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#1
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
I have a handheld recorder which does not have a "line in" socket. The
only input it has is a "mic" socket. The manufacturers sell a lead which is used to attenuate the "line out" from another device into my mic socket. I would rather make my own lead. Obviously I don't want to alter the frequency response. What components would I need and in what configuration would they need to be? |
#2
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
In article , Alex Coleman wrote:
I have a handheld recorder which does not have a "line in" socket. The only input it has is a "mic" socket. The manufacturers sell a lead which is used to attenuate the "line out" from another device into my mic socket. I would rather make my own lead. Obviously I don't want to alter the frequency response. What components would I need and in what configuration would they need to be? Put a 470 ohm resistor across the recorder input. Put a 10K ohm in series feeding the hot side of the input jack fed from the line out. Other side to common side of input jack. If the levels need changed, the ratio needs to be adjusted between the two resistors. 10k to 27K to reduce, 10K to 5K to increase. greg |
#3
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
"Alex Coleman" schreef in bericht ... I have a handheld recorder which does not have a "line in" socket. The only input it has is a "mic" socket. The manufacturers sell a lead which is used to attenuate the "line out" from another device into my mic socket. I would rather make my own lead. Obviously I don't want to alter the frequency response. What components would I need and in what configuration would they need to be? Specifications of mic inputs and line in- and outputs depends of the manufacturer. One I ever found says: mic input sensitivity 12uV max, input impedance 300-2k4 line input sensitivity 12uV min, input impedance 10k but there are much more possibilities. If you the specs of your recorder, you can calculate the resistor network you need. If you can't, you can experiment with the network below. +-----+-----+ | | | | | R2 .-. | |220k| | | | | | | | '-' | | | | | | | | | | R1 .-. .-. -+ 12k| | | |----- | | | | line out '-' '-'1k mic in | | -------+-----+------- created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de When the line out signal is too high, so when it is difficult to adjust the pot in the lower part, you can rise R2 up to 1M (try some values) and lower R1 to 10k. I don't expect the signal to be too week, but if it is you can make both resistors 22k. petrus bitbyter |
#4
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
The manufacturers sell a lead which is used to attenuate the "line out" from another device into my mic socket. I would rather make my own lead. Obviously I don't want to alter the frequency response. What components would I need and in what configuration would they need to be? Put a 470 ohm resistor across the recorder input. Put a 10K ohm in series feeding the hot side of the input jack fed from the line out. Other side to common side of input jack. If the levels need changed, the ratio needs to be adjusted between the two resistors. 10k to 27K to reduce, 10K to 5K to increase. A simple resistive pad is all you need. Here is a site that descibes several options in good detail. http://www.epanorama.net/circuits/line_to_mic.html Frequency response should not be a problem, but noise can be. The idea for good audio is to have as few amplifiers in the line as possible, and with the minimum amplification necessary. When you bring down a line level source with a resistive pad, you are essentially bringing the original signal closer to the noise level. Then, because you have a mic level input, you amplify the signal again (including the noise). It's not a problem for most applications, but then again, for a critical studio signal, it could be. Beachcomber |
#5
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
GregS spake thus:
In article , Alex Coleman wrote: I have a handheld recorder which does not have a "line in" socket. The only input it has is a "mic" socket. The manufacturers sell a lead which is used to attenuate the "line out" from another device into my mic socket. I would rather make my own lead. Obviously I don't want to alter the frequency response. What components would I need and in what configuration would they need to be? Put a 470 ohm resistor across the recorder input. Put a 10K ohm in series feeding the hot side of the input jack fed from the line out. Other side to common side of input jack. If the levels need changed, the ratio needs to be adjusted between the two resistors. 10k to 27K to reduce, 10K to 5K to increase. I don't see why you can't just put a single resistor between the line out and mike in. Since the mike input is lower impedance than the line output to start with, why would you need a load resistor; why not just something to reduce the voltage? -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#6
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
"David Nebenzahl" wrote in message .com... I don't see why you can't just put a single resistor between the line out and mike in. Yes you could if you knew the input impedance of the mic input. Or simply use trial and error. Since the mike input is lower impedance than the line output to start with, How do you know that? In fact it is not usually the case. Line *outputs* are often around 200 ohms or less, and mic inputs around 1k ohm or more. why would you need a load resistor; why not just something to reduce the voltage? That's just what a voltage divider does no matter how many resitors you use. In any case the performance of the mic amp on these units is usually very poor. Be prepared to be disapponted whatever lead you use. MrT. |
