the CV378 sounded pretty medocre in the WA6-SE, while its a pretty good tube, its still rather slow and lacks energy, bass is full bodied but also tends to have some bloat to it. i did not think it suited the WA6-SE very well. rolled off too much and didn't smooth the rest out like i thought it would, just made it hazy and slow, the mids still had a bite but the sound was slow, confused almost, with the dynamics of the woo and the slowness of the CV378, while i thought it would work well together, it actually didn't.
basically in WA6-SE, the CV378 is slightly better than sophia in clarity and tubeyness, but its also slower and more boring than sophia, while not really improving a whole lot.
the older "Cossor GZ37" (fat bottle version) sounds much much better and like you said, better clarity/ impact/dynamics/and tight strong full bass. this is basically what i would consider the NOS version of the sophia, similar sound, but much more transparent and with deeper stronger bass and more layering and coherence.
the CV593 is much better in the WA6-SE than the CV378 by the way, and half the price!
Edited by Dubstep Girl - 3/24/14 at 11:31am