Check the listing for details. Custom Quasimodo V4 Transformer ringing Snubber Test Board for tuning Values. Condition: Brand New. Listed at 15.87 USD. This is my Version of the Quasimodo V4 Board.I've made easy connection and test point locations. I will have Custom Filter Boards to use with this filter that fit over standard size rectifiers.I will post these up in its own listing.This Board is also used to determine the AC input filter for the BA3 PSUs. Simple, no-math transformer snubber using Quasimodo test-jig A power transformer snubber is a wonderful thing for reducing or eliminating RFI from rectifier-induced LCR ringing. Unfortunately it's a huge pain to design and optimize a snubber. First you have to measure the transformer's leakage inductance and secondary capacitance, at about 100 kHz, which is not especially easy. Then you have to estimate the capacitance of your rectifier(s), which does not always appear on datasheets. Finally you plug these numbers into a formula that spits out snubber values -- and then you hope it's all correct. This here is a little test jig called "Quasimodo the bell-ringer" which makes this process a great deal simpler. Quasimodo connects an actual snubber across the transformer, smacks the transformer to make it ring, and you observe the ringing on an oscilloscope. Then you adjust a (25 turn) potentiometer on the jig, watching the scope to find the setting which completely damps out all ringing. And you're done! Just use the same snubber values in the end product, as you used on the test-jig, and success is yours. (The 25 turn trimpot is socketed for ease of measuring the final resistance that gave perfect damping).