Thank you for all your replies. I don't know how big the difference between VT100 and VT100 MKIII, or VT100 vs. VS115? There are not a lot of positive feedback on VT100, but I heard good things for VT100 MKII/MKIII. I feel comfortable on biasing VT100. If there is not a big difference, i'd rather keep VT100. Do you think NOS driver tube on VT100 can significant improve the SQ on VT100?
