EAZIUS TREMOR Optical Tremolo

[ForcedFire]

This is the audio path of the Tremulus Lune with the LFO from the EA tremolo. The LFO is the modded version from GGG with the LED like the BYOC version and a couple of mods I made.

I used the Burr Brown OPA 2134 and it sounds fantastic.

The depth controls the brightness of the LED but not the ratio of bright to dark so it isn't really a depth, it's more like an external volume knob. I really like the sound of the OPA 2134 when it gets a bit gritty. I like fast overdriven tremolo for that rockabilly vibe. To get this I set the trim pot pretty high, even cranked to 50k and use the Depth knob to control how loud or gritty the sound gets.

I used a 5mm Yellow Diffused LED with a photocell that has a light resistance around 2k and dark resistance around a couple of mega ohms. This makes it a bit more of a pulse and sort of sounds like a rotating speaker effect to me. The info above should get you started but you can make your own version with different LED/LDR/photocell combinations. To make a more traditional depth knob, look at the tremulus lune how the pot varies the signal to the LED between the LFO signal and 9V.

I do not have the part number for the photocell.

Youtube clip: http://www.youtube.com/watch?v=Mns4TQdDzZk

[Cliff Schecht]

That schematic is a little EXTREEMMEE!!! for my tastes..

[petemoore]

  I like it !
  Thanks for Posting !
  I was considering rebuilding the Lune, but to a much simpler degree of adjustability [1 or 2 'good trem-tones suits me just fine...one for 'Midnight Special' and one for 'Too much to dream'.

[kristoffereide]

I'm having problems with getting sound from this...
The indicator LED seems weak and the trem-LED isn't strong either.
No sound at all from it. What do you think is wrong?
Do I have to use that exact IC?

[ForcedFire]

What power supply are you using? What indicator LED? The IC doesn't matter, you can use any dual op-amp.

[kristoffereide]

Im using a 9V 1700mA adaptor, which i believe is more than enough. The LED is 5,1V 20mA. Does the LED matter really? I didn't know that.

[ForcedFire]

Yeah, 5V is too high. Use a normal LED, 1.5V or something. The LED is part of the oscillator so a 5V drop is probably going to mess up the biasing.

[kristoffereide]

ok, I'll give it a go. Thanks!