Pay as per month with Paybright
The Chinese (Sino) 12AX7 tube (made by Shuguang) is popular with Marshall owners for its gain and bite. It is currently re-branded by Penta, Ruby Tubes, Groove Tubes, and many others. Regardless of the name, they are all the same.
Note: These tubes are often not labeled or Shuguang labels them "12AX7" only, and does not include the "A" suffix. However these are "12AX7A" tubes.