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Old September 1st, 2006, 12:51 AM   #1
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Hi-Md mic plug?

Picked up a Sony H-MD MZ NH700 mini disc for back up sound.I just noticed that on the microphone input plug it reads Mic(plug in power).I intend using the recorder with an Electro Voice RE50/B omni derectional dynamic,non powered mic.Question for all you guys who use the mini disc recorders.
Is there any kind of issue if I plug the above type of mic in the Mic(plug in power)socket?
The last thing I want is to electricaly fry my RE50 or my AT897 shotgun.
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Old September 1st, 2006, 01:33 AM   #2
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MD's are just like camcorders in how much power they supply to a mic. Both supply what is referred to as plug in power. It is a very low voltage power designed to power mics just like yours.

There shouldn't be any problem using either of your mics with a MD. HIMD is the same also BTW. The plug in power from the MD runs at max 2.5 v which isn't much. It's made to work with mics like that AT897 and your Electrovoice.

I know people are using AT897 mics with their MD's. Plug in power isn't likely to ever hurt anything really. It just isn't strong enough to hurt anything. That's why mics like the AT897 have their own power supply. Plug in power isn't very strong.

Your Electrovoice mic is no doubt meant to be powered by plug in power. All mics need some power to operate. Some mics are designed to work with plug in power. Yours is no doubt one of them. In fact many people add battery boxes to increase the power to a mic like that because plug in power is so low.
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Old September 1st, 2006, 07:53 AM   #3
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Quote:
Originally Posted by Jeff Phelps
MD's are just like camcorders in how much power they supply to a mic. Both supply what is referred to as plug in power..
That part is correct.
Quote:
Originally Posted by Jeff Phelps
It is a very low voltage power designed to power mics just like yours..
That's not correct, it's designed to power small mics like those that Sony and others make for use with camcorders and MD's. It's not helpful for any balanced mic.

Quote:
Originally Posted by Jeff Phelps
There shouldn't be any problem using either of your mics with a MD. HIMD is the same also BTW. The plug in power from the MD runs at max 2.5 v which isn't much. It's made to work with mics like that AT897 and your Electrovoice.
Not correct. The plug-in power can produce extreme noises if your mini-plug connection isn't totally secure, which is almost always. To fully eliminate this problem you should use an adapter with a capacitor designed to stop this voltage.

Quote:
Originally Posted by Jeff Phelps
I know people are using AT897 mics with their MD's. Plug in power isn't likely to ever hurt anything really. It just isn't strong enough to hurt anything. That's why mics like the AT897 have their own power supply. Plug in power isn't very strong...
It's true it isn't likely to hurt anything, except your audio signal if your connection isn't secure.

