Re: [Elecraft] Mic and headphone
On 4/14/2014 4:46 PM, Harry_Yingst wrote: Phone lines are Typically 600 ohms Actually, the Zo of phone lines at radio frequencies is about 80 ohms, and varies widely with frequency in the audio spectrum. That characteristic is determined by the diameter, spacing, and insulation of the twisted pairs used to carry the signal. They have not been 600 ohms for at least 75 years. More than 40 years ago, it was standard practice to equalize broadcast lines for extended frequency response over relatively short paths, and transformers were used to step that impedance up to the 600 ohms used by older broadcast equipment. But the broadcast and pro audio world abandoned 600 ohms as a standard about 50 years ago. Modern audio circuits (since we converted from hollow state to solid state) use low impedance sources to drive high impedance imputs, there is no impedance matching except to the extent that the load impedance must be high enough that it does not draw any more current than the output stage is designed to provide. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Mic and headphone
Actually, the network termination impedance for two wire phone lines is important, as it is an important parameter in the design of the two to four wire hybrid. http://www1.btwebworld.com/sinet/351v4p5.pdf gives specifications for the UK network, which are somewhat higher than 600 ohms. Note these are the system values at audio frequencies; they are not the characteristic impedance of the line. The line will typically be too short for that to be significant. -- David Woolley Owner K2 06123 On 15/04/14 07:37, Jim Brown wrote: On 4/14/2014 4:46 PM, Harry_Yingst wrote: Phone lines are Typically 600 ohms Actually, the Zo of phone lines at radio frequencies is about 80 ohms, and varies widely with frequency in the audio spectrum. That characteristic is determined by the diameter, spacing, and insulation of the twisted pairs used to carry the signal. They have not been 600 ohms for at least 75 years. More than 40 years ago, it was standard practice __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Mic and headphone
On 4/15/2014 1:36 PM, David Woolley wrote: Note these are the system values at audio frequencies; they are not the characteristic impedance of the line. The line will typically be too short for that to be significant. Yes and no. We discussed this a week or so ago. Zo is not a constant, nor is it resistive at most frequencies. See http://k9yc.com/TransLines-LowFreq.pdf A telephone line may, indeed, too short to exhibit transmission line properties at audio frequencies, but it will certainly behave as a transmission line when it carries DSL, which has spectrum extending well into the MHz range. And a line several miles long WILL exhibit transmission line properties at high audio frequencies. Thanks for the link to the document showing the termination. What that network is doing is to approximately match to the varying Zo of the line at audio frequencies, and to equalize the propagation delay shown in Fig 1 and Fig 2 in my link. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Mic and headphone
Phone lines are Typically 600 ohms -- View this message in context: http://elecraft.365791.n2.nabble.com/Mic-and-headphone-tp7585125p7587248.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Mic and headphone
The Plantronics headset is normally inserted in the cord between the telephone and its handset, which does use all 4 wires, like this: http://en.wikipedia.org/wiki/File:RJ9_Handset_diagram.svg Don't know about impedance/level-matching with the K3 73, ~iain / N6ML On Wed, Mar 5, 2014 at 5:13 AM, Don Wilhelm w3...@embarqmail.com wrote: The complexity may involve sorting out the headphone connection from the mic while keeping feedback away. Telephone uses only a single pair wire in all installations I am familiar with. Yes, there are 4 wires in the typical phone jack and cable, but that will handle 2 lines. 73, Don W3FPR On 3/4/2014 10:37 PM, N5AG wrote: Thanks Don. I probably am worried about nothing. I know some others using this setup on Kenwood and Flex. Their's seemed a little more complex. That is the reason for the question. Allen Griffith On Tuesday, March 4, 2014 7:33 PM, Don Wilhelm-4 [via Elecraft] ml-node+s365791n7585134...