The large bypasses came about through a lot of experimentation over the years. I found that .1 microfarad film bypasses seemed to help sweeten the very high audio frequencies but not much anywhere else. Doubling & tripling that resulted upper midrange glare which I reasoned was due to an increase in output in that area without the necessary body support from the frequencies below so I started trying larger & larger caps until I could get the necessary body & hence get a consistent sound signature through out the frequency range. It is for the reason of glare I believe most all manufacturers & modifiers shy away from the slightly larger caps & really never try to go beyond those early attempts as it does sound worse than either staying small or going whole hog like I did. About 5uf is enough to get a consistent sound signature but I reasoned that larger ones would give me improved dynamics & so it has. Having a consistent sound signature is as important as improving apparent resolution which these mods do as well especially noticeable in the greater clarity of background instruments & voices. All this without glare because the body is there These sizes work great for small signal amps & DAC's but even larger ones are necessary to get these improvements out of power amps.
They work because the power supply is in the direct signal path & the benefits are identical to using film caps exclusively for coupling between stages & different components though I actually prefer to direct couple so there is no unneeded caps in the signal path. Even my power amps are full direct coupled even to ground from the negative feedback loop making the capable of amplifying all the way down to D.C..
Edited by germanium - 6/24/14 at 6:57pm