anybody else mentioned it in the comments or maybe you followed up Dave but people often forget that if you are using a splitter box with out transformers but does have ground lifts for one or two of three splits phantom power should come from the split that the ground lift does not lift. When the ground gets lifted it breaks the phantom circuit.
this is absolutely correct phantom will not pass with the ground lifts also running phantom to a ground lifted split will not hurt anything
EXCELLENT video as always!
My only comment is that this only works IF everything is properly wired and undamaged. You did touch on what happens if a dynamic mic is in the mix and an unbalanced cable is used...BUT what about the possibility of damaging a console's input or the output on a piece of equipment with improperly wired cables, a damaged cable, or some other issue combined with phantom power? I've just been burned by this one too many times...especially when tying into someone else's gear. If it's all your gear, and all properly maintained, perfect! I still much prefer an active or transformer split for some isolation, but that's just me...
Phantom power should be safe for all pro gear regardless of being wired properly. It is limited by 6800 ohm resistors and gear designers should and almost always take into account the potential existence of phantom
Computers, semi pro, super cheap and home hifi gear? Not so much, that will often get cooked by ohantom
Great explanation of the mysterious phantom power! Also like that you explained that AC and DC can both flow on the same pair of wires. Telephones, old Lionel trains and cable TV are some other examples that take advantage of this too :)
Awesome!
Thanks for taking the time and trouble to do these videos. I learned some things from this one in particular. Even an ol' sound dog like me isn't afraid to admit that I can still learn stuff! Not that it's doing me any good at the moment with nowhere to apply my knowledge, but I remain hopeful.
Very cool and thank you!
Many of us share your disappointment from not being able to do live events, Carl. Just hang in there and eventually we'll all be back in action, and probably appreciating what we get to do even more than ever thanks to a shift in perspective from this weird time. Stay strong. 💪🤘🖖
Amazing to get these graduate level info packets from the icon himself.
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Brilliantly thought out and presented.
Awesome and thank you
Great video! There's a lot of information here I've kind of put together over time (sometimes from watching you), but it's great having it all together and verified.
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Super explanation. simple and easy
Thank you 🙂
A most brilliant video.a superb production.
Thank you Stephen!
Great demonstrations thank you! Dave over at EEVBlog invited Doug Ford (from Rode Mics) to explain phantom power and a lot of other microphone design considerations on the EEVBlog channel here on TH-cam. I highly recommend them. (Phantom power is episode #616.)
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I really enjoy your channel. I’m always learning! Thank you!
Thank you!
Great work as always, Dave!
Thank you!
Two things : Red should be pin 2 (hot) ? And blue pin 3 (Cold)
The condenser mic is a Neumann kms105 not a sennheiser kms105😉
And I like your videos
Thanks🙏🏼
Cool cool,
wow i was just talking about this last night over a beer/s... thanks for the video
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Thanks Dave for your continued work. Interesting to see the dual consoles experiment with a Neumann haha
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Nice bass test in the end :D Great info, I guess someone who is an electric engineer would have known this already, but developing an intuitive understanding of electricity is Incredibly hard for some (like me) :)
Fun stuff to learn!
Great video. I learned a lot and will implement using phantom from both mixers on a non transformer isolated splitter snake I have.
Excellent
Good info, looking forward to the zoom meeting tomorrow!
Thank you Neil and see you tomorrow!
Hey Dave, super informative, I learned a lot. What about ribbon mics? I know it's more of a studio mic choice but I heard ribbons can be damaged by 48 volts. What's your experience with this and why does it damage a ribbon?
Ribbin mics are delicate and properly wired cables should not damage them. That said, one error can destroy them. Royer ribbons are phantom powered which protect the ribbons and they need phantom
As always, another excellent video, Dave. You mentioned having first generation (1970's) AKG C-451's that would run on anything from 9 - 52 Volts DC phantom power. The wide range of power options allowed them to be used with field recorders or other battery operated devices or just any console that used a different voltage because there was no agreed upon standard back then. But one less common mic that many engineers are not familiar with is the AKG C-452 which used the same modular head/capsule system but it could _only_ run on 48 Volt phantom power because it was designed and sold shortly after 48 Volts became internationally standardized among manufacturers (1981?). Allegedly the 452 with its modified 48 volts only circuit has a lower noise floor than the 451 but I honestly don't know if that's true.
