Re: [Elecraft] Microphones for K2/3
Charles Harpole wrote: I see that now Elecraft is offering sale of a Heil K2 Pro Set mic/headphone unit, saying it is "optimized for K2." I assume that also means K3. Charles brings up a good point. What is it that makes any microphone "optimized" for any radio. Pin outs are obvious of course. - Impedance? - Bandwidth? - Signal Strength? John ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
Marketing. :) -- Julian, G4ILO K2 s/n: 392 K3 s/n: ??? G4ILO's Shack: www.g4ilo.com Ham-Directory: www.ham-directory.com On 9/5/07, John Huggins <[EMAIL PROTECTED]> wrote: > > Charles brings up a good point. What is it that makes any microphone > "optimized" for any radio. Pin outs are obvious of course. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
On Wed, 05 Sep 2007 06:53:40 -0400, John Huggins wrote: >What is it that makes any microphone >"optimized" for any radio. Pin outs are obvious of course. Many years ago, an international standards organization issued a poorly thought out standard for 2-way radio communications that, if followed, resulted in the bandwidth of transmitted audio being rolled off by 3-6 dB at 3 kHz. Because the higher audio frequencies (1-4 kHz) contribute the most to intelligibility, this resulted in reduced "talk power" and muddy audio if a mic with good (flat) frequency response is used. To compensate for this lousy standard, mic companies began building mics with a strong peak in their response around 3 kHz. This response peak is clearly visible in the response of mics like the Shure 450 -- there's a 10 dB peak at 3 kHz! Plug this mic into a pro sound system and it will sound really nasty, but connected to you ham rig it sounds just about right. Some ham transceivers provide a switchable peak in the audio response so that a pro mic with flat response can be used. The K2 does not. Another element of good communications audio (that is, good "talk power") is to limit the low frequency response so that transmitter power is not wasted on the bassy parts of speech. That's because these low frequencies contribute very little to intelligibility. A good communications circuit will roll off sharply on the low end somewhere between 250 and 400 Hz. It's easy to design this into ham gear, and it's also designed into a few mics. The EV 635A, for nearly 50 years a mainstay of broadcasting, rolls off at about 150 Hz. The K2 runs flat down to about 40 Hz, but can be modified to move the rolloff up to about 200 Hz by changing some capacitors and resistors. A mic also needs enough output voltage to drive the radio. This is not an issue with most ham rigs, but the K2 is a bit low on gain through the audio chain, so it takes a pretty "hot" mic to drive it well. Pro dynamic mics don't have enough output to drive it very well. Finally, the output impedance of the mic needs to be low enough that the input impedance of the radio doesn't load it down. Mics are not designed to be "loaded" (that is, terminated). They are designed to work into an impedance at least 5-10 times their own source impedance. The input impedance of the K2 is on the order of 600 ohms, which is on the low side for a pro mic (typically 150 ohms output impedance). This is easy to change with a few resistors. Summarizing -- for use with the K2, a mic needs relatively high output, should have an output impedance lower than about 100 ohms, should have a pronounced response peak around 3 kHz, and should be rolled off around 250-400 Hz on the low end. 73, Jim Brown K9YC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
John and Charles: The Heil Prosets with the HC-4 or HC-5 elements don't have quite enough output to drive the K2 without either an external preamp or tweaking of the K2's internal circuitry. The version with the electret element seems to work better with the K2. I believe the Heil K2 Proset is essentially the version with the electret element, but I'm not 100% certain on that matter. All Prosets require an adapter to match your particular mic jack configuration, so that is not a factor. No idea about the K3. 73's, John AA0VE Charles Harpole wrote: I see that now Elecraft is offering sale of a Heil K2 Pro Set mic/headphone unit, saying it is "optimized for K2." I assume that also means K3. Charles brings up a good point. What is it that makes any microphone "optimized" for any radio. Pin outs are obvious of course. - Impedance? - Bandwidth? - Signal Strength? John ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
John and all, You are correct that 'Heil Proset' by itself does not adequately describe the microphone. As is the case with all Heil mics, one must also be specific about the mic element used. The K2 works best with an electret element because they have higher output levels. The K3 FAQ pages indicate that it has adequate mic gain to handle the lower output Heil HC4 and HC5 elements. The Heil Proset K2 can be used with either the K2 or the K3, and it comes with the Elecraft adapter. 73, Don W3FPR John R. Lonigro wrote: John and Charles: The Heil Prosets with the HC-4 or HC-5 elements don't have quite enough output to drive the K2 without either an external preamp or tweaking of the K2's internal circuitry. The version with the electret element seems to work better with the K2. I believe the Heil K2 Proset is essentially the version with the electret element, but I'm not 100% certain on that matter. All Prosets require an adapter to match your particular mic jack configuration, so that is not a factor. No idea about the K3. 73's, John AA0VE ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
Thanks for the information all. So... I guess hooking up a D104 straight to K2 is not going to work out so well. Yes I know this is like putting tail fins on a Ford Taurus, but the kids really dig talking into a mic like that during times we promote ham radio. The D104 with my old Kenwood TS-520 still receives great audio reports and I would like to continue that tradition in some way with new gear. Crazy? John Don Wilhelm wrote: John and all, You are correct that 'Heil Proset' by itself does not adequately describe the microphone. As is the case with all Heil mics, one must also be specific about the mic element used. The K2 works best with an electret element because they have higher output levels. The K3 FAQ pages indicate that it has adequate mic gain to handle the lower output Heil HC4 and HC5 elements. The Heil Proset K2 can be used with either the K2 or the K3, and it comes with the Elecraft adapter. 73, Don W3FPR John R. Lonigro wrote: John and Charles: The Heil Prosets with the HC-4 or HC-5 elements don't have quite enough output to drive the K2 without either an external preamp or tweaking of the K2's internal circuitry. The version with the electret element seems to work better with the K2. I believe the Heil K2 Proset is essentially the version with the electret element, but I'm not 100% certain on that matter. All Prosets require an adapter to match your particular mic jack configuration, so that is not a factor. No idea about the K3. 73's, John AA0VE ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
