So my OTL HPA project backend has moved to a class A circlotron. Actually two - one for tube and one for a pair of helper BJTs. The design is based on using the tube output rather than tube input into the base of the SS output stage. The idea seems to work, at least on paper/LTSpice. It also seems to scale between 32ohm to 600ohm however I still need more experimentation. However before that - I need to tackle the DC offset.
(ignore the spurious labelling of resistors)
Broskie has used a pair of cross linked LPF from in the input to the opposite phase to balance DC but I'm interested in alternatives and if the added complication of say active opamp makes a difference.
I suspect I'll need to use two - one for tube DC offset and one for SS offset with the risk of oscillations.
(ignore the spurious labelling of resistors)
Broskie has used a pair of cross linked LPF from in the input to the opposite phase to balance DC but I'm interested in alternatives and if the added complication of say active opamp makes a difference.
I suspect I'll need to use two - one for tube DC offset and one for SS offset with the risk of oscillations.