I remember the c452 maybe was the C452eb. Higher voltage also could help with max headroom.
@Phil Allison very interesting and thank you!
I always love your videos. You always break stuff down and show it, instead of just talk about it. I appreciate that. I watch videos of yours on stuff I already know and still enjoy them and pick stuff up. Quick question though, I didn't think DC could pass through a transformer. Isn't that one of a transformers (isolation transformer) uses is to filter DC out?
Not sure of the specific part you are referring without re watching the vid, but...
There is a way to pass a DC voltage through a transforme and have it function correctly for ac by tying the centertaps of the primary and secondary together
if one leg of the DC was applied to both sides of the primary in relation to ground. The DC would show up on both sides of the secondary in relation to ground.
This is how phantom power can pass through transformers designed to pass phantom work
@@DaveRat Well I learned something new. I didn't think it was possible to pass DC. Thanks for the clarification. You're the man. Love your work and passion for audio. I share it.
Awesome! Thank Aaron!
Awww...this is amazingly COOL !! Thank you Dave, its always pleasing watching your experiments. Keep doing this maestro and let us learn. Cheers \m/
Thank you Sunny!
Thanks Dave! Great video! I have only one question, if you would want to create 96V by running two consoles in series (20:30), how would you do it? would you just revers pins 1 and 2 on one console, or am I missing something? Thanks
It would be tough or not easily possible. You would connect pins 2 and 3 or pin 2 or 3 to the ground pin 1 of the other console and then, if at least one console was battery powered or not grounded in any way, you could see 96 volts between the pin 1 of console 1 and puns 2 and 3 of console 2.
Basically you would need to wire the phantom powers in series.
But if the pin 1 grounds of both consoles were referenced to each other then the 2nd console would just short the 1st console phantom to ground.
That would not hurt anything but you would just get 48v
Great episode 👏 what would happen if both desks had phantom power on but one desk had phase reverse on ?
That's an interesting question. Since phantom power is 48 volts on both pins two and three and a polarity reverse only switches to with three polarity reverse makes no impact on phantom power.
There are several ways to reverse polarity either by swapping pin 2 and 3 or as consoles normally do after the line is unbalanced putting a polarity reverse opamp or circuit there.
Either way phantom shows up on both pin 2 and 3
If you have the time check out my videos on phantom power you may find them interesting I did one specifically on powering mics with multiple consoles
hi Dave - thanks for the video. Quick question--when you pass the phantom thru a splitter snake that has transformers on it where you can lift the grounds and all--how does that affect the consoles which deliver phantom? for example, I run a couple different splitters--whirlwind and ramlatch splitters and my to-console splits are 1 direct and 2 isolated. I tend to isolate the house desk from the monitor desk feed and make monitors run phantom. But on occasion, which I haven't been able to figure out, I have to apply phantom from the house desk in order to get a direct box to see power. If my house feed is isolated - that shouldn't work or be needed...but it does. Any thoughts on what is happening here within the transformers or the splits that I am not understanding? I feel like I am missing something obvious..been doing this 40 years but this when it happens (and it is not often) it baffles me. I've tried to figure it out - it isn't only on one llne/channel or with one direct box or from one channel on the split where a wire might be crossed. Any suggestions how to figure this out or track it down? Everything works so I have been hesitant to argue with it - but am I missing something here? Please tell me I am not getting senile.. :) thx!
A transformer iso or split that has centertaps tied together on the inputs and outputs(s) will pass phantom.
@@DaveRat AHAH!! YES...ok thanks Dave. Sorry if this was a stupid question. Appreciate your response.
We just bought a set of drum microphones for a church. Is it safe to use another mixer just for the drum mics for 48v (both the dynamic and OH condenser mics) and use a send for the snake, traveling to the main house console?
Otherwise, I'll have to check the wirings of my dynamic mics and xlr cables one by one if we'll gonna be using a single console where both the drum mics, singers instruments will be plugged in.
Thanks in advance Dave! Your videos are always helpful!
Yes, all good with using a drum sub mixer and also, with the SoundTools XLR Sniffer/Sender (I designed it) you can test all your lines in a few minutes or less. Just turn on phantom and plug in the sniffer to each channel on the snake and it will tell ya good or no good. Probably worth having one.
th-cam.com/video/bG77DLOTPsQ/w-d-xo.html
Great explanation! Thank you for the time you put into these videos!