#7
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
"Mr.T" MrT@home wrote in message
"David Nebenzahl" wrote in message .com... I don't see why you can't just put a single resistor between the line out and mike in. Yes you could if you knew the input impedance of the mic input. Or simply use trial and error. Since the mike input is lower impedance than the line output to start with, How do you know that? In fact it is not usually the case. Line *outputs* are often around 200 ohms or less, and mic inputs around 1k ohm or more. why would you need a load resistor; why not just something to reduce the voltage? That's just what a voltage divider does no matter how many resitors you use. In any case the performance of the mic amp on these units is usually very poor. Be prepared to be disapponted whatever lead you use. If you go the series resistor route, also you can easily end up with a voltage divider with a high output impedance, which then exposes you to losses at high frequencies. Not a problem when the input impedance of of the equipment being driven is 5 K ohms, but a recipie for disaster when the input impedance of of the equipment being driven is 500 K ohms. |
#8
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
In article , David Nebenzahl wrote:
GregS spake thus: In article , Alex Coleman wrote: I have a handheld recorder which does not have a "line in" socket. The only input it has is a "mic" socket. The manufacturers sell a lead which is used to attenuate the "line out" from another device into my mic socket. I would rather make my own lead. Obviously I don't want to alter the frequency response. What components would I need and in what configuration would they need to be? Put a 470 ohm resistor across the recorder input. Put a 10K ohm in series feeding the hot side of the input jack fed from the line out. Other side to common side of input jack. If the levels need changed, the ratio needs to be adjusted between the two resistors. 10k to 27K to reduce, 10K to 5K to increase. I don't see why you can't just put a single resistor between the line out and mike in. Since the mike input is lower impedance than the line output to start with, why would you need a load resistor; why not just something to reduce the voltage? It gets you off to an approximate attenuation level, not guessing. greg |
#9
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
Arny Krueger spake thus:
"Mr.T" MrT@home wrote in message "David Nebenzahl" wrote in message rs.com... I don't see why you can't just put a single resistor between the line out and mike in. Yes you could if you knew the input impedance of the mic input. Or simply use trial and error. Since the mike input is lower impedance than the line output to start with, How do you know that? In fact it is not usually the case. Line *outputs* are often around 200 ohms or less, and mic inputs around 1k ohm or more. why would you need a load resistor; why not just something to reduce the voltage? That's just what a voltage divider does no matter how many resitors you use. In any case the performance of the mic amp on these units is usually very poor. Be prepared to be disapponted whatever lead you use. If you go the series resistor route, also you can easily end up with a voltage divider with a high output impedance, which then exposes you to losses at high frequencies. Not a problem when the input impedance of of the equipment being driven is 5 K ohms, but a recipie for disaster when the input impedance of of the equipment being driven is 500 K ohms. Yes, but--2 things: 1. Isn't the input impedance of the little recorder likely to be significantly less than 500 KΩ? 2. In any case, how would a mismatched voltage divider cause high frequency losses? (This is a request due to ignorance.) I don't see how a resistive network, with no L or C components, could affect frequency response at all. -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#10
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
"David Nebenzahl" wrote in message
.com Arny Krueger spake thus: "Mr.T" MrT@home wrote in message "David Nebenzahl" wrote in message .com... I don't see why you can't just put a single resistor between the line out and mike in. Yes you could if you knew the input impedance of the mic input. Or simply use trial and error. Since the mike input is lower impedance than the line output to start with, How do you know that? In fact it is not usually the case. Line *outputs* are often around 200 ohms or less, and mic inputs around 1k ohm or more. why would you need a load resistor; why not just something to reduce the voltage? That's just what a voltage divider does no matter how many resitors you use. In any case the performance of the mic amp on these units is usually very poor. Be prepared to be disapponted whatever lead you use. If you go the series resistor route, also you can easily end up with a voltage divider with a high output impedance, which then exposes you to losses at high frequencies. Not a problem when the input impedance of of the equipment being driven is 5 K ohms, but a recipie for disaster when the input impedance of of the equipment being driven is 500 K ohms. Yes, but--2 things: 1. Isn't the input impedance of the little recorder likely to be significantly less than 500 K?? Good design is about not taking unecessary risks. 2. In any case, how would a mismatched voltage divider cause high frequency losses? (This is a request due to ignorance.) I don't see how a resistive network, with no L or C components, could affect frequency response at all. The cable and gear downstream of the divider contributes the parallel C. |