@n2.nabble.com wrote: Allen, Most modern audio output stages are low impedance sources, and there is no need to match impedances. Do you think about matching impedances when you plug something into a power mains wall receptacle? Likely not, because the AC mains is a low impedance source and will deliver whatever the device needs. Your headphones are similar - with a low source impedance driver, you don't have to worry about it, just adjust the AF gain to a comfortable level. More power will be delivered to a low impedance device, but headphones do not require much power. The microphone is similar. It is a relatively low impedance source, and it is operating into a relatively high impedance device (1k to 10k for modern transceivers) and the voltage produced is the important parameter. Yes, high impedance microphones may not give the proper frequency response curve, but other than that, no impedance matching is normally required. Modern microphones are in the range of 200 to 600 ohms driving impedance. I suspect yours is also in that range. 73, Don W3FPR On 3/4/2014 7:12 PM, N5AG wrote: Has anyone wired up a Plantronics CS50 Telephone headset system to the K3? The Plantronics CS50 system is composed of a base unit that transmits and receives in full duplex to a small headset that is worn and gives the capability to transmit and receive up to 300 feet. The system uses 900 mhz to communicate between the base and the headset. The base unit normally would plug in to a land line base telephone using the standard four wire (two pair) found in most home telephone installs. I need recommendations on wiring the Plantronics CS50 base unit to the back panel mic and phone connections with the standard four wire line from the Plantronics base. Does the K3 have the ability via menu selection to match impedances for the mic and audio hook up stated above or must the matching be done in the interface between the Plantronics base and the K3? __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html If you reply to this email, your message will be added to the discussion below:http://elecraft.365791.n2.nabble.com/Mic-and-headphone-tp7585125p7585134.html To unsubscribe from Mic and headphone, click here. NAML -- View this message in context: http://elecraft.365791.n2.nabble.com/Mic-and-headphone-tp7585125p7585139.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Mic and headphone
On 3/4/2014 5:32 PM, Don Wilhelm wrote: The microphone is similar. It is a relatively low impedance source, and it is operating into a relatively high impedance device (1k to 10k for modern transceivers) and the voltage produced is the important parameter. Yes, high impedance microphones may not give the proper frequency response curve, but other than that, no impedance matching is normally required. Modern microphones are in the range of 200 to 600 ohms driving impedance. I suspect yours is also in that range. Good advice. Almost ten years ago, I bought what was probably a Plantronics salesman's sample kit of five different combo headset mics. I cut the connectors off of them and installed my own XL-connectors, then made adapters to go from the mics to the radios that I owned. The first task with each headset was to determine which wires went to the earphone and which to the mic. I did that simply by listening to the earset as I measured between wires with an ohmeter. I don't remember how I figured out which wire was common, but I did. :) In each adapter that I built, I added a suitable resistor between the bias terminal on the rig and mic input. Once I had done that, every headset/mic worked with every radio. Some were more comfortable than others, but all got good audio reports. All of that was long before the K3 even existed. But with the K3, all that is needed is to figure out which wire is which, connect them to the K3, and turn on the bias. They are all electret mics, and electret mics tend to be fairly hot (that is, fairly high output voltage). 73, Jim K9YC . __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Mic and headphone
The complexity may involve sorting out the headphone connection from the mic while keeping feedback away. Telephone uses only a single pair wire in all installations I am familiar with. Yes, there are 4 wires in the typical phone jack and cable, but that will handle 2 lines. 73, Don W3FPR On 3/4/2014 10:37 PM, N5AG wrote: Thanks Don. I probably am worried about nothing. I know some others using this setup on Kenwood and Flex. Their's seemed a little more complex. That is the reason for the question. Allen Griffith On Tuesday, March 4, 2014 7:33 PM, Don Wilhelm-4 [via Elecraft] ml-node+s365791n7585134...