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Jake T <jaketbone@steak.com>: Jan 11 08:13AM -0500 Quick question for what I hope might be a simple circuit. I just set up an ultra sensitive electret mic to monitor some bird activity near my residence. There was no AGC used, so when a jet flys close, it sounds like my speakers are going to burn out from the loud sounds. Of course, i suppose I could build an AGC, but was looking for something simpler, maybe something that would mute the audio when a certain audio level is exceeded? Suggestions for such a circuit would be welcome. It would be placed between the mic output and speaker. Thanks in advance.

"Peter W." <peterwieck33@gmail.com>: Jan 11 06:30AM -0800 https://sound-au.com/articles/muting.html   Is a start. Battery power adds complication.   Peter Wieck Melrose Park, PA

Jeff Liebermann <jeffl@cruzio.com>: Jan 09 11:25PM -0800 On Mon, 10 Jan 2022 05:27:26 -0000 (UTC), danny burstein >>(state of charge).   >Thanks. That article (which, despite coming through Elseveir, >is a freebie) is *exactly* the background info I was looking for.   OSTI (US governmint office of scientific and techy info) apparently contracted with Elseveir to handle their distribution. I forgot to mumble something about the article search: <https://www.osti.gov> They have 23,135 articles listed under "lithium ion battery safety" keyword search: <https://www.osti.gov/search/semantic:lithium%20ion%20battery%20safety> or 147 under the exact phrase: <https://www.osti.gov/search/semantic:%22lithium%20ion%20battery%20safety%22> The first article found is rather interesting: "Materials for lithium-ion battery safety" <https://www.osti.gov/servlets/purl/1475493> This Review aims to summarize the fundamentals of the origins of LIB safety issues and highlight recent key progress in materials design to improve LIB safety.   >So they seem to agree with me. In a residential setting with >a couple of e-bike batteries, the fire risk is almost entirely >from "thermal runaway" and not gas production/escape.   In my never humble opinion, the more likely eBike scenario is mechanical damage, either from modifying or soldering the battery pack cells, or having the eBike crash into something. Also included are high resistance contacts causing the safety fuse to fail to trip, BMS (battery management system) misprogramming or miswiring, and various attempts to convince the eBike to deliver more power. Locally, I've only seen 3 eBike fires and have been told about 3 others. All were the result of owner tampering, shoddy repair, cell replacement, or combinations of these. A commercial eBike system is probably fairly safe. A do-it-thyself mess of mods and repairs is probably not so safe.   Hint: Store your batteries in a fireproof box, preferably with a working smoke alarm nearby: "Underrated E-Bike Battery Fire Hazards Call for Attention on Safe Storage" <https://www.bike-eu.com/home/nieuws/2018/02/underrated-e-bike-battery-fire-hazards-call-for-attention-on-safe-storage-10132804> Methinks things will be better when the cobalt cathode are replace with LiFePO4 cells.   -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558

Bob Engelhardt <BobEngelhardt@comcast.net>: Jan 11 08:45AM -0500 On 1/8/2022 11:55 AM, Dave Platt wrote:   > And, if you download the Digi-Key paper order form, fill it out by > hand, and mail it to Digi-Key with a check for the full cost of the > component, they'll pay the shipping charge. ...   That seems like bad business: processing a paper order is going to be much more expensive than an automated online order. And it encourages itsy-bitsy orders which are certainly money losers. I suppose that it's basically a customer-relations thing & not for-profit.   I like DigiKey and try not to abuse their no-minimum with trivial orders. And when I do, I'm happy to pay for shipping.

Chuck <chuck23@dejanews.net>: Jan 10 11:43AM -0600 On Mon, 10 Jan 2022 07:34:59 -0800 (PST), "Peter W."   >Service Manual here: https://www.hifiengine.com/manual_library/yamaha/cdc-e250.shtml   >Peter Wieck >Melrose Park, PA Thanks Peter. I had already downloaded it. I was hoping there was a known flaw and fix that could speed up the repair since this is a freebie.

"Peter W." <peterwieck33@gmail.com>: Jan 10 11:01AM -0800 On Monday, January 10, 2022 at 12:43:27 PM UTC-5, Chuck wrote: > I was hoping there was a > known flaw and fix that could speed up the repair since this is a > freebie.   In a word: Yamaha.   Peter Wieck Melrose Park, PA

Adrian Caspersz <email@here.invalid>: Jan 11 06:33AM On 10/01/2022 19:01, Peter W. wrote: >> known flaw and fix that could speed up the repair since this is a >> freebie.   > In a word: Yamaha.   <ouch>   One project I have had on the theoretical bench a long time, is to replace some of the read electronics in a CD changer with some from a CD ROM drive.   Then I could pile my CDs into it, and have them rip'ed without having to constantly attend to the thing....           .... however, music streaming became a thing, and Spotify has already got my library online ...     -- Adrian C

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