Will these LEDs give my tone more Mojo (TM)

[tootsMcgee]

I found these in the bottom of my electronics box...iirc they were in a collection of parts I inherited from a family friend. Might as well use them? They're not doing anybody any good sitting there. I need the four LEDs for my Andromeda Deluxe build: https://aionfx.com/project/andromeda-deluxe-natural-overdrive/



More interesting question: those mini (neon?) bulbs. Is there anything interesting I can do with them in the signal path? I have a couple of packages of them.

Very interesting to see the pricing of that era: LEDs were more expensive than the mini bulbs!

[ElectricDruid]

Very interesting to see the pricing of that era: LEDs were more expensive than the mini bulbs!

Especially the green ones! They were the latest, greatest thing. The early green LEDs were pretty yellow is what I remember, and only later did they become properly green. And they stayed a lot more expensive than "ordinary" red LEDs for a long while.

[PRR]

those mini (neon?) bulbs

6V 60mA is VERY clearly in the incandescent range. And probably aimed at little stoplights for model railroads.

There's a phaser uses little incandescents like that to light photoresistors. You could modernize with LEDs but there is some mojo in slow incandescents.

[tootsMcgee]

those mini (neon?) bulbs

6V 60mA is VERY clearly in the incandescent range. And probably aimed at little stoplights for model railroads.

There's a phaser uses little incandescents like that to light photoresistors. You could modernize with LEDs but there is some mojo in slow incandescents.

Interesting idea! It makes me think of Univibe style pedals too. I don't have one of those yet. Hmmm. Will consider.

That makes me think of something else: these early green LEDs, any chance they have an unexpected Vf?

On the back it says 2.1V forward voltage at 10mA. That seems right on the money ish for https://electronics.stackexchange.com/questions/390237/3mm-different-color-led-resistances-for-bright-light and significantly more than red LEDs at around 1.5V at the same current. I guess that answers my question.

For this particular circuit I think that these LEDs are blended into the feedback network via an "Overdrive De-Compress" control: https://aionfx.com/app/files/docs/andromeda_deluxe_documentation.pdf

This makes me think that at its maximum, the green LEDs would yield the most gain but the red ones would still work fine. Maybe I should socket these and experiment...

[merlinb]

It's difficult to find a use for incandescent lamps these days. In theory you could use them in any LDR-based effect like tremolo, phaser, compressor... but you pay a high price in current for (probably) minimal tone reward! I guess you could think of a whacky compress-ish OD effect where the bulb is in series with the power supply, so it acts kinda like the sag you get from a tube rectifier, maybe supplying an LM386? I'm just spitballing.

[Mark Hammer]

This makes me think that at its maximum, the green LEDs would yield the most gain but the red ones would still work fine. Maybe I should socket these and experiment...

There's a reason why one generally sees RED LEDs used for clipping, and not any other colour.  And that reason is that they have the lowest Vf of any of the LED categories, making them simply more practical.

[amptramp]

In one circuit where I used red LED's, the voltage drop was 1.88 volts whereas in another circuit where I used green LED's, the voltage drop was 2.05 volts.  I expected more of a difference but this was the reality.

[MikeA]

IR LEDs measure as low as 1.1V @ 4 mA.