Tungsol 5751.
Tungsol premium quality 5751.
Great tube to use in place of a 12ax7/Ecc83 if you want slightly less gain, or where the front end of your amp is too hot..eg Blues Jnr, Hot Rod Devilles/Devilles etc
The 5751 tube has *80% of the gain compared to a 12ax7/ecc83.
