Pye D16T

[Geordie McBoyne]

The 6BL7GT can be considered as a replacement for the hard to find ECC34 in the Pye B16T.
From the Radiomuseum:  https://www.radiomuseum.org/tubes/tube_6bl7gt.html
The valve was designed specifically for television frame timebases and the characteristics of the two triode sections are not identical. A low power section for the oscillator.
The 6BL7GT was used as the frame oscillator and output in the RCA CTC2B colour TV set.
The later 6DR7 has the B9A base. 
                                                                          From the Radiomuseum:  https://www.radiomuseum.org/tubes/tube_6dr7.html

Geordie McBoyne.