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#41
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Ribbon Mic picking up Radio Frequency Interference
"Truth" wrote ...
Eeyore wrote: Truth wrote: I even got some special power cords for the mic power supplies. Why ? What did you expect it to do ? AC power doesn't need 'special cords'. They're only for gullible 'audiophools'. Graham Here are the cables I mentioned for the power supplies. http://www.silversonic.com/docs/products/PowerPlus.html Yes, that is exactly what we mean by "snake-oil" products designed especially for "audiophools" who have more dollars than sense. Their only remarkable feature is their high price. Technically, they do absolutely nothing. And if you *did* have a power-mains-borne noise problem, that magic cable wouldn't fix it anyway. Those things are much worse than nothing because they promise what they cannot deliver and they just take ridiculous amounts of money by trying to cheat you. But it seems highly unlikely that your problem has anything to do with power of any kind. That includes AC power from the wall plug all the way through the power supply for your mics. |
#42
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Ribbon Mic picking up Radio Frequency Interference
I'm coming in late, so sorry if I repeat something some else already said.
If the mic is on a stand, try coiling the cable around the stand. I learned this about 25 years ago, when experiencing RFI at a concert. Coiling the cable can introduce enough inductance to "choke" the RF. |
#43
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Ribbon Mic picking up Radio Frequency Interference
Truth wrote:
House Power Ribbon Mic's Power Box Ribbon Mic's non standard cable, very long about 20 feet( I can't swap it out to test it with something else) 2 Royer 122V Ribbon Mics OKAY! So you don't have normal ribbon microphones at all. You have the 122V. So, the first question: Do you hear the problem with the 122V turned off? If turning off the mike stops the noise, the rectification is taking place inside the mike. The second question: If you connect up only a single microphone, do you hear it? --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#44
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Ribbon Mic picking up Radio Frequency Interference
Eeyore wrote:
Scott Dorsey wrote: Eeyore wrote: Scott Dorsey wrote: AndyP wrote: Does a preamp with a transformer balanced input do a better job rejecting RF? Almost always. There are some poorly-designed transformer inputs out there too, though. What kind of preamp, microphone, and cable are we dealing with here? And what makes you think it's AM? He said it was an AM station. Right, but he said he was hearing a whistle. AM is also readily demodulated by any diode-like behaviour. Yes, but then you hear voices. You got me there. Joke ? No, when AM radio is demodulated in an audio chain, you can hear the modulation of the AM signal, which is usually music or an announcer. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#45
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
Truth wrote:
The cable connecting the ribbon mic to it's dedicated power supply is a 7 pin cable provided by Royer Labs. Could the problem originate in the power and get intensified by the Mic's Power Supply and cables, or the mic itself? If it's an RF problem, it has nothing to do with the power system. I'm not so sure it _is_ an RF problem, though. When you heard this squealing sound on an AM radio tuned to 790, was your audio gear operating at the time? --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#46
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Ribbon Mic picking up Radio Frequency Interference
On Sep 13, 1:27 pm, "William Sommerwerck"
wrote: I'm coming in late, so sorry if I repeat something some else already said. If the mic is on a stand, try coiling the cable around the stand. I learned this about 25 years ago, when experiencing RFI at a concert. Coiling the cable can introduce enough inductance to "choke" the RF. Thanks very much for that tip, I will give that a try if the problem comes back. Right now, I'm not hearing it. |
#47
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Ribbon Mic picking up Radio Frequency Interference
On Sep 13, 12:44 pm, (Don Pearce) wrote:
On Thu, 13 Sep 2007 09:36:00 -0700, Truth wrote: On Sep 13, 12:31 pm, Mike Rivers wrote: On Sep 13, 12:06 pm, Truth wrote: These are two brand new Royer 122V Tube Ribbon Microphones. I sent the first two I received back to Royer and they sent me two brand new replacements. They told me to keep them away from dimmers, motors, fluorescent lights, etc. They also mentioned that the mics can act like antennas. If that is the case, then what can be done about it? Move. Could the problem originate in the power source and made worse by long cable runs? That's the easiest part to RF-proof, and I suspect that they've done a reasonable job of it, but I don't know for sure. The RF could be being picked up by the microphone element itself (there's only so much shielding they can do and still let sound in), but it's not likely that the cable is the problem. The output of the microphone is a cathode follower, which I suspect does not go through a transformer, at least not until it gets into the power supply box. That means an unbalanced cable run which, even though it's a low impedance source (the tube in