The guys at Earthquaker made some improvements to the original circuit. Smaller, more reliable by using leds instead of light bulbs. Able to run it at 9v-18v and adding some extra controls. So there was not much left for us to do but giving you an extra tonal option. Via toggle switch and bi Color led you can get even more sounds out of it, then the original provides. I highly recommend using sockets to experiment with the leds and solder the LDR’s in after you got an idea how tall the led in the sockets will be. So you can match the height. While the original EQD unit uses a yellow led you could use a green/yellow led. With minor difference in sound or a red/blue the difference there is way more present without a need to touch any knob but it’s overall a bit sharper sounding. Personally I used a single Color orange diffused led for a tone that made me more then happy. In case you‘re so in love with one specific led you can leave the toggle out and solder a jumper. I highly recommend experimenting with this and the distance between LDR and led. To get equal distance between them you can simply use a guitar thick 2mm guitar pick as spacer.
- Intensity: This controls how subtle or intense the overall effect is. Counterclockwise from noon are the more subtle, classic sounds. Clockwise from noon are the more drastic and intense sounds.
- Voice: Dials in the overall sound. Turn it clockwise for a fuller sound with more lows, bring it back for a thinner, more midrange focused tone.
- Rate: Controls the speed of the effect. Counterclockwise for slow, clockwise for fast.
- Level: Controls the volume of the effect. Unity is around 1 o’clock, everything above that is boost.
- Throb: This controls the low end pulse. It may not be immediately evident on the bridge pickup, but switch to the neck or add some dirt and it comes alive. All the way up for more throb, dial it back for less. Works best when the Voice is set to a warmer tone.
- LED toggle: Allows you to choose which color of the bicolored LED will shine, changing the behavior of the effect.