TAD 12DW7 / 7247 "Premium Selected". The TAD 12DW7 / 7247 is our “Premium Selected” tube that contains two sections. One section is close to a 12AX7 / 7025 while the other is close to a 12AU7 / ECC82. This 12DW7 / 7247 tube is a faithful reproduction of the NOS 7247 and can replace the ECC832. Used in older Ampeg amps.