Never had a problem John getting full rated PEP output from K2/100 #3255 using the HC-4 and HC-5 elements in the Heil ProSet Plus headset without an external preamp, but I don't use the K2/100's VOX. If I used VOX a little more audio gain would be required in the VOX circuit, but additional audio gain between the mic elements and modulator would result in overdrive. Perhaps my K2/100 is a positive tolerance version. 73, Geoff GM4ESD John R. Lonigro <[EMAIL PROTECTED]> wrote: John and Charles: The Heil Prosets with the HC-4 or HC-5 elements don't have quite enough output to drive the K2 without either an external preamp or tweaking of the K2's internal circuitry. The version with the electret element seems to work better with the K2. I believe the Heil K2 Proset is essentially the version with the electret element, but I'm not 100% certain on that matter. All Prosets require an adapter to match your particular mic jack configuration, so that is not a factor. No idea about the K3. 73's, John AA0VE ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
Geoffrey Mackenzie-Kennedy wrote: Never had a problem John getting full rated PEP output from K2/100 #3255 using the HC-4 and HC-5 elements in the Heil ProSet Plus headset without an external preamp, but I don't use the K2/100's VOX. If I used VOX a little more audio gain would be required in the VOX circuit, but additional audio gain between the mic elements and modulator would result in overdrive. Perhaps my K2/100 is a positive tolerance version. Interesting point, as I have that same issue with my Heil ProSet (HC5) and my Kenwood TS-2000. The rig has more than adequate modulation with this mic, but not enough gain in the VOX circuit to make VOX usable. Seems to me that the gain through these two audio paths ought to be proportionate in a good design -- i.e., if max modulation gain is just enough for full modulation, then max VOX amp gain should be just enough for effortless VOX operation. Bill W5WVO 73, Geoff GM4ESD John R. Lonigro <[EMAIL PROTECTED]> wrote: John and Charles: The Heil Prosets with the HC-4 or HC-5 elements don't have quite enough output to drive the K2 without either an external preamp or tweaking of the K2's internal circuitry. The version with the electret element seems to work better with the K2. I believe the Heil K2 Proset is essentially the version with the electret element, but I'm not 100% certain on that matter. All Prosets require an adapter to match your particular mic jack configuration, so that is not a factor. No idea about the K3. 73's, John AA0VE ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
John, If your D104 is an older one with the high impedance crystal or ceramic element, yes it will not work so well (if at all). There was an article in QST about a year ago with a circuit design that had a very high impedance input and the low impedance output required by modern day radios, although a transformer with the right ratio should work too. Another alternative is to change the element in the D104. Heil offers a kit to do just that - check www.heilsound.com for info. My D104 with an HC5 element draws comments from time to time. 73, Don W3FPR John Huggins wrote: Thanks for the information all. So... I guess hooking up a D104 straight to K2 is not going to work out so well. Yes I know this is like putting tail fins on a Ford Taurus, but the kids really dig talking into a mic like that during times we promote ham radio. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
I am pretty sure that there are a couple of very simple circuits in "W1FB's Design Notebook" that specifically use the "D104 -> modern_radio" as an example. Greg KI4MMM K2 #6100 On Sep 6, 2007, at 1:29 PM, Don Wilhelm wrote: John, If your D104 is an older one with the high impedance crystal or ceramic element, yes it will not work so well (if at all). There was an article in QST about a year ago with a circuit design that had a very high impedance input and the low impedance output required by modern day radios, although a transformer with the right ratio should work too. Another alternative is to change the element in the D104. Heil offers a kit to do just that - check www.heilsound.com for info. My D104 with an HC5 element draws comments from time to time. 73, Don W3FPR John Huggins wrote: Thanks for the information all. So... I guess hooking up a D104 straight to K2 is not going to work out so well. Yes I know this is like putting tail fins on a Ford Taurus, but the kids really dig talking into a mic like that during times we promote ham radio. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Microphones for K2/3
Thank you for the hints. Thanks to your and other's comments on the Elecraft list I have found numerous good examples with some as minimalistic as a FET + passives all the way to a good Instrumentation Amp + passives. This has inspired me to create a circuit based more on the modern In-Amp method leaving the only question of what the input impedance and range of typical radio mic inputs. Plus a survey of what voltage and current are available on the mic connector helps design for the most radios. In support of this I am scoring some wins on D104 mics on Ebay which are available on the cheap. Fun stuff... perhaps I will make this available as a "kit" for fellow D104 freaks. John Greg Derda wrote: I am pretty sure that there are a couple of very simple circuits in "W1FB's Design Notebook" that specifically use the "D104 -> modern_radio" as an example. Greg KI4MMM K2 #6100 On Sep 6, 2007, at 1:29 PM, Don Wilhelm wrote: John, If your D104 is an older one with the high impedance crystal or ceramic element, yes it will not work so well (if at all). There was an article in QST about a year ago with a circuit design that had a very high impedance input and the low impedance output required by modern day radios, although a transformer with the right ratio should work too. Another alternative is to change the element in the D104. Heil offers a kit to do just that - check www.heilsound.com for info. My D104 with an HC5 element draws comments from time to time. 73, Don W3FPR John Huggins wrote: Thanks for the information all. So... I guess hooking up a D104 straight to K2 is not going to work out so well. Yes I know this is like putting tail fins on a Ford Taurus, but the kids really dig talking into a mic like that during times we promote ham radio. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
