I tried the Mullard 4003 tubes years ago sourced from Kevin Deal. They sounded fine (a bit rich) but became noisy faster than expected from experience with other tube brands.
I have been using Ron Sheldon's Cryoset Gold Lion 12AU7's but since Ron's unfortunate illness caused him to shut down his business, I just purchased a matched pair of new production Tung-Sols from Tube Depot. When the time comes we'll see how they sound.
I may be a bit fortunate in that my tube gear doesn't seem that sensitive to the tubes used. More a question of longevity rather than tonality. I suspect from the experiences of others, that Power Tubes have a greater impact on tonality and dynamics.
I have been using Ron Sheldon's Cryoset Gold Lion 12AU7's but since Ron's unfortunate illness caused him to shut down his business, I just purchased a matched pair of new production Tung-Sols from Tube Depot. When the time comes we'll see how they sound.
I may be a bit fortunate in that my tube gear doesn't seem that sensitive to the tubes used. More a question of longevity rather than tonality. I suspect from the experiences of others, that Power Tubes have a greater impact on tonality and dynamics.