Chris (Cal) thanks for the clarification. In my Frankenstein I replaced the Solens with the Jupiter copper foil capacitors. This yielded a modest improvement overall, definitely subtle. So the Solens is actually quite good as the stock capacitor. The speaker crossover cap change was more significant. You have different Coincident speakers so you may or may not have similar results. In regard to the Frankenstein IMO it’s so well designed/ executed it is really very fine in stock form. Subtly improved is possible but I doubt major improvement. After 10 years in production the Frankenstein MK II has its first update announced several months ago (internal wiring and output transformers).
Charles
Charles