One more fault of many models of the SoundBlaster 16:
At least two models suffer from a rookie design mistake: unterminated (floating) portions of quad op-amps. These cards have at least one part of a quad amp floating with no defined input or feedback, so they generate insane amounts of noise. A link to a topic on why floating op-amps are so bad for noise: https://www.maximintegrated.com/en/design/tec … tes/1/1957.html
(The reason unterminated amps do this, is because without defined input levels and proper feedback, the amps are effectively running with extremely high gain on noise currents, so they flop in the electronic breeze like laundry in a windtunnel. You can imagine this will inject huge levels of noise into the power rails, and often disturb the operation of other amps in the package as the amps in most quad-package amps are not completely independent.)
Fixing this issue is simple but requires some flying wires: on your typical garden-variety SB16 with dual supplies (7805 and 7905 regulators), it's a matter of running the non-inverting input to ground, and bridging the output and inverting input pins together to turn them into unity-gain followers holding steady at around 0V. (Conversely, if you were to fix this problem on a card running the amps in single supply - test the voltage rails with a multimeter first to see if one side is connected to ground - you'd instead hold the non-inverting inputs to 1/2 Vcc to avoid railing the amp low.)
On the first-revision (TDA1543T DAC) CT2760 AWE32, the entire left half of U22, the right half of U27 and the bottom half of U30 are floating. This is significant as it's one of the cards with the 'noisy' CT1701-T mixer chip, and I've a hunch that this is why this card seems so noisy, rather than it being merely the mixer chip. Note the amp's proximity to the CT1701-T as well.
Ironically the cheapy CT3600 SB32 is free from floating amps. If only they all were like that... 🙁
On the CT2940 ViBRA16S, U5 and U7 have floating, unterminated amps at pins 12-14 each. Note that I've already fixed the amps in this picture, just note the pins circled in red.
Unfortunately there are other SB16/ViBRA cards with floating amps, but these two are the ones I have convenient that I know for sure have floating amps. (So please don't ask me where the floating amps are on a CT2770 or CT2230 etc., because I don't know at the moment - I am still finding out just how many of these cards have this problem.)
In any case, finding the 'floating' amps requires removing the amps to see which ones are not tied to anything at all. If there are no traces or vias connecting pins on an amp, odds are extremely good Creative just left that part of the amp to float.
Life isn't long enough to re-enable every hidden option in every BIOS on every board... 🙁