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In Reply to: RE: Peak current posted by Paul Joppa on June 29, 2015 at 20:28:25
"Nobody has any idea what that minimum time constant is for an RC filter to produce the same audible result as a regulator."
It's not possible to answer this with a single number. The necessary minimum time constant varies as a function of the load on the supply. The lower the load Z becomes in terms of its AC component, the shorter the time constant of the supply must be.
Personally, I think the sonic effectiveness of supply voltage can be easily observed and measured. If the amplifier at full output can't wiggle the supply to any significant extent, that aspect of the system is good.
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Follow Ups:
"If the amplifier at full output can't wiggle the supply to any significant extent" - over what time scale? The biggest likely effect will be envelope modulation because the loud passages demand a bit more average current than the quiet passages. So, does the supply need a time constant equal to Beethoven's 9th? Will a minute do? A second?
It's at least a 2-dimensional problem - the depth of the effect (power supply ESR relative to load ESR) plus the speed or slowness with which the wiggling takes place. Jeff has (somewhat forcefully) advocated for a low power supply ESR; I am interested in the time dimension. A regulator addresses both.
" over what time scale? The biggest likely effect will be envelope modulation because the loud passages demand a bit more average current than the quiet passages. "
In order to have a meaningful discussion about this, we would first have to agree on the difference between A) power supply sag that occurs at less than 1Hz, and B) power supply output Z over the musical frequencies. I can only say at this point that I don't equate long-time-constant power supply sag with envelope modulation.
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Buy Chinese. Bury freedom.
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