the microphone) can still act as an antenna. The output of the system is balanced, but it's not clear from the data I have available where the balancing occurs. So you may very well have a 20 foot antenna ahead of your mic preamp. Or, if the RF field strength is great enough, the tube in the mic could be acting like a diode and detecting the radio signal. You should try taking the mics and a preamp somewhere else. You don't need the whole computer rig, just a set of headphones. I'm able to monitor direct from the Pendulum preamp and I hear the squeal there before it gets to the computer. I'm thinking a shorter run mic cable between the power box and mic might help. Before you are forced to anything drastic, try some clamp-on RF stoppers - the kind you find on the end of your VGA monitor cable. You can get these in most electronics parts houses. Go for the lowest frequency spec they have. Put them on all the cables (starting with the mic cable) close to the preamp, and see which stops, or at least reduces, the effect. d -- Pearce Consultinghttp://www.pearce.uk.com Ok, I will look into that, thanks. |
#48
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
"Truth" wrote in message
oups.com... 790 AM I get lots of squeal/whistle when I tune into that station on a radio. I'm recording at 96K, 32bits. In reply to Paul Stamler I listed my recording chain. Mostly digital. The Pendulum is a tube preamp. When used with the ribbons I sometimes get a squeal. The Weiss ADC2 can send out analog and digital. I'm sending out a DO to the Lynx Two's DI. The Pendulum is an odd duck; it includes a tube in its signal chain, but as far as I can tell from reading the online stuff its input is transformerless. That means that the first thing the signal sees is probably a pair of bipolar transistors, which can demodulate AM if the circumstances are wrong. Likewise, the Weiss seems to be a transformerless solid-state preamp. So if the demodulation is happening in the preamp stage, that wouldn't surprise me in either case. Transformer inputs do help with situations like this. But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. If the tube in the microphone is accessible, take it out, coat the pins with a thin layer of DeoxIt, put the tube into the socket again, remove and wait a couple of minutes. Clean the pins with a Q-tip, reinsert, remove, clean them again, then coat them with a thin layer of PreservIt. I've gotten rid of annoying AM radio signals that way, by removing the metal oxide on the tube pins which makes a dandy demodulating diode. If the problem is still intractable, consider exchanging the mics for Royer's similar active ribbon mics incorporating a FET. Peace, Paul |
#49
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
"Truth" wrote in message
oups.com... The cable connecting the ribbon mic to it's dedicated power supply is a 7 pin cable provided by Royer Labs. Could the problem originate in the power and get intensified by the Mic's Power Supply and cables, or the mic itself? Much more likely in the mic itself. The transformer in the power supply is usually pretty good at filtering out RF on the line. Peace, Paul |
#50
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
On Sep 13, 1:14 pm, "Paul Stamler" wrote:
"Truth" wrote in message oups.com... The cable connecting the ribbon mic to it's dedicated power supply is a 7 pin cable provided by Royer Labs. Could the problem originate in the power and get intensified by the Mic's Power Supply and cables, or the mic itself? Much more likely in the mic itself. The transformer in the power supply is usually pretty good at filtering out RF on the line. Peace, Paul I'm gonna guess at this point that the mics power supply has a switching power supply in there and that the switching freq or harmonic thereof is beating with the 790 kHz AM station. If you turn off the mics and the power supplies do you still hear the squeal in the AM radio on 790? If you turn off all your audio equipment do you still hear the squeal in the AM radio? Does the squeal ever change pitch? If so what makes it change pitch? How far away from you is the 790 kHz AM radio stations antennas? Mark Mark |
#51
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
Paul Stamler wrote:
The Pendulum is an odd duck; it includes a tube in its signal chain, but as far as I can tell from reading the online stuff its input is transformerless. That means that the first thing the signal sees is probably a pair of bipolar transistors, which can demodulate AM if the circumstances are wrong. Likewise, the Weiss seems to be a transformerless solid-state preamp. So if the demodulation is happening in the preamp stage, that wouldn't surprise me in either case. Transformer inputs do help with situations like this. I bet a nickel that something is breaking out into oscillation and that the problem has nothing to do with RF interference. But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. If the tube in the microphone is accessible, take it out, coat the pins with a thin layer of DeoxIt, put the tube into the socket again, remove and wait a couple of minutes. Clean the pins with a Q-tip, reinsert, remove, clean them again, then coat them with a thin layer of PreservIt. I've gotten rid of annoying AM radio signals that way, by removing the metal oxide on the tube pins which makes a dandy demodulating diode. It is a known problem with all microphones, however I did not have any problem when I reviewed these mikes. I keyed a 1W handie-talkie on 146 MHz up within a few inches of the mike (which is my regular RF test). --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#52
