The Preferred Series 12AX7 vacuum tube is a versatile, quiet amplifier tube that will be at home in just about anyone’s guitar or HIFI rig. In a Fender Champ they displayed no microphonics or rattling, and had a warm, smooth character that can still get rowdy when driven. The detail is all there as well.
High gain enthusiasts will appreciate the lack of microphonics (despite the fairly large plates) and quiet operation, along with their thick yet precise tone. There is nothing cold or sterile to be found here.
If you want an upgrade from your amp’s stock preamp tubes and aren’t quite sure where to start, you can’t go wrong with the Preferred Series 12AX7.