I just got in the set of preamp tubes that I ordered from Dougs Tubes today. I have the Tremoverb head so with his advice I went with a Tung-Sol reissue 12AX7 in V1, a Sovtek 12AX7LPS in V2, and Shuguang C9's in V3, V4, V5, & V6. All I can say is WOW!! What a difference that made. Tons of bite...