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a modified Small Clone chorus, built around Francisco's
layout at Tonepad. It sounds
beautiful, thick, lush. And it's silent when you're not
it. I would recommend building this to anyone who wants an
sounding chorus pedal.
There are six different mods that I added, some of which are described in build notes others have posted at Tonepad, some were from discussion threads at Aron's DIY Stompbox Forum, and I worked out a couple, like the blinking LED, myself. For the graphics, I used the same method as I did on the Squelchy Squarefuzz (I'm still a little heavy-handed with the iron, tho). As for the name, well. . . after I got done with the mods, it just seemed to fit. Here's what I did. . .
I replaced the Depth switch with a 100K pot. Details are in the build notes for the Small Clone at Tonepad.
Depth adj. switch:
This is the 4-position rotary switch in the center. I replaced the 150pF cap that's on the CD4047 with two leads going to the switch. Now there are four different cap values that can be switched between. I used 33pF (mellow chorus), 100pF, 180pF, and 330pF (pitch bending wierdness). This allows for a huge range of sounds. My only complaint about this one is that there is a very audible "pop" when switching between settings. I edited the "pops" out of the audio clips, above.
Speed adj. switch:
This is the SPDT toggle switch above the speed pot for switching the capacitor that's on the LM358. I kept the 2.2uF and added a 1uF, which will make the LFO go much faster.
This is like a chorus/vibrato switch. It's the SPST toggle switch above the depth pot. On the PCB, I cut the trace between the 22K resistor and the junction of the 10K/20K resistors, in the area just above the 4558, and brought a lead from each side of the cut to the switch. Using only Output A, in mono mode the switch makes the connection and the sound is stock. In stereo mode, the switch breaks the connection, eliminating the clean signal, leaving only the modulated/delayed signal. Depending on how the Depth adj. switch is set, this gives a range of effects from vibrato to pitch bending. See build notes at Tonepad for a little more on this mod.
The mono/stereo switch needs to be in the stereo position to get a stereo output when using both of the outputs. Output B has the straight, unmodulated signal. Output A has the modulated signal.
LED pulses at LFO rate:
Instead of powering the status LED from the +9V power rail, I connected it to pin 1 of the LM358, thru a 47ohm resistor. I didn't have to drill into the board an add a new wire for this. I just tapped off of the speed adj. switch.