Quote:
Originally Posted by Jeff Phelps
Your Electrovoice mic is no doubt meant to be powered by plug in power. All mics need some power to operate. Some mics are designed to work with plug in power. Yours is no doubt one of them. In fact many people add battery boxes to increase the power to a mic like that because plug in power is so low.
The RE50 and any other dynamic mic requires no power to operate. In fact, I have several operating right now... inside their cases stored in the closet with no cables attached.
There are mics designed to work with plug-in power. And it is true that people add battery boxes to increase their power for better results.
But the RE50 and AT897 aren't in that category of mics.
I would suggest getting an adapter that allows you to maintain a balanced connection to your mics, with minimal unbalanced cable length into the recorder. As well as having a capacitor to eliminate any noise that can come from the plug-in power.
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Old September 1st, 2006, 08:51 AM   #4
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Quote:
Originally Posted by Jay Massengill
...
Not correct. The plug-in power can produce extreme noises if your mini-plug connection isn't totally secure, which is almost always. To fully eliminate this problem you should use an adapter with a capacitor designed to stop this voltage.
...
It's true it isn't likely to hurt anything, except your audio signal if your connection isn't secure.
...
After giving almost exactly the same answer as yours here to a comment by Andreas in the Digital Recorder thread also running right now, I got to wondering just what effects plugin power voltage might have on a dynamic in addition to the connection noise you mentioned. A little research turned up the fact that soundcards, camcorder, etc apply their voltage in a couple of different ways - between the ring and sleeve of a mini-TRS connector and between the tip and sleeve of a mini-TS connector, or sometimes even both tip and ring of a stereo mic input. Now couple that with the facts that a balanced XLR to unbalanced adapter shorts pin 3 to sleeve and the coil in a balanced dynamic mic is connected across pins 2 & 3 in the XLR. Some mics like the EV RE20 have a transformer and that would isolate the coil from DC except during the moment of connection but in others, like the EV RE50, the coil is connected directly to the output. With one of those, if you used an adapter without a DC blocking capacitor and plugged the mic into an input that has plug-in on the ring and sleeve no problem, but if it's plugged into one the devices that puts the power on the tip, you now have 5 or so volts directly across the mic's coil. That constant current flowing in the coil would cause the diaphram to move in or out and hold that position under tension, something I'd expect would have very pronounced negative effects on the audio it delivers. I can't help thinking that would not be good for the mic and certainly not good for the sound,.
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Old September 1st, 2006, 10:50 AM   #5
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Originally Posted by Steve House
After giving almost exactly the same answer as yours here to a comment by Andreas in the Digital Recorder thread also running right now, I got to wondering just what effects plugin power voltage might have on a dynamic in addition to the connection noise you mentioned. A little research turned up the fact that soundcards, camcorder, etc apply their voltage in a couple of different ways - between the ring and sleeve of a mini-TRS connector and between the tip and sleeve of a mini-TS connector, or sometimes even both tip and ring of a stereo mic input. Now couple that with the facts that a balanced XLR to unbalanced adapter shorts pin 3 to sleeve and the coil in a balanced dynamic mic is connected across pins 2 & 3 in the XLR. Some mics like the EV RE20 have a transformer and that would isolate the coil from DC except during the moment of connection but in others, like the EV RE50, the coil is connected directly to the output. With one of those, if you used an adapter without a DC blocking capacitor and plugged the mic into an input that has plug-in on the ring and sleeve no problem, but if it's plugged into one the devices that puts the power on the tip, you now have 5 or so volts directly across the mic's coil. That constant current flowing in the coil would cause the diaphram to move in or out and hold that position under tension, something I'd expect would have very pronounced negative effects on the audio it delivers. I can't help thinking that would not be good for the mic and certainly not good for the sound,.
For us laymen, if I use the following set up, will I be okay. I sometimes use this set up when I am not recording directly to camera:

ME66 powered by K6, to XLR adapter, XLR adapter to HiMD.

Seems to work for me, but if I can improve, what would I need to do ?
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Old September 1st, 2006, 12:14 PM   #6
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Originally Posted by Chris Barcellos
For us laymen, if I use the following set up, will I be okay. I sometimes use this set up when I am not recording directly to camera:

ME66 powered by K6, to XLR adapter, XLR adapter to HiMD.

Seems to work for me, but if I can improve, what would I need to do ?
What kind of XLR adapter are you using? I'd expect everything is fine with your setup if it's working okay but if you want to check ...

Take the following with a grain of salt. The problem is there are three possibilities for how the manufacturer's external mic might be connected to your HiMD and I havern't used one so I don't know which applies to yours ...

Mono mic, TRS plug, signal on tip, power on the ring, ground on sleeve
Mono mic, TS plug, signal plus power on the tip, ground on sleeve
Stereo mic, TRS plug, left on tip, right on ring, power on both, ground on sleeve.

Assuming the external mic is mono and it's split to both stereo channels inside the recorder. If your adapter is just a cable with an XLR on one end and a miniplug on the other, it would only take a second to check to see if it's wired correctly and has the blocking capactor in it. Get a multimeter (if you don't have one you can get one at Radio Shack for about $20) and see if it shows connected or open between pin 2 on the XLR connector and the tip of the miniplug. If it reads open, then there's a capacitor in there to block DC. If it shows a short, then there isn't. If the miniplug is a TRS, the ring and sleeve should be shorted together and whether its TRS or TS, pin 1 of the XLR should connect to the sleeve. XLR pin 3 is unconnected.

