K3 - Splitting main/sub audio to 2 headphones
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I want to have a second op listening to the sub rx on a separate pair of phones (for 6m trophy, so same band). I've strung together 2 stereo sockets with one fed from the right and the other from the left side of the front panel phone output and this seems to works well. With the channels linked I get Main in both ears in one headphone set and Sub in both ears in the other, and when the sub rx is off there is Main in both.
I'll be using a Yamaha CM-500 and a gaming headset so I'm wondering if I should be loading the audio with 2 headphones without any buffering etc. A cheap mixer with separate amps would be good and may give better volume control although the gamers have an inline volume control on the lead. A quick search however hasn't found a mixer that separates the input channels..... Ideas/comments? 73, Stew, GW0ETF ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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Stew,
You should have no problems with paralleling 2 headphones on the audio output of the K3, with no need for any external mixer. If there is a significant difference in the response (SPL) of the two headphones, that may present a volume problem, in which case, some secondary amplification may be required for one or the other set of headphones. Since the gaming headset has a volume control, that alone may be sufficient - try it and see what the result may be. 73, Don W3FPR On 5/31/2014 5:20 AM, Stewart Rolfe wrote: > I want to have a second op listening to the sub rx on a separate pair of phones (for 6m trophy, so same band). I've strung together 2 stereo sockets with one fed from the right and the other from the left side of the front panel phone output and this seems to works well. With the channels linked I get Main in both ears in one headphone set and Sub in both ears in the other, and when the sub rx is off there is Main in both. > > I'll be using a Yamaha CM-500 and a gaming headset so I'm wondering if I should be loading the audio with 2 headphones without any buffering etc. A cheap mixer with separate amps would be good and may give better volume control although the gamers have an inline volume control on the lead. A quick search however hasn't found a mixer that separates the input channels..... > > ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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On 2014-06-01 1:02 AM, Don Wilhelm wrote:> > > You should have no problems with paralleling 2 headphones on the > audio output of the K3, with no need for any external mixer. I would not risk it. The K3 headphone amplifier is only rated for 105 mW at 16 Ohms. Both power dissipation (heat) and distortion rise significantly as the load impedance drops and the output power increase. I would recommend use of a headphone amp - even without individual balance capabilities - and individual adapter cables for each user. Connect tip on the amplifier to both tip and sleeve on the headphones for the operator using the main RX and connect ring to tip and ring for the operator using the sub RX. Since the outputs of the headphone amplifier/splitters are generally isolated, one could even make cables with a 1K or 5K pot to create their own "balance/mix" control. 73, ... Joe, W4TV On 2014-06-01 1:02 AM, Don Wilhelm wrote: > Stew, > > You should have no problems with paralleling 2 headphones on the audio > output of the K3, with no need for any external mixer. If there is a > significant difference in the response (SPL) of the two headphones, that > may present a volume problem, in which case, some secondary > amplification may be required for one or the other set of headphones. > Since the gaming headset has a volume control, that alone may be > sufficient - try it and see what the result may be. > > 73, > Don W3FPR > > On 5/31/2014 5:20 AM, Stewart Rolfe wrote: >> I want to have a second op listening to the sub rx on a separate pair >> of phones (for 6m trophy, so same band). I've strung together 2 stereo >> sockets with one fed from the right and the other from the left side >> of the front panel phone output and this seems to works well. With the >> channels linked I get Main in both ears in one headphone set and Sub >> in both ears in the other, and when the sub rx is off there is Main in >> both. >> >> I'll be using a Yamaha CM-500 and a gaming headset so I'm wondering if >> I should be loading the audio with 2 headphones without any buffering >> etc. A cheap mixer with separate amps would be good and may give >> better volume control although the gamers have an inline volume >> control on the lead. A quick search however hasn't found a mixer that >> separates the input channels..... >> >> > > ______________________________________________________________ > 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 > Message delivered to [hidden email] > 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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On 6/1/2014 7:45 AM, Joe Subich, W4TV wrote:
>> You should have no problems with paralleling 2 headphones on the >> audio output of the K3, with no need for any external mixer. > > I would not risk it. The K3 headphone amplifier is only rated for 105 > mW at 16 Ohms. I agree with Don that it's perfectly fine to parallel two sets of headphones on the output of a K3. The load impedance of most modern headphones is much greater than 16 ohms. 73, Jim K9YC ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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On 2014-06-01 2:11 PM, Jim Brown wrote: > I agree with Don that it's perfectly fine to parallel two sets of > headphones on the output of a K3. The load impedance of most modern > headphones is much greater than 16 ohms. You can't guarantee that with any two random headphones - my shack has headphones anywhere from 8 Ohms to 200 Ohms. Paralleling headphones of with differing impedance and sensitivity will result in one operator getting too much or too little audio and may require gain high enough to result in excess distortion or dissipation. 73, ... Joe, W4TV On 2014-06-01 2:11 PM, Jim Brown wrote: > On 6/1/2014 7:45 AM, Joe Subich, W4TV wrote: >>> You should have no problems with paralleling 2 headphones on the >>> audio output of the K3, with no need for any external mixer. >> >> I would not risk it. The K3 headphone amplifier is only rated for 105 >> mW at 16 Ohms. > > I agree with Don that it's perfectly fine to parallel two sets of > headphones on the output of a K3. The load impedance of most modern > headphones is much greater than 16 ohms. > > 73, Jim K9YC > ______________________________________________________________ > 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 > Message delivered to [hidden email] > 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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On 6/1/2014 11:29 AM, Joe Subich, W4TV wrote:
> You can't guarantee that with any two random headphones - my shack has > headphones anywhere from 8 Ohms to 200 Ohms. I would change that. Simple Ohms Law suggests that's a very bad idea, for reasons noted in the next sentence. > Paralleling headphones > of with differing impedance and sensitivity will result in one operator > getting too much or too little audio and may require gain high enough > to result in excess distortion or dissipation. That may be true, and is the only negative for paralleling them. But it also depends on the voltage sensitivity of the headphones involved. ______________________________________________________________ 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 Message delivered to [hidden email] |
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In reply to this post by Joe Subich, W4TV-4
I got a "3-channel headphone volume booster" at RS for $7.95 [IIRC].
