Interesting story of Blue LEDs

[Zen Mod]

How else are you going to stand out from the crowd?

car cigar lighter as indicator?

 

[Preamp]

Runs hot, not very energy efficient... seems adequate for Class A equipment 😉

 

[Ixnay]

hmmm, maybe a piece of card stock with cutouts, and another slip of card stock behind it with a red stripe, that is moved from cutout to cutout by means of the selector switch. Wait till I get to the patent office with this one!

 

[ARGOS]

One of the post docs who was in the same group I was in had done some early work of SiC leds. This would have been late 70’s. At the time they only worked at liquid nitr temperature.

 

[Zen Mod]

seems adequate

I have diesel engine glow-plug as peak-indicator, in my preamps

 

[wrenchone]

GE also came up with a led that used a conversion phosphor that stored ambient light and released yellow light when hit by IR. I still have the sample in my junk box somewhere - it wasn't astoundingly brilliant.

 

[rayma]

hmmm, maybe a piece of card stock with cutouts, and another slip of card stock behind it with a red stripe, that is moved from cutout to cutout by means of the selector switch. Wait till I get to the patent office with this one!

Indicator flags were used a lot in push button switches before LEDs, like in 60s gear.
Hafler also used some in their DH-101 preamp.
https://www.hifiengine.com/manual_library/hafler/dh-101.shtml

 

[adason]

These are my kind of blue leds 🙂

 

[Demonkleaner]

Maybe some 866A's with UV blocking lenses?

 

[Ixnay]

Yah, I know, I still have seizures from my Marantz 1060 that I owned in the early 70's. Color blind in one eye. black and white in the other.