I love the question! Tell ya what, if you join and you're not happy and they don't respond all your money I'll personally send you a check for whatever they don't refund
High quality artistic skills!! Made my day! And I left TH-cam more informed again.. thanks dave.. ps. Do you have a license?
Licence?
@@DaveRat for those guns! Been working out more in lockdown?
@@lerrynhawke3375 ha! Surfing everyday and made my day!
I'm a total novice about this topic but I have a question about using drum mics. The typical kit comes with various dynamic mics for close mics on the drum and two overhead pencil condenser mics that require phantom power. Obviously, when using one mixer, you have to turn on the phantom power for the condenser mics but that means it's on for the dynamic mics too. It sounds like you're saying this is ok as long as the cables are good. I was wondering this is the normal, expected way to use these drum mic kits. I haven't found any source that addresses this specific issue. Thank you.
Mosicers allow 6urn8ng on phantom on each channel seperately. That said, if phantom was dangerous to any mic, that would be a huge problem.
Phantom is safe for all mics with properly wired cables and phantom is so low power almost no mics can be damaged by it though there are some older ribbon mics that can be damaged by wind, dropping, blowing into them and potentially miswired phantom.
Don't worry, you won't ever encounter these or any mic that can be damaged by phantom unless if you break into the vintage mic section of a recording studio.
Awesome explanation!
Awesome and thank you
You're a madman Dave! I love it! 😏🤘
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Thank you Dave, I loved that demo.
Thank you Ian
Chiming in late. I've been watching your videos for several years off and on and they're all great and informative. Regarding this video on phantom supplies, there is one legit issue with not using phantom on inputs not requiring phantom. Such as wireless microphone receivers. As you mentioned, capacitors are used to block DC, protecting a mixer's active input circuitry as well as active devices connected. And in a perfect world this works well. However should a phantom powered microphone, wireless receiver (or any direct connected device with active as opposed to passive outputs) be unplugged or plugged in, the voltage change on the capacitors will cause the capacitors to briefly pass the voltage onto the internal circuitry of the mixer or other devices. This can cause a signal spike to be heard in the sound system as a pop. it can also damage microphones or active devices connected. Rule x; never plug or unplug microphones or devices into a mixer, stage box or sound system while phantom voltage is active. Make all connections first then activate phantom. And then there's the occasional bad mic cable causing loud pops in the sound.
Totally agree. Phantom applied to electronic inputs or outputs that are not designed for phantom is a common issue. Great points!
Another home run Dave! Stuff we can use. I would assume that this is a moot point with linked digital consoles -- only one (or a stage box) can actually generate +48V.
Yes and no. Knowing how things work is not that important in optimum situations. And we all don't always deal with optimum
@@DaveRat I hope you didn't think I was being sarcastic, I really meant it was useful. I was just thinking about the digital realm and realizing that it's a different situation.
Thanks for all you do!
@@ToddWCorey1 no, all good and yes, with linked Digi, no need
Thanks Dave, that was brilliant that!
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Hi, Dave Rat. I was taught BEFORE you plug in a mic with phantom power, you first plug the mic in WITHOUT phantom power engaged, then engage it. and then when it's time to tear-down, you turn OFF phantom power from your console or whatever source is driving the phantom power, then wait about 1 min (for the voltage to go away from the mic / cable) and THEN it's safe to unplug the mic from the xlr. is that wrong?
Nothing wrong with that plan but as long as you are muted, the mic doesn't care if phantom gets turned on with a switch or by plugging in
@@DaveRat I had no idea, thanks for that info! It's been 20 years though for me of doing it this way that I just have to keep on with that program of the way I do it. I was literally cringing when you just plugged in that $3,000.00+ U-89 mic! .... and then unplugged (with the method I was referring to above). yikes! but I hear you, it doesn't bother the mic and as long as your channel is muted while engaging, plugging in / out, you won't experience the pop noises.
