ish - I would be speculating as well. I have heard that the SSs stay out of the digital domain, therefore accomplishing their requirements in analog, and probably doing it such as you suggest. I can offer no real insight. However, I am still looking to develop a qualified repair station for SmartSubs. I welcome any input from all of you.
Silvanik - Rob at Coherent Source Service does have a CS3.6 XO schematic which I developed from layouts. Rob determines how he shares that proprietary information. We are developing upgrades to address issues such as you mention. Electrolytic caps do drift and fail over time, and there are more sophisticated solutions available today, especially capacitors. I have bought a pair of 3.6s to put in queue behind the PP, 2 2 and 2.4 presently under development.
We have determined to replace all resistors with Mills MRA-12s at unity value for a stand-alone, cost-effective upgrade. However, further changes to layouts, foil coils and lower ESR caps may require tweaking those resistances at the time of further upgrade. The 3.6 work is scheduled in 2019.
Silvanik - Rob at Coherent Source Service does have a CS3.6 XO schematic which I developed from layouts. Rob determines how he shares that proprietary information. We are developing upgrades to address issues such as you mention. Electrolytic caps do drift and fail over time, and there are more sophisticated solutions available today, especially capacitors. I have bought a pair of 3.6s to put in queue behind the PP, 2 2 and 2.4 presently under development.
We have determined to replace all resistors with Mills MRA-12s at unity value for a stand-alone, cost-effective upgrade. However, further changes to layouts, foil coils and lower ESR caps may require tweaking those resistances at the time of further upgrade. The 3.6 work is scheduled in 2019.

