[bikerhifinut]

Thanks for the responses, much appreciated.

I did a remodel on the Duncans amps PSU2 software.

I know the transformer has a DC R of 7 ohms so i use that, likewise the chokes are 100 ohms each and effectively would be in parallel as they'd split the supply after the first reservoir capacitor downstream of the rectifier. So I assumed a DC R of 50 ohms for the chokes.
The capacitor data gives 200 milliohms ESR.
I reduced the capacitance of the first reservoir to 100uF and made the capacitance after the chokes up to 470uF each side, I also ran it as a parallel circuit assuming 1000uF after the choke which would be 2.5H at 50 ohms DC R.
The simulation showed the ripple current across C1 ie the reservoir to drop to around 500mA. I assume the resustance of the chokes slows down the inrush/charging current to the big capacitors and the ripple is reduced sufficiently to not cause any big effects.

But the question is, does this present any advantage on High transient peaks or does the presence of the resistance of the chokes slow down recharging time sufficiently to cause problems when the amp is responding to high peak levels?
I think there would be no audible and little measurable advantage in terms of hum as a simple 50uF-5H -50uF filter renders the amps virtually silent as is.
I am interested in the findings that paralleling capacitors increases their capabilities of handling ripple and as I already have plenty of high quality F&T 50+50 uF capacitors with a very high ripple rating, I am tempted to make a single 200 uF reservoir from 2 of these as I have the holes already made in the top panel. The question then is, do I need to have at least 100uF on each stereo channel after their respective chokes, or would 50uF be enough as part of the C L C filter? post this inital PSU filter the capacitors form part of a series of RC filters formed from voltage dropping resistors and their associated bypass capacitors and their values are not so critical although I will likely keep them at about 50uF as that is the values I have at 500V DC Wkg. I could argue that the HT voltages are at about 350 and 150 V respectively but my feelings are using silicon rectifiers in particular means the full HT could be applied across all PSU capacitors until the valves start to conduct and the voltage through the resistors drops.
Thanks for the warning about initial inrush current into very high reservoirs too, does this mean a trial and error on mains fuses until I get a value that doesnt blow on switch on? Normally i would calculate a rough current draw based on the amplifiers power needs and use that as a starting point for slow blow (T) fuses and use the smallest value available that didnt blow on switch on.
On that subject, I have seen designs that put a resistance in series with each diode of around 10 ohms, I suppose thats a form of inrush current limiter? I'd only lose about 1.5V through each diode so thats a bearable trade off. I'll also be putting a high voltage 10nF capacitor across each rectifier diode to suppress switching spikes.

Many questions again sorry, as I said before I am attempting to gain a better understanding of what is actually happening in the circuit rather than just following a "recipe".

Andy.