low tide and caesar chorus doesn't modulate

[makisushi]

Hello there,

ince 2024, I have built around 10 pedals from PedalPCB and other brands, so I'm still fairly new to the hobby. Lowtide and Caesar were my first modulation pedals. I test my parts (resistors, caps, transistors) with a T7 tester before installing them (not the best, but decent for pedals) and a mm400 multimeter. I started by building the Lowtide, but I couldn't get any modulation out of it... Mostly noise or distortion depending on the BBD trim setting. The gate trim acts like a normal gate.. I decided to build the Caesar too to try the same BBD on both pedals. I have two sets of V3207D and V3102D chips from PedalPCB. Now, no matter which chips I put in the Lowtide or the Caesar, I get no modulation at all unless I "manually move" the knobs. I tried to measure the clock from pin 6 to 8, but I get an overload message from my DMM. So, maybe I did something wrong on both builds? or maybe I got 2 sets of bad BBD chips and clock? Any other tips to solve this issue?

Some videos of the problem:

 

[mybud]

So yeah pin 3 with ground makes the pulse led + D1 light up. Same if I short Pin 6 & 7.

Thanks for the info.

Night here, so if you don’t mind I’ll get back to you on this in the morning, ok?

 

[makisushi]

Thanks for the info.

Night here, so if you don’t mind I’ll get back to you on this in the morning, ok?

hope this build wont haunt your dreams!

 

[mybud]

hope this build wont haunt your dreams!

Ok, you’re hearing signal with the pedal engaged, the LFO’s rate is changing as you rotate the pot, the associated LED also confirms these facts, and you’re hearing chorus when you move the appropriate pot as above. Then the LFO circuit is operational. It’s just not reaching the next stage.

Have you tried playing audio through it while adjusting the trimpot?

 

[makisushi]

Ok, you’re hearing signal with the pedal engaged, the LFO’s rate is changing as you rotate the pot, the associated LED also confirms these facts, and you’re hearing chorus when you move the appropriate pot as above. Then the LFO circuit is operational. It’s just not reaching the next stage.

Have you tried playing audio through it while adjusting the trimpot?

Yes there's a sweet spot for the trim to hear a clean sound. If I go to both end of the trim I get no sound or distorted signal.

Just to summarize:
If I move some knobs manually (mostly lag) from left to right I can "simulate " a Chorus effect but there's still no pulse led (see yt video). The pulse LED light up (full on) if I short pin Pin 6 & 7 or pin 3 with ground of the tl022 (2nd yt video). I get an OL message if I try to measure HZ of the BBD (pin 6 and 8)

 

[mybud]

Yes there's a sweet spot for the trim if I go to both end of the trim I get no sound or distorted signal. Just to summarize:
If I move some knobs manually (mostly lag) form left to right I can "simulate " a Chorus effect but there's still no pulse led. The pulse LED light up if I short pin Pin 6 & 7 or 3 with ground of the tl022. I get an OL message if I try to measure HZ of the BBD

Ok, so I suggest double-checking component values around IC1, checking for cold solder joints around it, checking that your 022 is properly seated in the socket, and seeing if this gets the rate LED to flash. This seems to be the problem area AFAIK.

The BBDs’ frequency will be well into the hundreds or millions of Hz, so that’s to be expected.

 

[makisushi]

The Coolaudio V3207 BBD (Bucket Brigade Device) analog delay line has a clock frequency range of 10 kHz to 200 kHz, allowing for variable delays of 2.56 ms to 51.2 ms. I should pick up something at some range with my DMM.

 

[makisushi]

i tried replacing the tl022 with a jrc4558 still no luck. I checked for cold solders, double checked some component values... I'M just curious of why the LFO Led light up when I short pin 6 & 7 if anyone knows. I have some old MN3207 on the way also.

 

[mybud]

The Coolaudio V3207 BBD (Bucket Brigade Device) analog delay line has a clock frequency range of 10 kHz to 200 kHz, allowing for variable delays of 2.56 ms to 51.2 ms. I should pick up something at some range with my DMM.

Ok granted, but the problem seems to be with the LFO, not the BBDs

 

[mybud]

i tried replacing the tl022 with a jrc4558 still no luck. I checked for cold solders, double checked some component values... I'M just curious of why the LFO Led light up when I short pin 6 & 7 if anyone knows. I have some old MN3207 on the way also.

What happens if you take the cathode end to ground, and also are all possible grounds connected when you’re testing the circuit?

 

[makisushi]

ok so, i don't know if that's what you meant but when i wire the cathode of D1 to the ground of the PCB, the led become more bright . If i wire D2 to the PCB ground then the LFO light light up (full on) just like if I short the IC pin 6 & 7.

Please let me believe the BBD will fix it haha . I appreciate your help just spent so much time on theses two...

 

[makisushi]

some pics of the other side of the PCB

 

[mybud]

ok so, i don't know if that's what you meant but when i wire the cathode of D1 to the ground of the PCB, the led become more bright . If i wire D2 to the PCB ground then the LFO light light up (full on) just like if I short the IC pin 6 & 7.

Please let me believe the BBD will fix it haha . I appreciate your help just spent so much time on theses two...

I completely understand your frustration. It’s annoying when things don’t work as one has planned.

But FWIW do try grounding all appropriate connections to some sort of common ground. BBDs can be finicky regarding this aspect. I experienced something similar with a BBD-based circuit which only worked once I took this step, hence my advice.

Ok, I’m going to be on the road till early next week but will respond further in due course. Keep at it. We’ll get this working eventually

 

[makisushi]

Thanx I'll double check the ground in the meantime... and maybe I'll have my new old MN32007 haha! Have a nice road trip!