#11
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
Arny Krueger spake thus:
"David Nebenzahl" wrote in message .com Arny Krueger spake thus: "Mr.T" MrT@home wrote in message .au "David Nebenzahl" wrote in message ters.com... I don't see why you can't just put a single resistor between the line out and mike in. Yes you could if you knew the input impedance of the mic input. Or simply use trial and error. Since the mike input is lower impedance than the line output to start with, How do you know that? In fact it is not usually the case. Line *outputs* are often around 200 ohms or less, and mic inputs around 1k ohm or more. why would you need a load resistor; why not just something to reduce the voltage? That's just what a voltage divider does no matter how many resitors you use. In any case the performance of the mic amp on these units is usually very poor. Be prepared to be disapponted whatever lead you use. If you go the series resistor route, also you can easily end up with a voltage divider with a high output impedance, which then exposes you to losses at high frequencies. Not a problem when the input impedance of of the equipment being driven is 5 K ohms, but a recipie for disaster when the input impedance of of the equipment being driven is 500 K ohms. Yes, but--2 things: 1. Isn't the input impedance of the little recorder likely to be significantly less than 500 K?? Good design is about not taking unecessary risks. For a company designing a product for sale, that would be a consideration. For a guy trying to get a signal into an el cheapo handheld recorder, I don't think it makes any difference. 2. In any case, how would a mismatched voltage divider cause high frequency losses? (This is a request due to ignorance.) I don't see how a resistive network, with no L or C components, could affect frequency response at all. The cable and gear downstream of the divider contributes the parallel C. What if the single resistor was right at the microphone plug? No significant C then, right? -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#12
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
"David Nebenzahl" wrote in message .com... The cable and gear downstream of the divider contributes the parallel C. What if the single resistor was right at the microphone plug? No significant C then, right? As Arny said, there is already some shunt capacitance in the box which you have no control over. MrT. |
#13
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
"David Nebenzahl" wrote in message
.com Arny Krueger spake thus: "David Nebenzahl" wrote in message .com Arny Krueger spake thus: "Mr.T" MrT@home wrote in message "David Nebenzahl" wrote in message .com... I don't see why you can't just put a single resistor between the line out and mike in. Yes you could if you knew the input impedance of the mic input. Or simply use trial and error. Since the mike input is lower impedance than the line output to start with, How do you know that? In fact it is not usually the case. Line *outputs* are often around 200 ohms or less, and mic inputs around 1k ohm or more. why would you need a load resistor; why not just something to reduce the voltage? That's just what a voltage divider does no matter how many resitors you use. In any case the performance of the mic amp on these units is usually very poor. Be prepared to be disapponted whatever lead you use. If you go the series resistor route, also you can easily end up with a voltage divider with a high output impedance, which then exposes you to losses at high frequencies. Not a problem when the input impedance of of the equipment being driven is 5 K ohms, but a recipie for disaster when the input impedance of of the equipment being driven is 500 K ohms. Yes, but--2 things: 1. Isn't the input impedance of the little recorder likely to be significantly less than 500 K?? Good design is about not taking unecessary risks. For a company designing a product for sale, that would be a consideration. For a guy trying to get a signal into an el cheapo handheld recorder, I don't think it makes any difference. I can't believe that so much air has been warmed (figuratively speaking) over a ten cent resistor. 2. In any case, how would a mismatched voltage divider cause high frequency losses? (This is a request due to ignorance.) I don't see how a resistive network, with no L or C components, could affect frequency response at all. The cable and gear downstream of the divider contributes the parallel C. What if the single resistor was right at the microphone plug? No significant C then, right? Not so, even equipment that is specifically designed to have low input capacitance like oscilliscopes and other test equipment, has input capacitances in the range of 15-35 pF. Equipment with high input impedance did not die with the days of the tube. Direct boxes are very common and by definition have very high input impedances. |
#14
Posted to alt.engineering.electrical,sci.electronics.equipment,rec.audio.tech,rec.audio.misc
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Attenuating "line out" into a mic socket
Alex Coleman writes:
I have a handheld recorder which does not have a "line in" socket. The only input it has is a "mic" socket. The manufacturers sell a lead which is used to attenuate the "line out" from another device into my mic socket. I would rather make my own lead. Obviously I don't want to alter the frequency response. What components would I need and in what configuration would they need to be? You can find example circuits for this at http://www.epanorama.net/circuits/line_to_mic.html -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/ |
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