This Week on the Breadboard: Shallow Water

Should not be noisy. There could be many causes and this is not a troubleshooting thread. ;)

In other news, I tried adding feedback around the BBD like we would find in a flanger. Very interesting. It magnifies the vibrato effect and with a lot of feedback, we get that "talking thru a vacuum cleaner hose" tone. Right now I have the feedback is controlled by a knob, butt-eye think a 3-way toggle switch will do: No Feedback, Moderate Feedback, Heavy Feedback.
 
Chuck D. Bones said:
I don't get why Fairfield adds gain in the first stage and then takes it all away in the BBD's input filter. I also don't understand why Fairfield runs the V3207D & CD4046 on 5V when they work as well or better on 9V. Definitely more headroom in the BBD at 9V. The input and output preamps work perfectly well, but could have been implemented by a dual opamp. There is a significant volume shift when turning the MIX knob from Dry to Wet. Not sure why Fairfield did that.
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Cool work, just on this note - it would be easy enough to ask him and find out. Guillaume is a mellow guy, he's shared schematics and is pretty open about their stuff.
 
I’m slowly putting the schematic together to build a board. Should I go 1590BB size or try to go stacked 125B? Personally, I’m aiming for stacked 125B, but I’ve never done that before. Thoughts?
 
pbrommer said:
I’m slowly putting the schematic together to build a board. Should I go 1590BB size or try to go stacked 125B? Personally, I’m aiming for stacked 125B, but I’ve never done that before. Thoughts?
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I built this soon after Robert made it available and I plan to explore the Boneyard tweaks. The larger build will give you more room to play around with mods, but if real estate on your board is at a premium, the stacked build would be a better choice.
 
Chuck D. Bones said:
I also don't understand why Fairfield runs the V3207D & CD4046 on 5V when they work as well or better on 9V.
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Probably because these parts along with the TINY comprise a digital section on a separate digital supply for noise decoupling. The TINY was the bottleneck for the rail. I'm curious about your other questions, but can't really answer without seeing a schematic of the original circuit. No schematic in the build document. Where are builders getting their randomizer code from?
 
Chuck D. Bones said:
The V3207D is a "mixed mode" part in my mind. The delay line is pure analog. The clocking could be considered digital. The CD4046 is also part analog, part digital.

https://docs.pedalpcb.com/project/LowTide-Schematic-PedalPCB.pdf

If you buy the Low Tide board, a randomizer chip is included. It is similar to the randomizer in the Shallow Water.
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The outputs of BBDs are mosfet source followers that are out of phase and only 'on' with different half cycles of the clock. So the outputs look like high frequency pulses that correlate with the clock. It's only after summing and the reconstruction filter that they start to resemble an analog signal again. The BBD also generates noise that correlates with the digital clock. It is good to think of it as a digital device, at least for purposes of decoupling I think.

And yeah, I purchased a kit a few days ago, and also managed to find the schematic. I wasn't sure if the randomizer IC was included.
 
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