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Hey Dave, what is the frequency sweep you use on you intro / outros? Extremely nice for a quick Full range to Sub balance method. It's 4 times faster to just load a video from you before I get started on a session than to open a project setup just for monitor balancing. I bet that's not the compliment you were expecting out of this video, but it occurs to me you might could make a video based around giving the community a common reference point for dialing in drive rack based monitor systems. Although I wield a 7.1 Mastering system, a mono tone set followed by a stereo tone set could help those who either do not have hardware on hand or the know-how to setup a DAW project to do that. I mostly use my system for watching Blu-rays and Prime, sad kinda, but also blows every public movie theater away, also real content helps to hear/feel how closely the system represents other systems my content will play on.
Very cool. The sub outro tine actually comes from a subwoofer test tone sequence I use for testing subwoofers. On the paid members side there is an extended video as well as a link to a wave file.
It is 20hz to 100hz
Dave, could you do a comparison between active and passive DI boxes? We use both and can't seem to tell a huge difference on the different instruments we use them on. And also, maybe compare against an instrument amp XLR direct out? Thanks!
I will ponder some DI box demos
Hi Dave, i have a very basic question - if i have a mixer with just one button to turn off phantom power on the whole mixer and i have a device that outputs line level over xlr, should i put a di-box between the mixer and the line level device to prevent damage or can i just connect the line level device directly to the xlr inputs of the mixer that has phantom power turned on?
It won't damage but some output circuits don't perform well when phantom is applied. I would just test and listen to the device with and without phantom. If you don't hear a difference, then I would not worry about it
@@DaveRat Thank you for the quick response :)
Hey Dave, thanks for this ! greetings from Berlin
Greetings Curtis!
Hey Dave, long-time fan and love the videos! Just to calm the nerves of those in our shop - with what you stated about the current being low, can I assume that if I have wireless mic receivers receiving phantom power that there's not much cause for concern? Thanks!
It won't hurt them, that said, some electronic outputs act strangely when they see phantom and don't sound correct
Great video Dave ...often contemplated these things. Do you subscribe to having phantom both ends of the snake then for voltage stabilities sake and have you ever found a change in practical sound from any condenser that has a phantom fluctuate from 48v to as low as you’ve measured.
The one thing I’ve missed is your opinion on what some of these experiments show you about the quality of the sound the different environments make. Was especially interested in your cascading channel analogue vs digital mixer experiments ...there were some raised eyebrows but nothing on the audio aesthetics. Nice one for the videos mate ...what else does one do when there’s nothing to mix
Cool cool. Having the added phantom voltage should at best, just offer slightly more headroom as well as redundancy. The main point is that it does not hurt anything. And ever so slightly could help.
Fantastic video.
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Thank you so much for sharing your talents and experience with all of us.
I have a question. I want to utilize 2 AT4033 large diaphragm condenser mics in my acoustic trio. I also love the sound of our Meinl slap top cajon with passive pickups connected directly. Im told by percussion dealers that phantom power will damage it and our small Bose digital mixer doesnt have individual channel control of phantom power. How can I protect the cajon? Will the low Z output of any passive direct box isolate and serve the purpose? Do I need a specific device?
Thanks again!
Yes, the output of a direct box will block phantom. Or use and isolation transformer. Or make a special xlr cable that has 100uf capacitors on pin 2 and pin 3. Phantom won't go through a capacitor.
@@DaveRat Thank you so much! Your approach and egoless attitude are rare and so refreshing in this business. You should write a book or a series. I'm sure they'd be VALUABLE go to resources for all of us. Your knowledge and experience needs to be preserved.
Thank you!
@@tlb2732 thank you Tony and much appreciated!
Thanks for teaching me what a balanced cable is. A question... If the two different consoles are at slightly different voltages, theory tells me would that cause some current flow between the two units. Have you any idea how the two different power supplies cope with that? Obviously, no magic smoke is released! Thanks!
All input and output voltages are either floating or references to ground. Inputs look at the differential between the two hots on balanced lines and the diff between hot and ground on unbalanced.
Outputs create the same things.
As long at the gear is either isolated through a transformer or other method like being battery powered or references to the same ground as the other gear, all good.
Differing ground potentials on non isolated gear causes issues
The one with the higher voltage will be providing most of the current. The internal 6.8K resistors help out with current sharing, so the difference will be small.
