 Type : 6BW7 Valve Code : Factory Code : Remarks : This is an equivalent to the EF80 general purpose RF pentode. A bit noisy for audio applications although it has been used. |
 Type : EF83 Valve Code : 4G Factory Code : D Remarks : Marked "Imported" this was manufactured at the Valvo Factory in Hamburg, Germany. The EF83 is a vari-mu (remote cut-off) pentode design for audio use in, for example, AGC circuits in tape recorders. |
 Type : EF86 Valve Code : 8Y5 Factory Code : L Remarks : Marked "Foreign" this was made in the Mazda factory in Brussels, Belgium. The EF86 is a purpose designed low-noise pentode for audio applications. |
 Type : EF86 Valve Code : 213 Factory Code : Remarks : This has the famous Telefunken diamond on the base. Notice how different the construction is to the Mullard examples. |
 Type : EF86 Valve Code : -- Factory Code : B Remarks : This one is British, made at the Blackburn factory. |
 Type : EF183 Valve Code : I4 Factory Code : B Remarks : Another Blackburn made, British valve. A vari-mu, frame grid, RF pentode. Not suitable for audio. |
