April 18, 2012 at 9:49 PM #1 I changed original tubes of the beast by "Tung-Sol 12AX7 / ECC83 Reissue BALANCED" and "Sylvania 6V6 GT / VT-107A, USA NOS TT XT-Matching".Some profiles with the E906 and other with SM57 Special6 E906Special6 SM57