04-12-2013, 11:05 AM
Because of the loading of the triode mixer tube, you may not get a very sharp peak. The normally low triode plate resistance may not allow very high Q in the primary tuned circuit.
You mentioned that the original cap seems to tune more sharply than the replacement. I am curious as to why you are thinking of replacing it?
Typically mica caps are pretty reliable and not prone to the same degradation as paper/foil types. Silvered micas do sometimes become unstable, but from the photo, your cap seems to be the more reliable stacked mica/foil construction.
What type of cap are you using as a replacement?
You mentioned that the original cap seems to tune more sharply than the replacement. I am curious as to why you are thinking of replacing it?
Typically mica caps are pretty reliable and not prone to the same degradation as paper/foil types. Silvered micas do sometimes become unstable, but from the photo, your cap seems to be the more reliable stacked mica/foil construction.
What type of cap are you using as a replacement?