I have a Supratek Sauvignon. I rolled the original tubes to a pair of Tung Sol GTB's circa mid 1950's and the improvement was substantial. The music came alive right across the spectrum. I recently got a hold of a pair of NOS NIB Mullard ECC33's (manuf 1963). These tubes aren't easy to come by and they don't come cheap. To be honest I'm a little disappointed in the sound. I'm aware that the ECC33 isn't an exact substitute for a 6sn7, but everything I've read about the Mullards suggests that they should be fantastic. The sound is a little "slower" and although detailed, it lacks the punch of the Tung Sols. Has anyone else had a similar experience?
