This is a modified Small Clone chorus, built around Francisco's fantastic layout
at Tonepad. It sounds
beautiful, thick, lush. And it's silent when you're not playing through it. I
would recommend building this to anyone who wants an awesome 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. . .
Depth pot:
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.
Mono/Stereo switch:
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.
Stereo outputs:
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.
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