Right butit's not "lack of regulation" - it's where the regulation happens - I use regulation before the supercaps because outputting power direct from supercapacitors (or batteries) makes a significant difference to having a voltage regulator on the output. It's not just about being limited by the power handling of the regulator but rather about the way regulators handle dynamic current delivery.
As regards capacitors, AFAIK,
- The Uptone unit uses two banks of 7 10F Nesscap supercapacitors in series to increase the voltage handling capability of each bank to 7 * 2.7V i.e about 19V but this is regulated down to 12V max, I believe @ 1.1Amp max current output
-The downside of this is that the capacitance is decreased from 10F to 1.4F. More importantly each 10F supercap impedance is 26mohm & 7 * 26 gives 182mohm
- For 20V PS, I use 8 * 350F Nesscap supercapacitors in series to give a total of 47F & 20V max. The impedance of each 350F supercap is 3.2mOhm so 8 * 3.2 is 25mohm
- For 5V PS output, I use 2 of these 350F supercaps giving 6.4mOhm
- the importance of impedance is that the lower the impedance the faster current is delivered.
One has to bear in mind, however that these low impedances are probably moot as the power has to travel through pcb tracks, wiring & cabling (& usually other voltage regulators) before the power reaches the actual components (In my audio devices I avoid, as much as possible, regulators between power & components). Having said all this, raw supercap power seems to make a difference when powering audio devices which is audible.
The supercap PS must use a charger voltage rating which is 2V greater than the rated voltage output of the PS. More powerful is better just to ensure that the supercaps are always fully charged when in operation i.e there's no possibility of a sag.
The other aspect is that when supercaps need to charged up from low charge (initially or when unit is off charge for a week or more), a more powerful PS will ensure the PS comes up to its rated output voltage in less time - we are only talking about 5 mins or so, anyway. The recommended operation is to always keep it on charge.
I plan to use as a charger my most powerful PSU in the voltage range with a 2.1 plug and use a 2.1 male to male lead with a 2.1 female to micro USB adaptor for the output to the Qutest. I assume the connections on your PS (in and out) need 2.1 male plugs and are centre positive?
This is a post from the Qutest thread on Head-fi by Rob Watts the Chord DAC Designer. I'd be interested in your comments:-
"One benefit of super-caps is that it lowers the PSU impedance, and hence reduces the distortion crosstalk feed from the PSU. But this problem is eliminated with Hugo 2 and Qutest's PSU arrangement of regulating out from a boost voltage - so now the gain section is fed with clean power, eliminating the distortion that comes through the power rails. Of course, you have the benefit of huge current delivery from super caps - but that is not needed for a DAC."