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Old 3rd September 2008, 08:18 AM   #21
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Quote:
Originally posted by panson_hk
... I would like to see the ripple waveform....
Here is my measurement of the power supply rails of an amplifier.
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Old 5th September 2008, 08:20 PM   #22
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The issue with using big and small capacitors is to use each where they make the most size, electrical, and budgetary sense.

Right after your bridge rectifier, you only need line frequency slower caps with high uF value to smooth potentially several amps of current/ripple. Closer to the chip pins you want low impedance, inductance, ESR, but at that point high uF value is not warranted.

The idea is similar to decoupling of any IC, get clean power up to the reference schematic then decouple near the chip, but in this case the chip (amp) uses orders of magnitude more power so instead of only 0.1 to 10uF decoupling caps you also want to add 100uF or more as close to the chip pins as reasonably possible.
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Old 8th September 2008, 11:41 PM   #23
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Basically being a curious mind, you should build as if you're going to have the snubbers, then not put them in yet and listen to the amp, THEN put the snubbers in and listen again.

As for whether to use big or small caps and where, it was really strange that anyone ever created controversy about this at all. The solution is to put the big caps where the large and low frequency ripple occurs, right after the bridge rectifier, and put the smaller faster caps where their properties benefit most, as close as possible to the chip pins.

Snubbers are not a make/break feature, an amp can sound fine without them but like everything else it's one of many tweaks that makes it just a little bit better, then another tweak a little better and so on. You have to decide how much to put into the amp in time and expense and go from there. Since a couple resistors and capacitors are low cost it seems one of the most reasonable tweaks to do.
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Old 9th September 2008, 01:37 AM   #24
shiraz is offline shiraz  Denmark
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Hmm...
Thanks for a nice explanation.
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Old 9th September 2008, 02:38 PM   #25
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Why snubber makes the sound different (better)? Is there any objective data? Can we see its improvement, say, ring over rails removed?

High-frequency decoupling effectiveness in analog/digital circuits are measurable. How about here?
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Old 9th September 2008, 03:11 PM   #26
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Thumbs up I agree 100%!

Well,I agree with "!" 100%, big caps after bridge rectifier...small caps on the amp board.I try many configuration and values,but at the end I chose as above.
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