Low Tide Modulation Behavior Troubleshooting/Tuning Questions

Depattern

Member
I've been a fan of the Shallow Water for a long time but never tried it. So i think i know what the expected sound should be,but Im having some major issues here with mine:


1. I hear pretty much 0 modulation unless I manually modulate the amplitude of the incoming signal (outside of the pedal). So here im sending in triangle waves from the sh-101 clone, and the only time i hear modulation, is when i tweak the volume on the synth going into the pedal. when i do that, its pretty extreme, but I cant get that effect otherwise.

when i dial the BBD BIAS pot, it goes from very noisy buzzy fuzz to nothing, then an extremely short range where i almost hear a pitch warble when turning it at a certain point, but nothing obvious. like i can hear the slight pitch drift as i turn from one increment to another very small increment, but its only audible int hat specific range and ONLY when im turning the trimpot.

i can see where the behavior might be sort of intended where the pitch modulation reacts ONLY to your playing dynamics, and i guess there isnt a wide dynamic range coming from the synth notes, but you'd think i would hear a difference in depth and rate from the lfo either way

2. the MIX effected sound is only within the VERY last like 5% of the MIX knob range. I only hear effected signal at the extreme clockwise end of that knob. I dont know if this correlates with the gate tuning or what, but i've experimented with that pretty extensively I feel like

3. The DEPTH, RATE, SLEW dont seem to have any effect. I am hoping that these modulation issue can be solved if i keep working away at tweaking the BBD trimpot, but it just doesnt feel like thats going to work

4. The gate itself is not as easy to figure out whats going on. I hear when it kicks in if i set it a certain way on the trim, but its not exactly "low pass filtered"/watery to completely open, although i do hear the lo pass effect and when the BOOST switch is set, it does behave like a low pass vcf envelope, or a real lpg sort of, but its a little tricky to determine what the actual range should be. not too worried about this one, but im just not sure whether or not this is tied to the problem im experiencing with the lfo modulation

I have probably not read through every troubleshooting thread about the Low Tide here but Im working my way through them and I have read a decent amount so far, including @Jachiro's extremely helpful post about tuning the trimpots

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I believe this could be a fault in the randomizer IC. I don't think I can order them individually from PedalPCB though. Is there a recommended source for additional LM258P's?

I worked through the entire signal chain with a multimeter to isolate the fault:

1. IC6 (CD4046BE) pin 16: 5.05V - correct, chip is on the regulated 5V rail as expected
2. IC6 pin 4 (VCO output): 2.46V - clock is running
3. IC7 (V3207D) pin 3 (clock input): 1.703V - clock is arriving at the BBD
4. IC7 pin 4 (Vgg bias): 4.72V - BBD bias is correct
5. IC4 (LM258P) pin 7 (op-amp output to IC6): 1.782V fixed - does not change with RATE or DEPTH
6. IC4 pin 3 (non-inverting input, RANDOMIZER signal in): 2.36V fixed - does not change with RATE or DEPTH
 
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