What makes the telefuken tube so special?

The sound is rich, full and musical. Tube audiophiles have been using this tube as a reference for years. They are expensive because they are hard to find.

I have 4 12AX7's that I can't use because I've changed gear and my new preamp uses 12AT7's. Contact me if you're interested.

ah tube sound I have heard that one reason NOS tubes sound better is that the chemicals used long ago are very toxic and can not be used today. thes are the things they use to dope the electrodes . I do not know if it is true but seems a good reason could be true ? lake 513

Richness, Soundstage, Bass extension.