Comments on: XLR Mic cable tester with one LED https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/ All about electronics and circuit design Wed, 22 Apr 2026 08:40:06 +0000 hourly 1 http://wordpress.org/?v=3.9.14 By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1794439 Thu, 02 Feb 2023 21:06:12 +0000 https://www.epanorama.net/blog/?p=189194#comment-1794439 LEDs on phantom power
https://repforums.prosoundweb.com/index.php?topic=36697.0

Mic MUTE with Led/Phantom Power
https://www.diystompboxes.com/smfforum/index.php?topic=119381.0

Power LED from 48 volt phantom power
https://www.diyaudio.com/community/threads/power-led-from-48-volt-phantom-power.194283/

Adding a phantom “on” LED
https://gearspace.com/board/geekzone/932364-adding-phantom-quot-quot-led.html

Tapping phantom power for LED
https://gearspace.com/board/geekzone/929969-tapping-phantom-power-led.html

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1765438 Wed, 20 Apr 2022 11:39:58 +0000 https://www.epanorama.net/blog/?p=189194#comment-1765438 Cable Matters XLR | Quick look at Popular Budget Mic Cables
https://www.youtube.com/watch?v=uO5JqHQSiFw

Budget XLR cables can seem like a great deal compared to pricey professional options, but what’s the difference? Let’s crack open a Cable Matters XLR and talk about how it compares to other budget cables, and also to the Genuine Neutrik connectors they’ve copied.

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1750712 Mon, 10 Jan 2022 18:18:11 +0000 https://www.epanorama.net/blog/?p=189194#comment-1750712 Interesting finding:

The tester LED lights up also when the circuit is connected to DMX-512 light control desk signal output.

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1726984 Wed, 06 Oct 2021 21:12:57 +0000 https://www.epanorama.net/blog/?p=189194#comment-1726984 LT Spice – PC817 Optocoupler Simulation
https://m.youtube.com/watch?v=isI8fNZyY3g&feature=youtu.be

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1724459 Wed, 15 Sep 2021 21:59:32 +0000 https://www.epanorama.net/blog/?p=189194#comment-1724459 https://fi.farnell.com/on-semiconductor/1n4148tr/diode-100v-200ma-do-35/dp/9843680?gclid=EAIaIQobChMI0efg2JfZ8gIVSRV7Ch22sgAREAAYASAAEgLOIfD_BwE&mckv=sf5ymcojh_dc|pcrid|63102874234|kword|1n4148|match|p|plid||slid||product||pgrid|14106935314|ptaid|kwd-561786311|&CMP=KNC-GFI-GEN-SKU-MDC

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1723343 Sat, 04 Sep 2021 07:13:41 +0000 https://www.epanorama.net/blog/?p=189194#comment-1723343 Commercial testers
https://www.ltt-versand.de/en/sound/audio-tools-accessories/cable-testers/21957/xlr-function-tester-48v
https://www.ratsoundsales.com/mm5/merchant.mvc?Screen=PROD&Product_Code=soundtools-xlr-snifsend

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1723293 Fri, 03 Sep 2021 14:19:04 +0000 https://www.epanorama.net/blog/?p=189194#comment-1723293 https://www.circuitbread.com/ee-faq/the-forward-voltages-of-different-leds

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2021/08/29/mic-cable-tester-with-one-led/comment-page-1/#comment-1723292 Fri, 03 Sep 2021 14:17:35 +0000 https://www.epanorama.net/blog/?p=189194#comment-1723292 Wouldn’t a pin 2-3 short produce the same results as no fault in this circuit?

No it won’t give no fault result. There is some magic on voltage drop difference between the optocoupler LED side (around 1V) and red LED (1.8-2V). When pin 2 and 3 are shorted, the optocoupler LED side and red LED side are effectively in parallel, optocoupler takes all current atv1V voltage drop and does not leave enough voltage to let red LED turn on.

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