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Question please. I have a splitter that itself provides phantom for each channel if needed. In your scenario above, I am assuming that a voltage drop occurs because I have two consoles FOH and monitor not turned on for phantom as I have been relying solely on the splitter source for the power. I don't use enough condensers that I think it would cause too far a drop, but with that scenario, should I be keeping it as I have it or should I have phantom on both channels from both boards as well as the phantom on the splitter. My boards allow phantom to be selected for each channel needed vs powering the entire board. Thanks for the explanation, it makes sense, I just never gave it a thought before 🙂
If your splitter supplies phantom, just use that. The sitter will most surely block the phantom from the consoles so console phantom is not needed
I can see that the cats stagebox seems to pass Phantom power. I wanted to know if that same stagebox would be able to pass phantom power across a cat6 cable going into the snake?
Yes, it will pass phantom and each channel can be individually phantom powered, works just like a 4 channel snake with disconnects.
Good timing on this one for me Dave. I have a Focusrite 18i20 interface, I run a pair of TRS to XLR cables from its outputs into a snake or inputs on a mixer. I’ve been worried about somebody sending me phantom power to the interface outputs. I doubt the interface outputs are transformer isolated, so because there’s no power on the tip or ring, I should be ok? I’d only have a problem if I was running 1/4” to XLR unbalanced cables, correct? I was thinking about buying or making a two channel transformer isolation box to safeguard against this, but if I run balanced cables I’m ok, unless there’s a problem with the snake?
Avoid running phantom to electronic inputs. Capacitor iso will solve but often electronic inputs don't like the 48 v DC offset that phantom sends and will act strangely
Dave Rat - yeah I would never intentionally run phantom power to them, I’m just concerned if it happens accidentally. Thanks Dave.
You can test for isolation by checking continuity of the grounds for both the input and the output --- if there is no continuity then they are isolated.
@@HazeAnderson 👍
Fantastic vid as usual Dave! Would love to hear your recommendations for study material regarding Power in the live environment. I know i'm not up to scratch on power, and with Universities putting out more engineers, I feel like power is the least understood part of this job. Hope you're in good health! ALSO WHO PUTS SUB ON THE OUTRO OF THE VIDEO?
I don't have good reference for live event power, definitely would be a good thing to find. Lots of stuff to know as well as conflicting regulations depending on country and portable versus fixed wiring.
Between monitor and foh, do separate mains power/phases create any audible issues?
They shouldn't as long as the grounds and feeds come from the same general source or as long as foh and mons are well isolated.
Hi Dave. Thanks for the video! I do not fully understand how everything (phantom)power works, so I have one question.
When connecting the two consoles, why doesn’t the phantom power of console 1 hurt the pre amps from console 2? If I am correct, the cables are directly attached to both consoles. Does the XLR split prevent that from happening, or is it completely fine for the pre amps to receive +48 from the other console?
Thanks in advance!
All consoles and most if not all mics are designed such that phantom power will not hurt them. Also, phantom power, is very very low power, typically way less than .5 watts per leg. For comparison, a USB -C cable can deliver up to 100W. So USB-C can be 200 x as powerful and damaging as phantom power. Even though phantom is 48v, it is severely current limited so as soon as it sees even the slightest load, it drops in voltage very quickly.
It would take a few weeks to charge you phone with phantom power
Dave, Is there ever any chance of having too many consoles running phantom power in parallel that could possibly cause injury from too much accumulated current due to a faulty snake system?
Two seperate issues. Faulty snake can give annoying shocks to the lips and hurt some mics with phantom. Paralleling 3, 4 or 5 consoles w phantom still has way way less power than a USB
@@DaveRat Thank you!
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Not an issue. Current is limited to about 7mA per device.
Agreed, power is so low that it is not possible to injure someone.
But I have been called out to fix a a system where a gal was getting shocked and fount phantom power and a faulty snake ground was putting 48v on her lips when she sang and held her guitar.
Enjoyed the explanation, another question popped up - what would happen if the phantom power was on from both consoles and an unbalanced/shorted (pin1 to pin2) cable was used? Thanks again.
The unbalanced cable would short out the phantom on pin 2 supplying 1/2 the current to a condenser mic but the second console would replace the missing current, dynamic mics would see double the current across the voice coil or internal transformer. The console would be fine as phantom is designed to be ok with being shorted
Dave Rat ah I see, thanks.
I’m wondering what happens when you split the mic cables and have two desks both supplying phantom power ? Ps not finished video yet :-)
Haha just watched the rest 👍🏻
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I wonder if there is any microphone response difference if 3 or more consoles drag down the voltage enough?
