The Sovtek 5751 is an affordable alternative to the 12AY7 used in original Fender tweed amps and can be subbed for a 12AT7 reverb driver tube. In this application, you will get good gain with a warmer sound than the 12AT7. The even balancing makes them a nice phase inverter and allows you push the front end of the amp a little harder. If you wish to use a 5751 in a 12AX7 position to reduce gain we recommend you use the JAN-Philips 5751 tube.
Special note for 5751 types: The 5751 is not a true 12AX7, but is often used in place of a 12AX7. They only have 70% of the gain of a 12AX7, and are often used to quiet down guitar amps that have too much gain. You can learn more about this on our tone tweak info page.