This Quasimodo test-jig allows to configure a snubber to avoid transformer ringing.
 
Quasimodo enables you to create an optimum snubber having critical damping (Greek letter zeta = 1.0), without requiring any calculations and without measuring the transformer's inductance or capacitance.
Use Quasimodo for using snubbers with HPULN power supplies as well as with other transformer powered power supplies.
 
Why an anti-ringing-snubber is the only solution instead of capacitors in parallel to the diodes:
Capacitors in parallel to the diodes only shifts the problems in frequency (which can make it less problematic) but mounting a snubber circuit in parallel to the transformer/rectifier input ensures the resonating energy is removed quickly and eliminates the possible RF garbage source.
Does this have any influence on the ‘sound’ off your hifi-setup? Depends on your hifi-setup and your ears… Does it reduce radiated emission ? Yes it does.
 
Important hints:
The offer contains bare PCB's only and is to be completed by oneself.
An oscilloscope is necessary to work with the Quasimodo.
Further information, the BOM (bill of material), as well as the HowTo can be found at the diyaudio-forum (first post), a (free of cost) membership at the forum is necessary to get these information.
 
The PCB's are sold with friendly permission from it's designer Mark Johnson.