Re: [Elecraft] SP3 A/B Switch Problem (IK4EWX)
I had the same problem about one years ago. I have two SP3 loudspeakers, on on each receiver or both speakers, ore one receiver with the K3S audio effects that use both loudspeakers. The switch scratched when changing channel and it attenuated the audio signals. Keep in mind that the SP3 speaker switches only switch speaker signal. You Cannot Switch A Small-signal With A Switch. Switches need a little DC (1mA probably sufficient) to "burn clean" the contacts. I suspect that a 10K resistor from the speaker output to +12V will cause the desired 1mA to do the cleaning. Looking at the schematics, this isn't easy because R1 and R63 on the K3IO board are in the way. So, you need to add a bipolar capacitor in series, and resistors to +12V to make it happen. Don't be surprised if operating the switch will "click" a bit but 1mA is well within safe limits for the speaker. If you don't want to do through this, disconnect the K3, connect the same 10K resistor and operate the switch a few times. Elecraft isn't the only to make this design mistake - I have some Yaesu speakers that did suffer the same problem and that were remedied the same way. Since the K4 comes with a SP4 speaker that looks similar - I wonder if this design issue was addressed for the K4? 73, Geert Jan PE1HZG __ 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] SP3 A/B Switch Problem
I had the same problem about one years ago. I have two SP3 loudspeakers, on on each receiver or both speakers, ore one receiver with the K3S audio effects that use both loudspeakers. The switch scratched when changing channel and it attenuated the audio signals. The italian service obtained from Elecraft USA the switch with the connected cable and we had to change it. The real problem seemed a part failure, but we had changed it after only little more than two years of use. I would like mil parts and radio with mil parts, but a Rhode Schwartz or a Cubic cost too much... Ian IK4EWX -- Sent from: http://elecraft.365791.n2.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
[Elecraft] SP3 A/B Switch Problem
My SP3 A/B switch has an issue. I use the supplied speaker cable from my K3S to the speaker A jack. I listen with the switch in the A position, but frequently push it in to the B position as a convenient mute. Switching back to A to listen, the sound is somewhat muted scratchy; cutting in and out as I wiggled the switch. I push the switch in and out a few times, and it returns to normal. I've switched the cable to the B port, but it's the same issue. I removed the side panel, thinking I could shoot a bit of DeoxIT into the switch, but it appears that the switch is sealed, so I canned that idea. Any suggestions on an easy fix or should I order up a new switch from Elecraft and replace it? Thanks in advance Ferris Jennings NB6T - __ 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] Sp3 a/b switch
Hi, Why would the amplifier be damaged from driving an open circuit? Transformerless solid state audio amplifiers typically are perfectly happy driving an open circuit. AB2TC - Knut Don Wilhelm wrote > Richard, > > If your K3 has all the audio amplifier mods installed, there should be > no problem. If you have an early K3 without those mods, you could > damage the speaker audio amplifier by driving it into an open or shorted > load. Yes, the A/B switch will make the load to the K3 an open circuit > when switched to the non-K3 position. > -- View this message in context: http://elecraft.365791.n2.nabble.com/Sp3-a-b-switch-tp7627095p7627100.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] Sp3 a/b switch
Richard, If your K3 has all the audio amplifier mods installed, there should be no problem. If you have an early K3 without those mods, you could damage the speaker audio amplifier by driving it into an open or shorted load. Yes, the A/B switch will make the load to the K3 an open circuit when switched to the non-K3 position. See the listing of K3 mods to determine whether your K3 has the mods installed when you bought it or if they should be added. Adding the mods is not difficult and can prevent a trip to Elecraft for your K3 should the audio amp fail. 73, Don W3FPR On 2/18/2017 10:32 AM, Richard Donner wrote: Hi I was wondering if there is a problem using the A/B switch on the SP3 as a on / off switch for audio from the k3. The k3 would be on. It seems like this would be ok but I am checking with the experts here. __ 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] Sp3 a/b switch
Doing so would mean outputting the K3 into an open load I would at a minimum turn down the volume on the K3 From: Richard Donner To: "Elecraft@mailman.qth.net" Sent: Saturday, February 18, 2017 10:32 AM Subject: [Elecraft] Sp3 a/b switch Hi I was wondering if there is a problem using the A/B switch on the SP3 as a on / off switch for audio from the k3. The k3 would be on. It seems like this would be ok but I am checking with the experts here. Thanks Richard __ 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 hlyin...@yahoo.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
[Elecraft] Sp3 a/b switch
Hi I was wondering if there is a problem using the A/B switch on the SP3 as a on / off switch for audio from the k3. The k3 would be on. It seems like this would be ok but I am checking with the experts here. Thanks Richard __ 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