Duo-Phase LFOs not working

eduardcastillo

New member
I'm stugling with this duo-phase build. Everything in the pedal seems to work fine exept the LFOs on both sides. I've used a flashlight to triger the ldrs and it sounds like a phaser. I've tried resoldering some con ectionsd that seemd off to no avail. I'm able to take measurements of the ICs however, I'm not sure where to put my negative probe of the dmm. Any help is apreciated. I've atatched some pictures of the board
 

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Mcknib

Well-known member
Some of your 4K7s look like 47K and visa versa R36B 4K7 should be 47K, R8, 11, 12B look like 47K should be 4K7

Visually check all your resistor colour band values are correct it's easy enough to mix them up

I'm at work on my phone so hard to check everything with the mahoosive schematic etc

Think I answered you on reddit too
 

mybud

Active member
I think the way to use a DMM is to connect the negative probe to ground as a reference and use the positive one to measure DC (or AC) voltages. I’m going to do the same, since my build is showing the same symptoms as yours. The LEDs light up and change brightness with the depth control in each case but there’s no oscillation (variation in either LED) from either rate control. Before I send pics through, I’m going to double-check all resistors and caps are correct. It’s quite a weird problem and disappointing for my first build of the new year. But it happens as we know.
 

ADAOCE

Well-known member
Check those two pots aren’t touching the backside of the board. You should really use dust caps or something to protect them from shorting
 

mybud

Active member
Ok, so I tried the flashlight and heard phasing, same as Eduard. But I’ll supply pics after double-checking values etc in the morning. Best to all.
 

mybud

Active member
@eduardcastillo: I experienced exactly the same problems as you. It helps to do the testing with the lights off, I was advised. Otherwise the ambient light in the room stops the LEDs from operating correctly. This makes sense since (at least with my build) it seems the LEDs work best when they are almost off. Thanks to JimiLee‘s advice, I’ve managed to get the circuit working. Hope this helps.

Best, mybud
 
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