Simple, no-math transformer snubber using Quasimodo test-jig

@Dewdrop,
My lack of sophistication in electronics leads me to use X2/Y2 rated safety capacitors in snubbers where I can, since to me they appear to be "across the line", although generally at low voltage where I use them. I think (?) member Jeff Young gently suggested this previously as well (I unabashedly stand on the shoulders of those wiser/smarter than me.)

Is an X2 rating inappropriate or too conservative? Perhaps, but in the case of an over-voltage/over-current event, I have some assurance that they will fail predictably and not start a fire because of their construction.

A disadvantage is that because of their construction, it's hard to find case sizes smaller than pcm 7.5 or 10 for the capacitance values suggested by Quasimodo. And they may be a bit more expensive than non-safety caps.

I have been using Kemet R46 and Rifa PHE840 without event.
 
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@Dewdrop,
My lack of sophistication in electronics leads me to use X2/Y2 rated safety capacitors in snubbers where I can, since to me they appear to be "across the line", although generally at low voltage where I use them. I think (?) member Jeff Young gently suggested this previously as well (I unabashedly stand on the shoulders of those wiser/smarter than me.)

Is an X2 rating inappropriate or too conservative? Perhaps, but in the case of an over-voltage/over-current event, I have some assurance that they will fail predictably and not start a fire because of their construction.

A disadvantage is that because of their construction, it's hard to find case sizes smaller than pcm 7.5 or 10 for the capacitance values suggested by Quasimodo. And they may be a bit more expensive than non-safety caps.

I have been using Kemet R46 and Rifa PHE840 without event.



Thanks Johnny!
 
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Joined 2011
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Occasionally I've thought about replacing Cx in a transformer secondary snubber, with a Metal Oxide Varistor. MOVs are overvoltage protection devices, similar to big gigantic bidirectional zener diodes. Because of their large size, big MOVs have lots of capacitance between their terminals. Some datasheets say it's tens of nanofarads. Bingo, right in Cx territory.

Unfortunately, the capacitance of a MOV is nonlinear. It varies with voltage. This makes Quasimodo-style testing a bit more involved, since now you must apply the correct bias voltage to "Cx" while performing the bell-ringing experiments. It's probably possible but undoubtedly messy.

It might be true that using a surge protector outlet strip, between the audio equipment and the AC mains, is easier.
 
Quasimodo is ready for ringing ;). Now I just need to get an oscilloscope. Thanks Hicoco for the PCB :) IMG_0002.jpg
 
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Hi Orelli,

My experience with the audible effects of adding these snubbers is based on both first impressions as well as long-term listening. The music sounds more natural and "real" with instruments and voices being better defined and separated from other parts of the music. There seems to be a loss of "grainyness" to the sound that results in a quieter background and better dynamics. Overall everything just sounds more realistic and more pleasant to listen to. These changes have been consistent for me regardless of whether the snubbers were installed in preamps, power amps, or even the HV bias power supplies in my electrostatic speakers.

Quoted from member jameshiilj on post #604: "I myself find the effect is a lot 'smoother' sound with less fatigue plus added 'punch' and depth to the sound"

Post #823 describes another member's experiences and Mark himself talks about some differences in post #241.

Perhaps other Quasimodo users could chime in here and add their own observations.

Take care,
Doug