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Ribbon Mic picking up Radio Frequency Interference
Truth wrote: Eeyore wrote: A DH Labs DI ? I can't find anything by googling. Is it active or passive ? Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the connection between the preamps and the sound card. What the heck is a "DH labs 12 feet 110 Ohm XLR". Are you using daft audiophool 'snake oil' cables ? I'd get rid of those straight away and use something sensible and reliable. Graham |
#53
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
Truth wrote: The cable connecting the ribbon mic to it's dedicated power supply is a 7 pin cable provided by Royer Labs. Could the problem originate in the power and get intensified by the Mic's Power Supply and cables, or the mic itself? Anyone's guess. For the life of me I don't understand why you'r fixating over the idea that the AC power is the problem. It's aboutt he leat likely thing ever ! Are you susceptible to the kind of audiophool nonsense that gave us the Tice Clock and the Shakti Stone and one way cables ? Hint, the guys selling that stuff are fraudsters and they talk nothing but garbage. You need to erase everything from your mind that you ever heard in the 'hi-fi' mags. So, is the 3 pin XLR mic output on the 'power supply' ? I've looked for the info but haven't found anything useful. Graham |
#54
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Ribbon Mic picking up Radio Frequency Interference
Truth wrote: I'm able to monitor direct from the Pendulum preamp and I hear the squeal there before it gets to the computer. Your idea that it's 'before' is flawed. Any interconnection can affect these things even if to you it appears not to be in the obvious signal path. Stuff can go 'backwards' (i.e from destination to source) down cables you see. Graham |
#55
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Ribbon Mic picking up Radio Frequency Interference
Truth wrote: Eeyore wrote: It sounds like they've been pumping you full of nonsense. No they are correct. When my LCD monitor is on I can hear a definite hum or buzz. When I turn it off it goes away, so I turn it off while recording. That proves the sum total of nothing other than poor product design. I know, I'm a pro-audio designer and pretty expert in RF interference matters actually. Because the microphones use magnetism to function they are prone to these problems. Rubbish. The fact the mics have a magnet inside is totally and completely irrelevant to RF pickup. Where the hell do you get this crap from ? What is especially relevant by the way is inductance and 'loop area'. They sound good when they work, As some badly designed equipment (especially esoteric hi-fi) often does. Graham |
#56
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
Truth wrote: Eeyore wrote: Truth wrote: I even got some special power cords for the mic power supplies. Why ? What did you expect it to do ? AC power doesn't need 'special cords'. They're only for gullible 'audiophools'. Here are the cables I mentioned for the power supplies. http://www.silversonic.com/docs/products/PowerPlus.html Oh Dear ! " The clarity of an audio signal is greatly affected by the components power supply " is fairly close to a straight LIE. It's certainly deceptive marketing. The power supply *can* affects the sound but that's down tot he internal *components* and circuit design. The power cable is NEVER responsible. Now you're talking to real professionals we'll put you on the right track. All that cable does btw is to transfer money out of your bank account and into someone else's. Graham |
#57
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Ribbon Mic picking up Radio Frequency Interference
Scott Dorsey wrote: Eeyore wrote: Scott Dorsey wrote: Eeyore wrote: Scott Dorsey wrote: AndyP wrote: Does a preamp with a transformer balanced input do a better job rejecting RF? Almost always. There are some poorly-designed transformer inputs out there too, though. What kind of preamp, microphone, and cable are we dealing with here? And what makes you think it's AM? He said it was an AM station. Right, but he said he was hearing a whistle. AM is also readily demodulated by any diode-like behaviour. Yes, but then you hear voices. You got me there. Joke ? No, when AM radio is demodulated in an audio chain, you can hear the modulation of the AM signal, which is usually music or an announcer. I thought he said he did hear that (and also the heterodynes or whatever) ? Graham |
#58
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Ribbon Mic picking up Radio Frequency Interference
Scott Dorsey wrote: Truth wrote: The cable connecting the ribbon mic to it's dedicated power supply is a 7 pin cable provided by Royer Labs. Could the problem originate in the power and get intensified by the Mic's Power Supply and cables, or the mic itself? If it's an RF problem, it has nothing to do with the power system. I'm not so sure it _is_ an RF problem, though. When you heard this squealing sound on an AM radio tuned to 790, was your audio gear operating at the time? LOL ! Good point. Graham |
#59
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Ribbon Mic picking up Radio Frequency Interference
Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? Graham |
#60
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Ribbon Mic picking up Radio Frequency Interference
Eeyore wrote:
Scott Dorsey wrote: Truth wrote: The cable connecting the ribbon mic to it's dedicated power supply is a 7 pin cable provided by Royer Labs. Could the problem originate in the power and get intensified by the Mic's Power Supply and cables, or the mic itself? If it's an RF problem, it has nothing to do with the power system. I'm not so sure it _is_ an RF problem, though. When you heard this squealing sound on an AM radio tuned to 790, was your audio gear operating at the time? LOL ! Good point. I bet a nickel it's an oscillation issue, yes. Not a quarter, but more than a penny. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#61
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Ribbon Mic picking up Radio Frequency Interference
"Truth" wrote... Here are the cables I mentioned for the power supplies. http://www.silversonic.com/docs/products/PowerPlus.html Is there some arrangement that we could make based on a percentage of savings relative to your current expenses, if I were to come and run your purchasing department? -- David Morgan (MAMS) http://www.m-a-m-s DOT com Morgan Audio Media Service Dallas, Texas (214) 662-9901 _______________________________________ http://www.januarysound.com |
#62
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Ribbon Mic picking up Radio Frequency Interference
Eeyore wrote:
Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? The head amp is really just a cathode follower. It has no gain, but it makes driving long cables easier and reduces perceived differences between preamps due to loading. Also it makes it possible to use a higher ratio transformer since the transformer has a fixed and known high-Z load. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#63
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
"Scott Dorsey" wrote in message
... But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. If the tube in the microphone is accessible, take it out, coat the pins with a thin layer of DeoxIt, put the tube into the socket again, remove and wait a couple of minutes. Clean the pins with a Q-tip, reinsert, remove, clean them again, then coat them with a thin layer of PreservIt. I've gotten rid of annoying AM radio signals that way, by removing the metal oxide on the tube pins which makes a dandy demodulating diode. It is a known problem with all microphones, however I did not have any problem when I reviewed these mikes. I keyed a 1W handie-talkie on 146 MHz up within a few inches of the mike (which is my regular RF test). Yes, but what happens (or doesn't happen) at 146MHz could be very different from what happens at 790kHz. Peace, Paul |
#64
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Ribbon Mic picking up Radio Frequency Interference
"Eeyore" wrote in message
... Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? It's not entirely daft. Many ribbon microphones have loading issues, and perform much better into a higher-impedance load. Into lower-impedance loads the response of the mic is overdamped, and high frequencies roll off extravagantly. That's why AEA's preamp, designed specifically for their ribbon microphones, has an input Z of 10k. Unfortunately, most modern preamps have an input Z between 1.2k and 2.5k, way lower than is ideal for these ribbons. So Royer (and other makers in imitation) chose to include head amplifiers which terminate the mics the way the want to be terminated, and send a signal to the preamp which is compatible with modern preamp designs. Peace, Paul |
#65
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
"Eeyore" wrote in message
... Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the connection between the preamps and the sound card. What the heck is a "DH labs 12 feet 110 Ohm XLR". Are you using daft audiophool 'snake oil' cables ? I'd get rid of those straight away and use something sensible and reliable. Eeyore, you're frothing again, and for no reason. 110 ohm XLR cables are designed to be compatible with AES/EBU digital signals. They also work fine for microphones, although they tend to be stiff and thus a bit unruly to handle. But using them means you can use the same batch of cables for analog audio or digital signals without worrying that you might grab the wrong cable by mistake. Peace, Paul |
#66
Posted to rec.audio.pro
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Ribbon Mic picking up Radio Frequency Interference
"Eeyore" wrote in message
... " The clarity of an audio signal is greatly affected by the components power supply " is fairly close to a straight LIE. It's certainly deceptive marketing. The power supply *can* affects the sound but that's down tot he internal *components* and circuit design. The power cable is NEVER responsible. Not entirely true, although nearly so. I once had to rebuild a piece of gear being used near a UHF-TV transmitter and, along with all the ferrite beads and ceramic discs needed to clean it up, I found it necessary to use a shielded power cord. It wasn't any SilverSonic thing, though, but one I bought from (I think) Mouser Electronics for $3.95. Peace, Paul |
#67
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Ribbon Mic picking up Radio Frequency Interference
"Paul Stamler" wrote ...
