Tapes are really subtle. Or not, depends from wherever you're coming. Open "dusty old tape". If you're hearing a drastic change, everything's fine technically-spoken. Now go through the Strudels and listen as closely as you can. If your hearing slight hi-end-roll-offs (feeling like 0.2 dB) and the 200 hz-range strangely become solid and slight raspy overtones in the 2k-range, you'll start to realize what all the tape-magic is about - really really subtle ! Do a lot of bypassing/before-after-testing. Null-test might also work copy your track without nebula, flip its phase and mix it with the nebula-processed one. Now listen to the difference.