If the HiMD is designed for a stereo external mic and you're using a simple XLR to miniplug cable, it changes a little. A consumer stereo mic's wiring has the left channel on the tip, the right channel on the ring, and a common ground in the sleeve with the plug-in power voltage applied on both the tip and the ring. In that case, the XLR pin 1 should be connected to the sleeve of the miniplug. XLR pin 2 should connect to the tip of the miniplug through the blocking capacitor and the miniplug's tip and ring jumpered together inside the connector. Again, XLR pin 3 is unconnected.

In some cases you might need to jumper XLR pins 1 & 3 together, especially with dynamic mics, but I doubt you'll need to - try without them connected first and if you don't get any signal or it seems noisy, try with them connected and see which way works better.
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Old September 1st, 2006, 01:19 PM   #7
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Steve's right. Plug-in power will cause catastrophic problems with audio recorded with a balanced signal. Many (most?) XLR adapters have voltage blocking capacitors though, so it's not that big of a deal for most people. I've used an ME66 with minidisc many times using XLR adapters made by Shure and Studio 1 though.
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Old September 1st, 2006, 02:15 PM   #8
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Yeah, Steve, I didn't make that clear. I was actually talking about the Beachtek DXA-4 I normally would mount on my camera..
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Old September 1st, 2006, 02:20 PM   #9
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Yeah, Steve, I didn't make that clear. I was actually talking about the Beachtek DXA-4 I normally would mount on my camera..
Yep, AFAIK that will block the DC and should work just fine.
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Old September 1st, 2006, 11:59 PM   #10
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Originally Posted by Jay Massengill
That part is correct.

That's not correct, it's designed to power small mics like those that Sony and others make for use with camcorders and MD's. It's not helpful for any balanced mic.
Many mics are certainly powered by plug in power. I can cite many examples if you like. Sorry but that's really not an error on my part. The question didn't mention that the mic was a balanced mic with XLR connecters.

Quote:
Not correct. The plug-in power can produce extreme noises if your mini-plug connection isn't totally secure, which is almost always. To fully eliminate this problem you should use an adapter with a capacitor designed to stop this voltage.
Sheesh talk about nit picking. Any setup can be screwed by plugs that aren't connected properly. You failed to mention that plug in power doesn't work if you fail to plug it in at all. Since we're covering all the incredibly obvious bases don't forget this one.

Quote:
And it is true that people add battery boxes to increase their power for better results.
But the RE50 and AT897 aren't in that category of mics.
Didn't I say that the AT had it's own power supply? Self powered mics don't need battery boxes. Yep I'm sure I said that.

Excuse me for not thinking someone would be asking about plugging a balanced mic into a minidisk. They don't have balanced connecters last time I checked. I would have expected some mention to be made of that fact since he did speak of connecting it to the MD he bought. Sure you can get an adapter. I have one so I know they make them. But it's "incredibly obvious day" so I thought I should mention it.

Pretty much any mic made to plug into a MD player should operate with that player with no problems. Only mics that require an adapter might have problems. Excuse me that I didn't know he was going to be using an adapter.
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Old September 2nd, 2006, 07:08 AM   #11
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Originally Posted by Jeff Phelps
MD's are just like camcorders in how much power they supply to a mic. Both supply what is referred to as plug in power. It is a very low voltage power designed to power mics just like yours.

...The plug in power from the MD ...[Is] made to work with mics like that AT897 and your Electrovoice...

Your Electrovoice mic is no doubt meant to be powered by plug in power. All mics need some power to operate. Some mics are designed to work with plug in power. Yours is no doubt one of them. In fact many people add battery boxes to increase the power to a mic like that because plug in power is so low.
You said all mics need power but that's just not true. You also said plug-in power was intended to supply the needs of mics like the AT897 and the EV RE50 and that's not true either.