"Scott Dorsey" wrote ... It is a known problem with all microphones, however I did not have any problem when I reviewed these mikes. I keyed a 1W handie-talkie on 146 MHz up within a few inches of the mike (which is my regular RF test). Yes, but what happens (or doesn't happen) at 146MHz could be very different from what happens at 790kHz. But 1W a few inches away is a heckuvalot more RF to deal with than any AM, FM or TV broadcast transmitter. Regardless of wavelength. |
#68
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Ribbon Mic picking up Radio Frequency Interference
"Eeyore" wrote ...
Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? Same general reason every condensor microphone (conventional or electret) has a "head amp". i.e. impedance conversion (even if no signal gain). In the case of condenser the ultra-high impedance isn't practical to send down a conventional mic shielded pair. And in the case of the ribbon, the impedance is too low. Or to look at it another way, there's too much current and not enough voltage for conventional mic circuits. The traditional way to solve the problem was to use a step-up transformer. For example Lundahl LL2912, 2913, 2914 |
#69
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Ribbon Mic picking up Radio Frequency Interference
"Eeyore" wrote ...
Truth wrote: Eeyore wrote: It sounds like they've been pumping you full of nonsense. No they are correct. When my LCD monitor is on I can hear a definite hum or buzz. When I turn it off it goes away, so I turn it off while recording. That proves the sum total of nothing other than poor product design. I know, I'm a pro-audio designer and pretty expert in RF interference matters actually. Because the microphones use magnetism to function they are prone to these problems. Rubbish. The fact the mics have a magnet inside is totally and completely irrelevant to RF pickup. Where the hell do you get this crap from ? What is especially relevant by the way is inductance and 'loop area'. They sound good when they work, As some badly designed equipment (especially esoteric hi-fi) often does. Perhaps you are unaware that Royer has a rather good reputation on this side of the pond for making good products with what appears to be decent engineering and good customer relations, etc. There are more than enough vendors of shoddy or questionable equipment who are worthy of your rants, but I don't think Royer is among them. http://www.royerlabs.com/ |
#70
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Ribbon Mic picking up Radio Frequency Interference
Scott Dorsey wrote: Eeyore wrote: Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? The head amp is really just a cathode follower. It has no gain, but it makes driving long cables easier and reduces perceived differences between preamps due to loading. Also it makes it possible to use a higher ratio transformer since the transformer has a fixed and known high-Z load. I still don't understand what's wrong with having the ribbon drive the cable. Graham |
#71
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Ribbon Mic picking up Radio Frequency Interference
On Sep 13, 1:03 pm, Truth wrote:
That's the thing, I don't know what is the problem yet. It could be the house lines acting as antenna and not the equipment itself which is at fault. Well you have to stop guessing and start doing some troubleshooting. Start disconnecting things from the microphone back to the computer, one at a time, until the interference goes away. And start by turning off the radio. |
#72
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Ribbon Mic picking up Radio Frequency Interference
Paul Stamler wrote: "Scott Dorsey" wrote in message It is a known problem with all microphones, however I did not have any problem when I reviewed these mikes. I keyed a 1W handie-talkie on 146 MHz up within a few inches of the mike (which is my regular RF test). AM or FM ? Yes, but what happens (or doesn't happen) at 146MHz could be very different from what happens at 790kHz. Absolutely ! And that band is IME the one which typically causes all the trouble. Graham |
#73
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Ribbon Mic picking up Radio Frequency Interference
Paul Stamler wrote: "Eeyore" wrote Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? It's not entirely daft. Many ribbon microphones have loading issues, For any particular reason you know of ? and perform much better into a higher-impedance load. Into lower-impedance loads the response of the mic is overdamped, and high frequencies roll off extravagantly. That's why AEA's preamp, designed specifically for their ribbon microphones, has an input Z of 10k. Unfortunately, most modern preamps have an input Z between 1.2k and 2.5k, way lower than is ideal for these ribbons. So Royer (and other makers in imitation) chose to include head amplifiers which terminate the mics the way the want to be terminated, and send a signal to the preamp which is compatible with modern preamp designs. I saw it implied that as a result the cable has an unbalanced signal on it though which must introduce a whole new set of problems. Graham |
