This tube was used as a replacement tube for the ART TUBE MP/C.
It was used for vocal recording only but i guess the effects should also be visible on other acoustic instruments.
It was not much better than the OEM but it certainly is a good tube. it produced a much warmer tone on all levels. when it was overloaded it produced some crackle but if you pay attention not to overdrive it, it is a very nice tube to have.