---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 03/09/20: 9 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:32 AM - Re: Re: OV protection circuit design (Robert L. Nuckolls, III) 2. 06:10 AM - HEADSET POWER SUPPLY (user9253) 3. 08:44 AM - Re: HEADSET POWER SUPPLY (Robert L. Nuckolls, III) 4. 09:12 AM - Re: Re: OV protection circuit design (Jeff Luckey) 5. 09:37 AM - Re: HEADSET POWER SUPPLY (user9253) 6. 10:31 AM - Re: Re: OV protection circuit design (Art Zemon) 7. 10:41 AM - Re: HEADSET POWER SUPPLY (Charlie England) 8. 12:42 PM - Re: Re: OV protection circuit design (Robert L. Nuckolls, III) 9. 01:19 PM - Re: Re: OV protection circuit design (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:32:29 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: OV protection circuit design At 08:55 PM 3/8/2020, you wrote: >Bob, > >Those are very instructive videos. Thank you for sharing them. I >will be passing them on to some friends. Very good sir. That was a sad case to work. A very nice LA-IVP went down and people got hurt . . . some for life. It's a modern allegory to the "for want of a nail" proverb. But if there is potential for a valuable lesson learned, this is one of them. Bob . . . ________________________________ Message 2 _____________________________________ Time: 06:10:03 AM PST US Subject: AeroElectric-List: HEADSET POWER SUPPLY From: "user9253" A friend of mine wants to power his David Clark headsets from 14 VDC aircraft power instead of using the 9 volt battery box that came with the headset. He said that the electronics inside of the headset have been replaced, so the model number of the headset is irrelevant. My question is, can the headsets be powered directly by 14 VDC aircraft power, or should the voltage be dropped to 9 VDC and some filter capacitors added? Thanks, Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=495209#495209 ________________________________ Message 3 _____________________________________ Time: 08:44:16 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: HEADSET POWER SUPPLY At 08:08 AM 3/9/2020, you wrote: > >A friend of mine wants to power his David Clark headsets from 14 VDC >aircraft power instead of using the 9 volt battery box that came with the >headset. He said that the electronics inside of the headset have been >replaced, so the model number of the headset is irrelevant. > My question is, can the headsets be powered directly by 14 VDC aircraft >power, or should the voltage be dropped to 9 VDC and some filter >capacitors added? >Thanks, Joe We cannot know if the device would run reliably on 14v. The safe thing to do is duplicate the obvious and provide a quiet 9v source. It's a low-risk experiment . . . it will either be quiet enough . . . or not. Start here: Emacs! The 3-terminal regulators are powerful noise filters in themselves. Likelihood of success is high. Make sure there is a common ground between head-set plug shells and the (-) lead to the 9v battery. There is a remote chance that the audio amplifier does not share common ground with the ship's audio grounds. Bob . . . ________________________________ Message 4 _____________________________________ Time: 09:12:34 AM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: Re: OV protection circuit design Bob, At what fuse rating does the breaker pop before the fuse?=C2- 30A, 40A, 5 0A... ??? Just curious... -Jeff On Monday, March 9, 2020, 05:40:25 AM PDT, Robert L. Nuckolls, III wrote: At 08:55 PM 3/8/2020, you wrote: Bob, Those are very instructive videos. Thank you for sharing them. I will bepas sing them on to some friends. =C2- Very good sir. That was a sad case to work. =C2- A very nice LA-IVP went down and people got =C2- hurt . . . some for life. It's a modern =C2- allegory to the "for want of a nail" proverb. =C2- But if there is potential for a valuable lesson =C2- learned, this is one of them. =C2- Bob . . . ________________________________ Message 5 _____________________________________ Time: 09:37:30 AM PST US Subject: AeroElectric-List: Re: HEADSET POWER SUPPLY From: "user9253" Bob, thanks for the great advice and schematic. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=495212#495212 ________________________________ Message 6 _____________________________________ Time: 10:31:00 AM PST US From: Art Zemon Subject: Re: AeroElectric-List: Re: OV protection circuit design Jeff, Watch the two videos and you will understand that there is no answer to your question. -- Art Z. On Mon, Mar 9, 2020 at 11:27 AM Jeff Luckey wrote: > Bob, > > At what fuse rating does the breaker pop before the fuse? 30A, 40A, > 50A... ??? > > Just curious... > > -Jeff > > On Monday, March 9, 2020, 05:40:25 AM PDT, Robert L. Nuckolls, III < > nuckolls.bob@aeroelectric.com> wrote: > > > At 08:55 PM 3/8/2020, you wrote: > > Bob, > > Those are very instructive videos. Thank you for sharing them. I will be > passing them on to some friends. > > > Very good sir. That was a sad case to work. > A very nice LA-IVP went down and people got > hurt . . . some for life. It's a modern > allegory to the "for want of a nail" proverb. > > But if there is potential for a valuable lesson > learned, this is one of them. > > Bob . . . > -- https://CheerfulCurmudgeon.com/ *Sooner meet a bereaved she-bear than a fool with his nonsense. *Proverbs 17:12 ________________________________ Message 7 _____________________________________ Time: 10:41:52 AM PST US Subject: Re: AeroElectric-List: HEADSET POWER SUPPLY From: Charlie England On 3/9/2020 10:40 AM, Robert L. Nuckolls, III wrote: > At 08:08 AM 3/9/2020, you wrote: >> >> A friend of mine wants to power his David Clark headsets from 14 VDC >> aircraft power instead of using the 9 volt battery box that came with >> the >> headset. He said that the electronics inside of the headset have been >> replaced, so the model number of the headset is irrelevant. >> My question is, can the headsets be powered directly by 14 VDC aircraft >> power, or should the voltage be dropped to 9 VDC and some filter >> capacitors added? >> Thanks, Joe > > We cannot know if the device would run reliably > on 14v. The safe thing to do is duplicate the > obvious and provide a quiet 9v source. It's > a low-risk experiment . . . it will either > be quiet enough . . . or not. Start here: > > Emacs! > > The 3-terminal regulators are powerful noise > filters in themselves. Likelihood of success > is high. > > Make sure there is a common ground between > head-set plug shells and the (-) lead to > the 9v battery. There is a remote chance > that the audio amplifier does not share > common ground with the ship's audio grounds. > > > Bob . . . > FWIW, I've had excellent luck using LM78xx fixed voltage regulators with no external components, as voltage dropping regulators in both cars and airplanes. LM7809 would give 9V output. Wired similar to the 317, with in/GND/out. I just used an LM7805 to power a serial output GPS puck (5V power supply required), used as position source for a GRT HX EFIS. No external components, no risk of drift, etc. In extremely low current applications like mine, I could get away with no heat sink. Might be different with the Bose; I have no idea on its power consumption. Charlie -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 8 _____________________________________ Time: 12:42:46 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: OV protection circuit design At 11:10 AM 3/9/2020, you wrote: >Bob, > >At what fuse rating does the breaker pop before the fuse? 30A, 40A, >50A... ??? > >Just curious... No hard and fast rule . . . both breakers and fuses can be had in a range of trip profiles. I've tested the ATO/ATC30 plastic fuses against the miniature breakers popular in aircraft with a goal of at least 3x head-room with a 100A crowbar event. I couldn't find my favorite 300A HE sensor but did find a 400A that will let me repeat the bench tests but I'll take a look at the ATO40 fuse also. Bob . . . ________________________________ Message 9 _____________________________________ Time: 01:19:15 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: OV protection circuit design At 11:10 AM 3/9/2020, you wrote: >Bob, > >At what fuse rating does the breaker pop before the fuse? 30A, 40A, >50A... ??? > >Just curious... No hard and fast rule . . . both breakers and fuses can be had in a range of trip profiles. I've tested the ATO/ATC30 plastic fuses against the miniature breakers popular in aircraft with a goal of at least 3x head-room with a 100A crowbar event. I couldn't find my favorite 300A HE sensor but did find a 400A that will let me repeat the bench tests but I'll take a look at the ATO40 fuse also. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.