#74
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Ribbon Mic picking up Radio Frequency Interference
Paul Stamler wrote: "Eeyore" wrote Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the connection between the preamps and the sound card. What the heck is a "DH labs 12 feet 110 Ohm XLR". Are you using daft audiophool 'snake oil' cables ? I'd get rid of those straight away and use something sensible and reliable. Eeyore, you're frothing again, and for no reason. 110 ohm XLR cables are designed to be compatible with AES/EBU digital signals. They also work fine for microphones, although they tend to be stiff and thus a bit unruly to handle. But using them means you can use the same batch of cables for analog audio or digital signals without worrying that you might grab the wrong cable by mistake. I know, I know but I'm sure the OP has been bamboozled to pay over the odds for this 'magic cable' from a manufacturer that's been blessed by the audiophools. D-110 AES/EBU Balanced Digital Cable (XLR termination) 0.5 meter 79.00 1.0 meter 89.00 1.5 meter 99.00 2.0 meter 109.00 Each additional meter 16.50 http://www.silversonic.com/docs/prices.html#D110 I make that $142 ! Whereas all he needs is (for example) 101-066-001 5M £ 11.95 ($24) http://www.vdctrading.com/products.a...ionID=8&Page=5 Even their digital version is only £13.44 ($27) http://www.vdctrading.com/products.a...onID=8&Page=10 So he's paying around $115 simply to have the name DH Labs (which means nothing). Graham |
#75
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Ribbon Mic picking up Radio Frequency Interference
Paul Stamler wrote: "Eeyore" wrote " The clarity of an audio signal is greatly affected by the components power supply " is fairly close to a straight LIE. It's certainly deceptive marketing. The power supply *can* affects the sound but that's down to the internal *components* and circuit design. The power cable is NEVER responsible. Not entirely true, although nearly so. I once had to rebuild a piece of gear being used near a UHF-TV transmitter and, along with all the ferrite beads and ceramic discs needed to clean it up, I found it necessary to use a shielded power cord. It wasn't any SilverSonic thing, though, but one I bought from (I think) Mouser Electronics for $3.95. That is an extreme environment of course and indeed, any decent screened cable will do the job. Graham |
#76
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Ribbon Mic picking up Radio Frequency Interference
Richard Crowley wrote: "Eeyore" wrote ... Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? Same general reason every condensor microphone (conventional or electret) has a "head amp". i.e. impedance conversion (even if no signal gain). In the case of condenser the ultra-high impedance isn't practical to send down a conventional mic shielded pair. And in the case of the ribbon, the impedance is too low. No. That's not a problem at all. Or to look at it another way, there's too much current and not enough voltage for conventional mic circuits. The traditional way to solve the problem was to use a step-up transformer. For example Lundahl LL2912, 2913, 2914 It doesn't mean you have to have active circuitry in the mic itself though. Graham |
#77
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Ribbon Mic picking up Radio Frequency Interference
Richard Crowley wrote: "Eeyore" wrote ... Truth wrote: Eeyore wrote: It sounds like they've been pumping you full of nonsense. No they are correct. When my LCD monitor is on I can hear a definite hum or buzz. When I turn it off it goes away, so I turn it off while recording. That proves the sum total of nothing other than poor product design. I know, I'm a pro-audio designer and pretty expert in RF interference matters actually. Because the microphones use magnetism to function they are prone to these problems. Rubbish. The fact the mics have a magnet inside is totally and completely irrelevant to RF pickup. Where the hell do you get this crap from ? What is especially relevant by the way is inductance and 'loop area'. They sound good when they work, As some badly designed equipment (especially esoteric hi-fi) often does. Perhaps you are unaware that Royer has a rather good reputation on this side of the pond for making good products with what appears to be decent engineering and good customer relations, etc. There are more than enough vendors of shoddy or questionable equipment who are worthy of your rants, but I don't think Royer is among them. http://www.royerlabs.com/ I had other products in mind wrt that comment. Note the reference to hi-fi. Graham |
#78
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Ribbon Mic picking up Radio Frequency Interference
"Eeyore" wrote in message
