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