My own observations in working with this block are that area tends to impact the low frequency part of the signal. Larger areas tended to give better low frequency handling. Also, it depends a little bit on the application. Like physical circuits, transformers have a number of uses, from pure amplification (voltage step up and step down), to non-linear response (pushing into saturation), phase rotation (power factor correction for capacitative loads, though normally it’s inductive loads that need correcting), filtering (LC, LR and LCR filters), and probably not relevant to VSIG, isolation. Increasing turns (with a fixed ratio), tends to increase “power” handling, though you can drive it pretty hard before you get audible distortion. My algorithm needs input gain up around 40dB to distort (though if you reduce area and turn to very low values, it can distort at much lower levels).
Looking a the documentation in VSIG, the xformer block at its heart seems to consist of an integrator with flux passed to a differentiator (which makes sense). One approach to modelling transformers requires consideration of the voltage and amperage in the 2 coils, the core leakage and an assumption about the output load. I’m not sure what assumptions they have made on core losses or output load. If you want to reduce audible distortion, don’t put too much gain into the input, keep the area well above 1 (probably 5+) and turns above 1000. Saturation level will depend on if you want a clean amp (then set this to 1), or if you want colour (then set this lower).
Your guesses are good guesses – but they don’t accurately reflect what’s happening under the hood. The documentation is obtuse, xformer’s lineage is actually quite different from most of our other modules. What’s really frustrating is that the controls don’t always do what they say they do in Vsig’s documentation.
I heavily encourage y’all to sit tight, we are actively looking at the xformer module, its control structure, potential uses, alternative saturation models, and overhauling xformer’s documentation to better reflect what’s happening. In the meantime, I encourage users to follow the advice in my last post here.