Any pro OB set up I've seen always used an active 3rd split anyway.
Would having 3 phantom switches on 1channel triple the current then?
3 should triple the current assuming you have a splitter that passes phantom
great video...
what about mics with batteries. good or bad?
The best mics don't have batteries but having an onboard power source does not make a mic bad
I've had a few cool mics over the years with batteries.
Excellent vid! Does splitting a microphone signal with one of those Y-cables, if connected to both mixers, cause any degradation of sound quality?
It should not and is easy to test, just listen or measure the output of one console while plugging and unplugging the other console. Typically a console input will be like 10,000 ohms or so and a mic output will be 200 ohms or so. So, you can drive several consoles with very minimal impact on the mic output level and loading of the mic.
Thank you Dave , I wonted to connect a 15 too 48 source I'm afraid I hope this is what your covering.
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Thanks for the video, what happens if you supply phantom to a DI box with the ground lift switch engaged, how does the direct box get voltage?
Great question. Phantom is supplied from the console to the output XLR of the DI. Where a phantom DI will grab the phantom to power it's internal circuits.
The ground lift on a DI is breaking the ground connection from the input ground to the output pin 1. So the input signal is grabbed by the di and outputted on pins 2 and 3 of the XLR and the input is not connected to the output ground.
The isolation of the input to the output can be done with electronics or with a transformer then boosted by electronics.
Thanks!
Cool cool
A lot of DIs don't fully disconnect when the ground lift is engaged. Pin one is still connected via a parallel 100 ohm resistor and 0.1uF capacitor. This allows enough current to pass to power an active DI but is enough resistance to reduce earth loops.
In a large venue where FOH and Monitor World might be on a different Phase/Leg as far as their power source will this cause an issue?
Typically a differing phase is not an issue. Its when the ground for mons and FOH are different and not tied back to the same place that issues arise. Since neutral is tied to ground somewhere in most, if not all, power systems, loads on the neutral can drag it off of zero volts and possibly drag the ground off of zero volts. Or if there is gear that somehow causes the ground to not be zero volts, that can cause issues if the ground at FOH is differing in voltage to the ground at mons. With digital snakes, this is less of an issue and usually a non issue as long as the ground offset voltages are small. With analog snakes and interconnects, even very small offsets in voltage between the ground at FOH and mons can cause hum and buzz issues. Large ground voltage offsets can be dangerous or deadly.
Hi Dave. I remember years back when using analog consoles and hardwire split snakes, if you had phantom coming from both FOH & Monitor consoles, you would almost always get a buzz. Was this another issue? You mentioned using multiple phantom sources as a practice.
Interesting, for years I toured with hardwired splits, avoiding the sound differentials cause by transformers. And used dual phantom as a norm without issues.
Phantom power cannot cause a buzz as it's DC. You probably had a grounding problem.
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Great video Dave!
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nice topic....i have been wonding about it quite a while ago and i didnt found answer, thanks for that
another question would be, what will happen if you feed line output signal from one cosole to the phantom powered input of another console?
Sending phantom to electronic outputs can give varied and often undesirable results. Due to the wide diversity of output circuit designs, there is no rule to whether it will have a negative impact, other than avoid it.
Phantom can be blocked with a pair of capacitors inline on pins 2 and 3 of an XLR or using an iso transformer
@@DaveRat thanks, that what I was thinking about it. I didn't try it though I always used active DI box because I was not sure what is gonna happen.
Can the phantom power ever damage either of the consoles providing it if the split is passive/not transformer isolated? I would assume the power would travel back up the split into each other. i.e. monitor and FoH console both going into a passive split - I'm just wondering how people get away with passive splits in this case
Consoles that can create 0hatomenpower are immune to damage from phantom power.
Most mic preamps are immune to phantom power impacting them.
Transformers are immune
Most input circuits are immune
Some or many output circuits are not immune and will either act strangely or possible be damaged.
Except:
Mic output circuits are almost always ummune
As a rule of thumb, phantom on input circuits, all good, phantom to out put circuits, not good.
Passive splits is connecting multiple input circuits to a mic output
Thanks for the vid, could you help me a bit?