... Scott Dorsey wrote: Eeyore wrote: Paul Stamler wrote: But Royer's comment that the mic can act as an antenna sounds to me like it's a known problem with these microphones. Absolutely. Why on earth did they do anything so daft as to give a ribbon a 'head amp' ? The head amp is really just a cathode follower. It has no gain, but it makes driving long cables easier and reduces perceived differences between preamps due to loading. Also it makes it possible to use a higher ratio transformer since the transformer has a fixed and known high-Z load. I still don't understand what's wrong with having the ribbon drive the cable. Nothing wrong with having the ribbon drive the cable; it's got a nice low impedance. But when the signal arrives at the preamp, that's when the signal hits the fan. In a separate post, you asked why ribbons might have this particular design characteristic. I suspect it's a legacy of history; the classic ribbon mic was originally designed to operate into a transformer which fed the grid of a vacuum tube with no terminating resistor. (Take a look at schematics for early RCA mic preamps.) Except for the capacitance of the tube and stray capacitance in the transformer, the impedance was very high. (Even the tube capacitance ceased to be an issue in some preamps where RCA used pentodes instead of triodes.) So the microphone's motor was designed with sufficient mechanical damping to provide the desired frequency response and damping. Add a lowish impedance across that motor, and now it's overdamped and the high-frequency response droops, which is what happens with classic ribbon mics like RCAs and their AEA clones when operated into modern preamps. (See Scott Dorsey's review, in "Recording", of the AEA preamp for a report on the very audible response differences he heard when using a classic ribbon into that high-Z-input preamp and more conventional modern circuits.) Royer's microphone designs are descended, technically, from classic ribbon designs, specifically the B&O ribbons which were popular in the early 1960s. (Royer has made changes and updates, but the basic motor design comes from the B&Os.) Rather than change a design which is basically a good one to match modern preamp inputs, Royer offers the option of using a buffer, either a FET or a tube, to take the element of preamp loading more-or-less out of the equation. In a way, the situation is the mirror image of similar issues with Shure SM57 mics; those were designed with *low* mechanical damping, with the expectation they'd feed a low preamp input impedance which provided lots of electrical damping. Those benefit from an extra loading resistor; classic ribbons benefit from a higher-input-Z preamp or a buffer. Except that the buffer may be introducing new problems, hence this thread. Peace, Paul |
#79
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Ribbon Mic picking up Radio Frequency Interference
"Eeyore" wrote in message
... "Eeyore" wrote Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the connection between the preamps and the sound card. What the heck is a "DH labs 12 feet 110 Ohm XLR". Are you using daft audiophool 'snake oil' cables ? I'd get rid of those straight away and use something sensible and reliable. Eeyore, you're frothing again, and for no reason. 110 ohm XLR cables are designed to be compatible with AES/EBU digital signals. They also work fine for microphones, although they tend to be stiff and thus a bit unruly to handle. But using them means you can use the same batch of cables for analog audio or digital signals without worrying that you might grab the wrong cable by mistake. I know, I know but I'm sure the OP has been bamboozled to pay over the odds for this 'magic cable' from a manufacturer that's been blessed by the audiophools. D-110 AES/EBU Balanced Digital Cable (XLR termination) 0.5 meter 79.00 1.0 meter 89.00 1.5 meter 99.00 2.0 meter 109.00 Each additional meter 16.50 http://www.silversonic.com/docs/prices.html#D110 I make that $142 ! Whereas all he needs is (for example) 101-066-001 5M £ 11.95 ($24) http://www.vdctrading.com/products.a...ionID=8&Page=5 Even their digital version is only £13.44 ($27) http://www.vdctrading.com/products.a...onID=8&Page=10 So he's paying around $115 simply to have the name DH Labs (which means nothing). Well, that does look to be the case. Markertek sells a 25' (~7.5 meters) AES digital cable for $37.95, with good Canare cable and Neutrik plugs, and lead-free to boot. So I do think he overpaid. Back to the RF questions. Peace, Paul |
#80
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Ribbon Mic picking up Radio Frequency Interference
Eeyore wrote:
Scott Dorsey wrote: The head amp is really just a cathode follower. It has no gain, but it makes driving long cables easier and reduces perceived differences between preamps due to loading. Also it makes it possible to use a higher ratio transformer since the transformer has a fixed and known high-Z load. I still don't understand what's wrong with having the ribbon drive the cable. There's some mention of it in Techniques of the Sound Studio. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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