03-06-2020, 07:08 AM
Thanks, Geordie. An interesting circuit. Two transistors (BJTs) so there is a "working" g2 pin. The first transistor driving g2 and also acting as a buffer/emitter follower to the o/p stage otherwise the input impedance would be too low. Anyone like to explain why it works with a negative bias?
One valve I'd be tempted to simulate is an 1L6. A DK92 will work at MW and lower frequency SW as a direct plug in despite possibly different construction and different names on the pins. The capacitances are wrong for the higher frequency bands though it does have the performance. The DK40 was used in Europe / UK before the DK92 as the DK91 (1R5) isn't great. The DK96 is also inferior to the DK40, DK92 and 1L6 for HF. People have hoarded the 1L6 so they are stupidly expensive. The 3rd party FET based replacements are also expensive.
I've not been able to find B7G plugs and my homemade attempts are poor.
One valve I'd be tempted to simulate is an 1L6. A DK92 will work at MW and lower frequency SW as a direct plug in despite possibly different construction and different names on the pins. The capacitances are wrong for the higher frequency bands though it does have the performance. The DK40 was used in Europe / UK before the DK92 as the DK91 (1R5) isn't great. The DK96 is also inferior to the DK40, DK92 and 1L6 for HF. People have hoarded the 1L6 so they are stupidly expensive. The 3rd party FET based replacements are also expensive.
I've not been able to find B7G plugs and my homemade attempts are poor.