I have an effect pedal with constant 24V phantom power, will it make any harm if i use it in a chain like this:
Condenser mic --> external power supply with phantom power 48V --> effect pedal with constant 24V --> audio interface with turned off phantom power --> pc
Phantom power into balanced outputs should not hurt anything. I have seen some outputs don't like it and either distort or offer reduced output levels when phantom is went to them.
Just try it. If it works and sounds ok, roll with it
It looked like plugging a mic into both mixers supplying power dropped the voltage less than with one supplying power. Seems like it can only be helpful having every console supplying it, especially if there's a lot of condenser mics being used. Which brings me to my main question, how many mics can one mixer supply power to? At what point do you need to add another supply?
Each mic channel is independently current limited by the console Thule console can supply power to as many Mike's is there are channels.
Dave, I know this is wrong..... but, in case I need to use a XLR to mini jack (1/8"), should I use pin 2 and pin 3 only on XLR like hot and gnd, not using the pin 1? Thanks for all you do here, your videos are amazing!
Typically you would run pin 2 to the mini tip, and short pin 3 to ground and run the shorted pair to mini ground
And turn off phantom power on that channel, if possible. Using a direct box or transformer is much better.
Great explanation (as always on this channel)! I have one question though: If we have phantom power switched on at house and monitor consoles and the two consoles do not share the exact same ground (on the AC side, i.e. 120V or 230V depending on where you are); are maybe plugged into power outlets from different distribution boxes. In that case, we'd have some steady current on the (XLR) cables connecting the two consoles, specifically the ground wires, i.e., pin 1? To level out the difference in ground potential. Isn't this dangerous to the very thin mic cables?
Whether you supply phantom power or not the grounds of both consoles are connected together via the XLR lines unless specifically lifted. So any ground differential potentials that exist will exist regardless of whether phantom power is applied from one console both consoles or neither console
Great content as always Dave! Also suggest hiding some people in the comments
Hmmm, not sure who to hide but a good. We can absorb all perspectives with a smile
Is the ethercon breakout boxes wired T568A or T568B? Would this have something to do with why my ethercon system is not lining up 1 for 1? I wired my whole system T568B.
Shoot me an email at daveratsound@gmail.com and will help ya sort.
If you wanted to go from one mic into Y split cable and then onto 2 inputs of the same same mixer ( double patch type thing)
Would it be the same as the 2 mixer set up?
As I have often thought if doing this one apply 48V to one of the inputs.
Yes, I would supply phantom from both and or all console inputs
Hi Dave, I have seen a lot of debate about allowing phantom power to feedback from a mixer into a Line6 Helix pedalboard's XLR line-outs. It sounds to me like the voltage on pins 2 & 3 shouldn't cause any problems if all of the equipment is working properly and the ground doesn't get involved and there are no shorts. Have you ever been a part of that conversation with any guitar players at a gig? I suppose there could be circuitry at the Helix end that would affect how the voltage is "seen" by the Helix? One of the suggestions was to use a voltage blocker in the XLR lines. Would it be a diode that would work like a check valve?
Hmmm, some electronic outs don't like phantom, I will look into doing a test and fix vid for you
I've seen this in person while mixing. It will seriously degrade the audio quality, very obvious distortion.
You can also just float pin 1 at the pedal if you're concerned. Many pieces of gear actually do that depending on their output circuit dont need the ground and the shield is still effective single ended (like most dynamic mics)
Finally I have support when I’m arguing with other engineers claiming phantom power is bad for mics that don’t need it
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Great Stuff,
Is there any Microphone designed for both propose....? out of curiosity..
Dynamic mics don't need phantom, condenser mics usually do need it. Some ribbon mics need phantom and some do not.
It's like a battery, some things like a radio, needs a battery, and something's like a hammer do not and and something's like an ice box can be powered to cool things and others just keep things cool and don't need power
So if I inject phantom power to a mic and use the one side of the xlr output of the mic to the unbalance mic input of a DSLR, ill kill it with 18v in the audio path?
Oh my, yeah, it gets complex but yes, phantom power is not typically compatible with unbalanced.
Using a small transformer to convert to unbalanced while phantom and the mic are on the balanced side of the traslnsformer is good.
Thanks Dave.
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Great Video. 😃👍♥️
Thank you Kevin!
very helpful video👍
Thank you Mika!