Runs on 2 AA's, one gozinto, three gozoutofs. The audio on my KX1 and K2 is too low for my compromised hearing. 73, Fred K6DGW - Northern California Contest Club - CU in the 2014 Cal QSO Party 4-5 Oct 2014 - www.cqp.org On 6/1/2014 11:48 AM, Walter Underwood wrote: > I've used this headphone distribution amp, it has jacks and pots for > four listeners. $25. > > http://www.amazon.com/Behringer-HA400-4-Channel-Stereo-Headphone/dp/B000KIPT30/ ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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In reply to this post by Jim Brown-10
On 2014-06-01 2:39 PM, Jim Brown wrote: >> Paralleling headphones of with differing impedance and sensitivity >> will result in one operator getting too much or too little audio >> and may require gain high enough to result in excess distortion or >> dissipation. > > That may be true, and is the only negative for paralleling them. But > it also depends on the voltage sensitivity of the headphones > involved. As I implied in my statement - one can have differing sensitivities even with headphones of he same nominal impedance and even differing sensitivity between older and newer units of the same manufacturer and model. That's why the safest course of action is to always use an amplified splitter with individual gain controls. 73, ... Joe, W4TV On 2014-06-01 2:39 PM, Jim Brown wrote: > On 6/1/2014 11:29 AM, Joe Subich, W4TV wrote: >> You can't guarantee that with any two random headphones - my shack has >> headphones anywhere from 8 Ohms to 200 Ohms. > > I would change that. Simple Ohms Law suggests that's a very bad idea, > for reasons noted in the next sentence. > >> Paralleling headphones >> of with differing impedance and sensitivity will result in one operator >> getting too much or too little audio and may require gain high enough >> to result in excess distortion or dissipation. > > That may be true, and is the only negative for paralleling them. But it > also depends on the voltage sensitivity of the headphones involved. > ______________________________________________________________ > 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 > Message delivered to [hidden email] > 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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In reply to this post by Joe Subich, W4TV-4
On 6/1/14 at 7:45 AM, [hidden email] (Joe Subich, W4TV) wrote:
>On 2014-06-01 1:02 AM, Don Wilhelm wrote:> >> >>You should have no problems with paralleling 2 headphones on the >>audio output of the K3, with no need for any external mixer. > >I would not risk it. The K3 headphone amplifier is only rated for >105 mW at 16 Ohms. Both power dissipation (heat) and distortion >rise significantly as the load impedance drops and the output power >increase. I had this problem when installing a FTM-10 in my Mazda Miata. I placed the speakers in series so as not to overload the audio amplifiers. The output level is somewhat marginal when traveling at freeway speeds with the top down, but so is conversation with a passenger. 73, Bill AE6JV ----------------------------------------------------------------------- Bill Frantz | Since the IBM Selectric, keyboards have gotten 408-356-8506 | steadily worse. Now we have touchscreen keyboards. www.pwpconsult.com | Can we make something even worse? ______________________________________________________________ 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 Message delivered to [hidden email] |
Re: K3 - Splitting main/sub audio to 2 headphones
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On 6/2/2014 11:03 AM, Bill Frantz wrote:
> I had this problem when installing a FTM-10 in my Mazda Miata. I > placed the speakers in series so as not to overload the audio > amplifiers. The output level is somewhat marginal when traveling at > freeway speeds with the top down, but so is conversation with a > passenger. That was a mistake. Audio power amps have very low source Z, typically <0.05 ohms, and most are designed to drive a 4 ohm load. In other words, they are a constant voltage source. That means they will easily drive two 8 ohm loudspeakers. For all practical purposes, the power delivered to each loudspeaker is the same as if it were the only one connected. The limit on this is the power supply -- as you approach the minimum rated impedance and high signal levels, the power amp may clip a dB or so lower. When you wire the loudspeakers in series, that constant output voltage divides between them as a function of their impedance AT EVERY FREQUENCY, and the impedance of ANY dynamic loudspeaker varies over a range of at least 50:1 with frequency. The rated impedance of a loudspeaker is the minimum value of the impedance, which occurs for most loudspeakers in its lower midrange. Which brings us to the second problem with your hookup -- unless the two loudspeakers are identical, and identically installed, the ratio between the two impedances at each frequency will modify (distort) the frequency response of the other! 73, Jim K9YC Retired Audio Engineer ______________________________________________________________ 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 Message delivered to [hidden email] |
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