14-05-2012, 10:06 PM
O.K., a few thoughts.
I see that the input tuning uses a 300 pF variable cap. and that the regenerator tuning uses a 300 pF variable cap. too (albeit padded down: C6, 100 pF). Hence, question: are these two caps. ganged - or does that not matter, on account of the fact that the R.F. tuning is broad enough so that, in effect, it becomes a simple 'peak' control?
I see that you use a 6AC7 from the freq. converter and that you say that it is prone to overload on strong signals. Since the 6AC7 is a sharp cut-off R.F. pentode, did you consider installing a remote cut-off, vari-µ valve instead - like a 6K7G? That way, a simple manual R.F. gain control could be incorporated.
Overall though, an interesting cct. We need to think about how we can get a relatively simple osc. design going to replace the ext. sig. gen.: I'm thinking about that.
Al.
I see that the input tuning uses a 300 pF variable cap. and that the regenerator tuning uses a 300 pF variable cap. too (albeit padded down: C6, 100 pF). Hence, question: are these two caps. ganged - or does that not matter, on account of the fact that the R.F. tuning is broad enough so that, in effect, it becomes a simple 'peak' control?
I see that you use a 6AC7 from the freq. converter and that you say that it is prone to overload on strong signals. Since the 6AC7 is a sharp cut-off R.F. pentode, did you consider installing a remote cut-off, vari-µ valve instead - like a 6K7G? That way, a simple manual R.F. gain control could be incorporated.
Overall though, an interesting cct. We need to think about how we can get a relatively simple osc. design going to replace the ext. sig. gen.: I'm thinking about that.
Al.
