GeneralTSO Question - Green LED

[jdduffield]

For the optical part of the GeneralTSO, it says to use a 5mm Green LED. Does it matter if the LED is clear when it is off?

I have both the green tinted ones and the clear bright ones. The tinted ones are diffused and the clear ones are not diffused. Both are green when lit.

 

[jdduffield]

Examples:

 

[z2amiller]

I have no direct experience w/ the Tso, but a couple of things I know:
- The 'waterclear' versions of LEDs often have a higher Vf than the diffused versions. I think this circuit is built with the Vf of the diffused green LEDs in mind so might not work as well with a different Vf. (You can measure with a multimeter on diode test mode to see the Vf)
- The waterclear LEDs are often brighter as well, which may or may not throw off the response curve.
- From previous reading of the forums about this pedal, the consensus seems to be that you want the LED a little distance away from the LDR so that the light shines more evenly on the LDR. I assume that the diffusion is helping in this case.

 

[falco_femoralis]

It doesn't matter whether it's clear when the LED is off, but when its on the diffused versions of LEDs have a lower forward voltage and are the "default" version when compared to the waterclear superbright version. I would presume that the circuit is designed with the Vf of the diffused version, if it matters.

 

[jdduffield]

Ok, thank you.

 

[RobinMallard]

It’s not really what you asked, but I recently swapped out the LED/LDR combo in mine for VTL54C’s and I like the result a lot more - compression seems more noticeable, but still pretty subtle.

This change has been described by a few others here, and might be worth considering.

 

[eskbedstraw]

I have no direct experience w/ the Tso, but a couple of things I know:
- The 'waterclear' versions of LEDs often have a higher Vf than the diffused versions. I think this circuit is built with the Vf of the diffused green LEDs in mind so might not work as well with a different Vf. (You can measure with a multimeter on diode test mode to see the Vf)
- The waterclear LEDs are often brighter as well, which may or may not throw off the response curve.
- From previous reading of the forums about this pedal, the consensus seems to be that you want the LED a little distance away from the LDR so that the light shines more evenly on the LDR. I assume that the diffusion is helping in this escape road case.

Yeah that all makes sense to me

I’ve run into similar stuff with LEDs and LDRs before—those waterclear ones can be kind of “too good” in a way because the light is so focused. You end up with hotspots instead of nice even coverage, which probably messes with the response.