@n2.nabble.com wrote: Allen, Most modern audio output stages are low impedance sources, and there is no need to match impedances. Do you think about matching impedances when you plug something into a power mains wall receptacle? Likely not, because the AC mains is a low impedance source and will deliver whatever the device needs. Your headphones are similar - with a low source impedance driver, you don't have to worry about it, just adjust the AF gain to a comfortable level. More power will be delivered to a low impedance device, but headphones do not require much power. The microphone is similar. It is a relatively low impedance source, and it is operating into a relatively high impedance device (1k to 10k for modern transceivers) and the voltage produced is the important parameter. Yes, high impedance microphones may not give the proper frequency response curve, but other than that, no impedance matching is normally required. Modern microphones are in the range of 200 to 600 ohms driving impedance. I suspect yours is also in that range. 73, Don W3FPR On 3/4/2014 7:12 PM, N5AG wrote: Has anyone wired up a Plantronics CS50 Telephone headset system to the K3? The Plantronics CS50 system is composed of a base unit that transmits and receives in full duplex to a small headset that is worn and gives the capability to transmit and receive up to 300 feet. The system uses 900 mhz to communicate between the base and the headset. The base unit normally would plug in to a land line base telephone using the standard four wire (two pair) found in most home telephone installs. I need recommendations on wiring the Plantronics CS50 base unit to the back panel mic and phone connections with the standard four wire line from the Plantronics base. Does the K3 have the ability via menu selection to match impedances for the mic and audio hook up stated above or must the matching be done in the interface between the Plantronics base and the K3? __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html If you reply to this email, your message will be added to the discussion below:http://elecraft.365791.n2.nabble.com/Mic-and-headphone-tp7585125p7585134.html To unsubscribe from Mic and headphone, click here. NAML -- View this message in context: http://elecraft.365791.n2.nabble.com/Mic-and-headphone-tp7585125p7585139.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Mic and headphone
I am unable to find any info on the impedance of the Plantronics CS50. I have often wanted to try a CS50, but I often use both receivers, one in each ear and the SC50 is mono and only one ear. Good luck with your efforts. You may just plug it in and give it a try, before you go worrying if it will be a problem. here are some links with info that may prove helpful... from K3 Owner's man D10.pdf found here: http://www.elecraft.com/manual/E740107%20K3%20Owner%27s%20man%20D10.pdf === page 20 MIC (rear panel) MONO; hi- or low-Z This jack accommodates an electret or dynamic mic. Use MAIN:MIC SEL to select the rear panel mic (RP). Tap 1 to turn on Low or High mic gain range. Tap 2 to turn bias on/off (see pg. 28 for recommendations based on mic type). For the front-panel mic only, additional microphone gain can be enabled by tapping 3 . Use this only for very low-output mics. The mic’s PTT signal, if used, must be routed to either the PTT IN jack or the PTT line on the ACC connector (pg. 18). page 52 MIC SEL Mic/line transmit audio source, mic gain range, and mic bias. Source selections: FP (front panel 8-pin MIC jack), RP (rear panel 3.5 mm MIC jack), and LINE IN (rear-panel LINE IN jack). Tap 1 to toggle between .Low and .High mic gain range for the selected mic. ] Tap 2 to turn mic BIAS on/off (turn on for electric mics). For the front-panel mic only, tap 3 to turn on an additional gain stage. Use this only with very low-output mics. An apostrophe will appear after the H, e.g. H’. from Elecraft K3 Schematics found here: http://www.elecraft.com/manual/K3_Schematics_Jun_2010.pdf page 12 KIO3 Main, Sheet 2 page 13 KIO3: Audio IO Board shows the rear mic inputs keep us informed of your progress Griff -- GB 73 K5OAI Sam Morgan On 3/4/2014 6:12 PM, N5AG wrote: Has anyone wired up a Plantronics CS50 Telephone headset system to the K3? The Plantronics CS50 system is composed of a base unit that transmits and receives in full duplex to a small headset that is worn and gives the capability to transmit and receive up to 300 feet. The system uses 900 mhz to communicate between the base and the headset. The base unit normally would plug in to a land line base telephone using the standard four wire (two pair) found in most home telephone installs. I need recommendations on wiring the Plantronics CS50 base unit to the back panel mic and phone connections with the standard four wire line from the Plantronics base. Does the K3 have the ability via menu selection to match impedances for the mic and audio hook up stated above or must the matching be done in the interface between the Plantronics base and the K3? Thanks for any help, Allen Griffith N5AG K3 #03547 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Mic and headphone
