PSUD2 stereo modeling

[ee]

I had seen in a much earlier thread about a ps voltage question someone was modeling in PSUD2 for the stereomour 1. It was suggested to enter 135 ohm as the resistor and 110ma or 3300 ohm IRC as the load since it was a stereo. If modeling with a choke  should I treat it as parallel also for resistance, inductance? Do capacitors get treated as parallel also (eg 100uf looks like 200uf) when modeling PSUD2? My concern is trying to evaluate the graph of the load generated based on which numbers are put in for resistance inductance and capacitance etc. Example, the last ps cap with the triad c7x can go lower (50uf or so) but the graph starts looking wild atleast on startup and bounces around some when current changes. It is a quick bounce before going stable though about 0.45 sec IRC.
Thanks
Eric 

 

[Paul Birkeland]

If modeling with a choke  should I treat it as parallel also for resistance, inductance?

If you're changing out a power supply resistor for a choke, you simply change that node in PSUD from an RC filter to an LC filter.

Do capacitors get treated as parallel also (eg 100uf looks like 200uf) when modeling PSUD2?

A 100uF capacitor looks like a 100uF capacitor.  I'm a bit confused about where the second 100uF is coming into play?

My concern is trying to evaluate the graph of the load generated based on which numbers are put in for resistance inductance and capacitance etc. Example, the last ps cap with the triad c7x can go lower (50uf or so) but the graph starts looking wild atleast on startup and bounces around some when current changes. It is a quick bounce before going stable though about 0.45 sec IRC.

A little bouncing isn't an issue. 

If you're wondering what to do in the model because you have a single power supply being split for each channel, you are correct that PSUD doesn't really deal with that super well.  If you want to look at ripple, just put in the power supply and load for one channel, preserving all the values and being prepared to see a B+ voltage that's a little high (but you're looking at ripple).

If you want to see the B+ that's coming out of the power supply, use the demand from both channels and the equivalent parallel resistance of each channel.  If you had a CLC for each channel with a C7X (270 Ohm 10H), you can put a CLC in PSUD with a 5H 135 Ohm choke.  Provided you use  the actual values in the amp for the voltage doubler, the size of the filter cap after the choke isn't super critical for getting an estimate of the B+ value (use either 100uF or 200uF).

-PB