Hi Pierre,
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PSUD2 should be able to deal with this for you. If you measure the leg of the transformer at 70 ohms, simply add the required resistor value (100 ohms) to give your secondary of 170 ohms.
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Double click on the transformer icon to access the transformer properties box:
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The press the [...] button shown by the arrow. This will bring up the Source Impedance Calculator:
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Enter your off load voltage on one leg and the winding resistance, again for one leg. In reality, you may find the two secondary legs have a different resistance so just average two. Note that I've used 170 which is 70 plus the 100 extra. PSUD (in this example) calculates the source impedance as 230.6 ohms, however it is taking the effect of the primary into account too.
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Click OK and it will feed the transformer parameters back to PSUD2 and you're good to go.
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Having a small input cap on CLC filters is OK, it helps to increase the conduction angle and reduce the peak current in the rectifier. Hope this is helpful.
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Regards,
Duncan
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