The EV mic he was referring to is a dynamic mic. Dynamic mics do not requre ANY power source to function, be it plug-in, phantom, internal battery, or external battery box. Why? Because they are a micro-generator in their own right, converting sound vibration into electrical energy by moving a coil in a magnetic field.

The AT897 is a condensor mic and it does require power, but it is NOT made to work with plug-in power or an external battery box. The 897 works either on its internal battery or on phantom power, but phantom and plug-in power are two entirely different things in terms of both voltage levels and connection method, and one cannot be substituted for the other. The 897 WILL NOT work with plug-in nor with an external battery box (unless the box happens to be an external, battery-driven, phantom power supply), the best you can say is it might not be affected by plug-in when used with a pience of equipment that provides it. Nor will it's signal be "boosted" by such an external battery box unless the box happens to be a mic preamp such as a Beach DXA-8 or -10 or a SD MM-1.
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Old September 2nd, 2006, 08:54 PM   #12
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Originally Posted by Marco Leavitt
Steve's right. Plug-in power will cause catastrophic problems with audio recorded with a balanced signal. Many (most?) XLR adapters have voltage blocking capacitors though, so it's not that big of a deal for most people. I've used an ME66 with minidisc many times using XLR adapters made by Shure and Studio 1 though.
My Nady CM-2S came with an XLR to mini plug adapter. It is common to use balanced line mics with plug in power devices. Many balanced line mics have built in capacitors that block plug in power voltage. I'm sure the AT897 has such a capacitor or at least I know people say it does.

I'm guessing there are mics that don't have these capacitors but like you say many devices that adapt XLR to unbalanced have the capacitors built in. I believe the Beachtec models have them.
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Old September 3rd, 2006, 12:44 AM   #13
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You said all mics need power but that's just not true. You also said plug-in power was intended to supply the needs of mics like the AT897 and the EV RE50 and that's not true either.
I really should stop posting late at night. I was thinking of the AT822 actually when I said this because it comes with an unbalanced line adapter. I also said the AT is self powered. I should have said that condenser mics all require power or at least I believe they do.

Quote:
The EV mic he was referring to is a dynamic mic. Dynamic mics do not requre ANY power source to function, be it plug-in, phantom, internal battery, or external battery box. Why? Because they are a micro-generator in their own right, converting sound vibration into electrical energy by moving a coil in a magnetic field.
That's not true. Some dynamic mics certainly do require power. Most dynamic mics essentially create their own power the same way a generator does. They move parts near a magnet which creates a very slight voltage.

Quote:
The AT897 is a condensor mic and it does require power, but it is NOT made to work with plug-in power or an external battery box.
I was thinking of the AT892 which works with unbalanced lines with the supplied adapter but I specifically said it had it's own power supply anyway. Both the 897 and 892 have their own power supply. Because he mentioned plugging it into a MD unit I assumed he was talking about the 892 for some reason. I really need to stop posting so late at night I guess.

I guess where I got off track was thinking someone who said they were plugging a mic into a MD must be using mics with unbalanced cables. No mention was made of needing an adapter of any kind so I got it in my head that he was talking about the 892 which has it's own adapter so that essentially it works on either a balanced or an unbalanced line. At any rate no mention of the fact that his mics were both XLR made me think he was using mics that were unbalanced. Obviously I was wrong but the rush to point it out with such declaratory zeal seems out of place and unneccessary.

I found no such delight in pointing out your error even though my mistake was more understandable IMO. You were uninformed in the matter of powered dynamics while I just made a mistake of assuming a person speaking of plugging a mic into a MD could actually do that without using an adapter which wasn't mentioned.
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Old September 3rd, 2006, 07:27 AM   #14
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Originally Posted by Jeff Phelps
....

That's not true. Some dynamic mics certainly do require power. Most dynamic mics essentially create their own power the same way a generator does. They move parts near a magnet which creates a very slight voltage.

