GeneralTSO Question - Green LED

jdduffield

jdduffield

Active member
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.
 
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.
 
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.
 
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.
 
z2amiller said:
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.
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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.
 
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