Cross reference tubes. The 6GH8 is listed as a substitute for 6EA8. The 6GH8 works at times for the 23 channel crystal mixer. But, for an RF amplifier tube, it does not work well and especially so in Cobra Cam 88 and Knight KN-2565B (same chassis as Cam 88). The best 6EA8 I used for an RF amp tube is older Tung Sol. The Tung Sol is far superior to GE 6EA8.
The exact replacement tube for an 8950 is the 6KD6 with same internal elements with a 6.3 volt filament. The 6LB6 and 6LF6 are slightly different inside, your amp may tune differently and the drive (input) capacitor trimmer if so equipped may need re-tuning for 6LB6 & 6LF6..
Last Edit: Jul 23, 2019 8:24:21 GMT -5 by oldgeezer