Don't know if this has come up yet, but I'd just like to contribute something I discovered:
After building the echo base, I was thrilled, but over time it started acting funny. I'd get self-oscillation when playing with the Depth and Delay knobs with Feedback turned way down, and there was this horrible ticking coming from the LFO whenever I switched modulation on. Not too noticeable until you use a booster or something after the EB.
Well my brother's puppy decided to pee on my Uglyface and V847 last week, so I took my whole chain apart to clean up, unplugging my Echo Base for the first time since I built it (yes, it's that good, thank you

)
All noise issues gone! I'm guessing sending it into oscillation over and over and over without powering off was the cause of this... Resetting was a quick fix for me. Could anybody else with ticking issues confirm?