Thanks, Evan. It would be extremely unlikely that the adapter would PASS the appropriate energy being developed at the fundamental frequency any differently than the spurs and harmonics that it is also passing.
In weeks and weeks of work on the DE model (that now is? working well) the only "bad connections" that I experienced in the meaurement chain were when solder migration literally disconnected one of the push-pull final MOSFETS!!? ?The drain connection apparently got hot enough to allow plastic-like flow of my low-temp solder!? ? One I switched to the AlN insulators I didn't see this again, which MIIGHT be their better conductivity or just less hours.? ?I've been using that rig now for a bit and no problems.? ?
All I can say SO FAR is that Serial # 141 has problems.? ? Definite problems.? ?Increasing the idling current made big improvements in some of the problems.? ?I suspect I have "bad connections" problems similar to what you observed, that are adversely impacting the workings of the filters.....speculation at this point.? ?Further testing may isolate the culprit.? ?
Manufacturing tolerances (e.g. the variations in threshold of different MOSFETs or the differences in gain of different transistors) and variations in physical alignment, connection make manufacturing quality control difficult (I think; I'm not an expert!).? ? Taking a snapshot random sample of ten produced units and extensively testing them might give an idea of the mean and standard deviation of performance, but this would be a solid week worth of work, I fear.? ? That's the advantage that a big company like ICOM, with an ARMY of engineers and manufacturing engineers, and quality control engineers, has over a small shop like HFSIGNALS.? ?We, in the community, can fill in as volunteers for some of those positions....but then, I'm not well trained there!? ?And we each have different skills and assets we can call upon.
When the FLEX units first came out I believe they had HUGE problems that weren't discovered until people started poking around.? And those were VERY expensive units!!
Gordon KX4Z