...
Interesting - I wasn't aware of the Blue. But you must admit, even the writeup in the URL you posted recognizes that this mic is a real odd-ball in that regard and the phantom power is being used for what sounds like essentially an internal active preamp & equalizing circuit and is not for the mic element per se as it is in a true condensor.

Only corrected you because I didn't want anyone reading this thread to get the idea that the mic plug-in power supplied by consumer gear such as computer soundcards, HiMD and iRiver/iPod type recorders, consumer camcorders, etc was at all related to the phantom power or internal battery power required by virtually all "serious" condensor mics. It's not even close to being the same thing - instead it's intended to power the external accessory mics the recorder manufacturers sell or the sort of cheap "accessory" electret mics you find in the blister-paks next to the register in big-box computer stores, in computer "multimedia" headsets, or at Radio Snak. Before anyone objects to my characterization of plug-in being intended to power "cheap consumer electrets," I know the Giant Squid mics are built to use it and they give acceptable results in professional use by wedding videographers etc. but one has to admit that a $30 Squid mic isn't really in the same class as a $300 Tram or Countryman.

I should add too that it is not a matter of balanced or unbalanced connections that makes the difference. While most better mics these days are balanced, true enough, it's not writ in granite that they must be and there are plenty of unbalanced mics out there. Plugin power isn't meant for most of them either.
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Old September 4th, 2006, 01:51 AM   #15
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There are certainly many "serious" mics that are made to adapt to unbalanced use. The AT892, which I mistakenly thought of in this thread, is a good example. It's a very good mic that comes with it's own adapter to the unbalanced world. Then there's the Rode VideoMic and the Stereo VideoMic. Both are hardly anything less than excellent quality.

My own Nady CM-2S records excellent quality and it comes packed with 2 XLR to unblanced cables and no straight XLR cables at all. My GS doesn't come with any XLR cable or any connection of that type at all.

I'll admit that these mics are not the top of the line but to label them as not "serious" strikes me as condescending. The only thing that makes XLR any better is the shielding. To say that HIMD recorders are less than serious is to miss the boat if you ask me.

You sound like the producer of many Beatles albums, Geore Martin, who disapproves of excessively convenient recording technology (read cheap) because it takes the ability out of the hands of the few and gives it to the many. You might find the quality of lesser known equipment to be startling if you give it a try. There's a lot of snobbery in the world of audio it seems. I don't know you well enough to say whether you fall into that category but many do. Martin said we could all be producing albums in our bathtubs that equal the quality of those Beatles albums. I hate to tell George but we can exceed that limited early 1960's quality quite easily and do it in the bathtub (where no AC power is allowed of course). HIMD is very good quality and so are many of the unbalanced mics you lump together and deride. The few who can actually hear the difference between a HIMD recording using a GS compared to the best quality money can buy can spend their money on something better if they choose. The other 99% of the population will do just fine without the extra cost thank you.

Maybe the mic preamps aren't the best in the world. And maybe the unbalanced lines require extra short cable runs. But the noise level is actually very low compared to much of the stuff on the radio because of the fact that levels on those radio songs are pushed to the max and headroom is nil (and maxed out levels mean more noise of course). HIMD is a music format for the most part and it compares favorably to much of the trash being sold by the truckload at Wally World. Have you heard the stuff they sell there? Don't tell me you can't produce that level of quality on HIMD. Low cost, high quality pre-amps are also commonly sold for these devices so you can get around the one true limitation they have. XLR adapters are certainly not uncommon either. Our friend here must be using them.

The fact is (IMO of course) that cheap equipment can produce very high quality these days. It may not be on the level of the high priced stuff but it's on the level of the high priced stuff of just a few years ago. Quality is relative and the progression of increased quality has a much more shallow angle on a flow chart than the price progression to obtain that quality. How good is good enough? You might find that many here are gear heads and as such they are not at all concerned with the bottom line and the question of how good does it need to be to be acceptable. Some of us make money with equipment on the low end of the scale and get surprising results in the process.
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