There is a thing call safe touch voltage or "extra-low voltage".
Typical minimum skin resistance is around 1.6k and 30mA can kill you. so 1600x0.03 = 50v.
50VAC RMS is the standard for "extra low voltage" and the maximum voltage you can safely touch with your bare hands.
This is another topic altogether and far from what a sound card can produce.
The point is to get clean audio signal and stay in the standard voltage line levels to prevent distortion without knowing anything about the circuitry of the interconnected hardware, that's why there is a standard.
Electrocution is not of any concern in this matter, clean distortion free audio is.
Yep the mod really improves that awful 'dry' output, well done James.
Yeah, I'm waiting for other people to do the mod and report with cheerful posts. 😀
EDIT: For those who already bought 4.7nF caps, the sound will be somewhere between the SB2.0 and SBPro which will sound great.
From what I hear the SB2.0 is slightly less filtered than the SBPro, but not entirely without a filter like some believe.
The Sound Blaster Programming Guide states for the SBPro (CT1345 mixer):
Turn off the filter for high sampling rates or stereo output.
Indeed I have encountered games that sound really muffled with the filter enabled like Duke Nukem 3D which uses SBPro Stereo and high sampling rates, it dos not disable the filter automatically.
Other games like Doom, Heretic, Hexen, Archon-Ultra, Descent, automatically enable the filter when entering the game.
Most older games don't care if the filter is on or off, but expect it to be always On like on the SB2.0.
It is safe to say that with high sampling rate games like Duke3D the filter should be off, but most games switch the filter on/off and Stereo mode automatically as they need, Quake is one of them.
In other words, if the developer was aware of the SBPro Stereo switch, here was also aware of the Output Lowpass filter switch which is available only on the SBPro.