Allen, Most modern audio output stages are low impedance sources, and there is no need to match impedances. Do you think about matching impedances when you plug something into a power mains wall receptacle? Likely not, because the AC mains is a low impedance source and will deliver whatever the device needs. Your headphones are similar - with a low source impedance driver, you don't have to worry about it, just adjust the AF gain to a comfortable level. More power will be delivered to a low impedance device, but headphones do not require much power. The microphone is similar. It is a relatively low impedance source, and it is operating into a relatively high impedance device (1k to 10k for modern transceivers) and the voltage produced is the important parameter. Yes, high impedance microphones may not give the proper frequency response curve, but other than that, no impedance matching is normally required. Modern microphones are in the range of 200 to 600 ohms driving impedance. I suspect yours is also in that range. 73, Don W3FPR On 3/4/2014 7:12 PM, N5AG wrote: Has anyone wired up a Plantronics CS50 Telephone headset system to the K3? The Plantronics CS50 system is composed of a base unit that transmits and receives in full duplex to a small headset that is worn and gives the capability to transmit and receive up to 300 feet. The system uses 900 mhz to communicate between the base and the headset. The base unit normally would plug in to a land line base telephone using the standard four wire (two pair) found in most home telephone installs. I need recommendations on wiring the Plantronics CS50 base unit to the back panel mic and phone connections with the standard four wire line from the Plantronics base. Does the K3 have the ability via menu selection to match impedances for the mic and audio hook up stated above or must the matching be done in the interface between the Plantronics base and the K3? __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Mic and headphone
Thanks Don. I probably am worried about nothing. I know some others using this setup on Kenwood and Flex. Their's seemed a little more complex. That is the reason for the question. Allen Griffith On Tuesday, March 4, 2014 7:33 PM, Don Wilhelm-4 [via Elecraft] ml-node+s365791n7585134...@n2.nabble.com wrote: Allen, Most modern audio output stages are low impedance sources, and there is no need to match impedances. Do you think about matching impedances when you plug something into a power mains wall receptacle? Likely not, because the AC mains is a low impedance source and will deliver whatever the device needs. Your headphones are similar - with a low source impedance driver, you don't have to worry about it, just adjust the AF gain to a comfortable level. More power will be delivered to a low impedance device, but headphones do not require much power. The microphone is similar. It is a relatively low impedance source, and it is operating into a relatively high impedance device (1k to 10k for modern transceivers) and the voltage produced is the important parameter. Yes, high impedance microphones may not give the proper frequency response curve, but other than that, no impedance matching is normally required. Modern microphones are in the range of 200 to 600 ohms driving impedance. I suspect yours is also in that range. 73, Don W3FPR On 3/4/2014 7:12 PM, N5AG wrote: Has anyone wired up a Plantronics CS50 Telephone headset system to the K3? The Plantronics CS50 system is composed of a base unit that transmits and receives in full duplex to a small headset that is worn and gives the capability to transmit and receive up to 300 feet. The system uses 900 mhz to communicate between the base and the headset. The base unit normally would plug in to a land line base telephone using the standard four wire (two pair) found in most home telephone installs. I need recommendations on wiring the Plantronics CS50 base unit to the back panel mic and phone connections with the standard four wire line from the Plantronics base. Does the K3 have the ability via menu selection to match impedances for the mic and audio hook up stated above or must the matching be done in the interface between the Plantronics base and the K3? __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html If you reply to this email, your message will be added to the discussion below:http://elecraft.365791.n2.nabble.com/Mic-and-headphone-tp7585125p7585134.html To unsubscribe from Mic and headphone, click here. NAML -- View this message in context: http://elecraft.365791.n2.nabble.com/Mic-and-headphone-tp7585125p7585139.html Sent from the Elecraft mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
