Internal Power Supply Technology Changes since 1999?

Though I am not an expert, I think much has changed for the better since the turn of the century.
I own a lot of McCormack equipment, and can attest that Steve McCormack constantly updates his updates as newer/better parts become available-sometimes, he will be installing different parts than the month previous.
So, the point I am making is that, Yes, there have been technology changes since 1999. Whether they are worth upgrading to, is up to you.

Thanks gdnrbob.I agree with you that technology is constantly evolving. I'm wondering about the specifics that have allowed the miniaturization of internal power supplies in very high end preamps.

The major diff, I think is the advent of switching / digital PS that take up less circuit board real estate (and don't get hot, to boot). As to the smaller size, surface mounted technology allows the use of very small components and take up a lot less space than before (smd). Another thing that has changed is the price: top-fi, hi-end items are priced beyond our solar system nowadays!
SOUND wise, however...it all depends; the actual amplification circuits haven't really changed... So unless the components are tired and need a change (say, the electrolytic caps in the PS), you may not find significant improvements in the new equipment. To be fair to new stuff, hopwever, i find that newer speakers are much better than most vintage ones; likewise with digital players.

I use an older very high end preamp with a separate power supply that is the same size as the preamp itself. .
The same manufacturer now makes better preamps,without the external power supply, that are about the same size as my preamp. What have been the technology changes that have simplified and presumably improved the power supplies?

ptss,
it is very likely that your very old hi-end preamp was made well before 2008. Pre-2008 people spent more $ on hi-end whenever they had discretionary income. All that changed post-2008. The point being your preamp manuf could make a cost-no-object preamp in a 2-box chassis & have a good chance of selling a few. These days that happens much (or much, much) less. So, one thought that I have is that your preamp manuf wised up & is creating the same preamp in a 1-chassis box so that it is less costly & more appealing (cost-wise) to consumers. There might be a compromise in the sonics but what's better - sell a 1-box preamp with some sonic degradation (if any) OR not sell a very costly 2-box preamp?

Are you sure that the newer 1-box preamps also use a linear power supply like your 2-box preamp?

With the advancement of technology esp. capacitor technology, cap sizes have gotten smaller for the same capacitance. That means a large power cap can be put in the same spot to do more filtering & create a smaller ripple DC power rail.
HEXFRED diodes (used in the bridge) have also become better in terms of higher voltage handling capability, faster recovery & spewing less RF content. This means the diode bridge is now much less of an RF generator.
Additionally, many good power supply designs use a small snubber capacitor to contain the sharp rise in voltage when the current flow stops  flowing in the AC waveform as it comes off its pos & neg voltage peaks. This too contains the RF & EMI emanating from the power supply.
Another thing i've seen is that newer power amp & preamp designs use local capacitance to filter out ripple & RF transients. You see this in many  preamps once you take the lid off - a huge array of smaller computer grade filters on the preamp board (or amp board). This local filtering makes the active circuit less sensitive to RF.
Designers use a lot of metal shielding to compartmentalize the power supply. You see this design approach a lot in Audio Note UK components where there is a metal wall separating the power supply section from the preamp section. When the top lid is screwed down the metal wall makes contact with the bottom & top plates which are grounded. So, any RF/EMI finds a low impedance path to ground via the chassis thereby sparing the preamp section. All these items allow the power supply section to reside in the same chassis as the preamp section thereby allowing a 1-box solution.
Hope this helps. FWIW.   

Thanks Bombaywalla. I'm using a Spectral DMC20 and happy with it. But,my efforts on AC power improvements have shown that this preamp benefits enormously from "ultra clean" AC.(Naturally my amp & sources are also provided ultra clean and isolated AC) This fact proves to me the preamp itself is "vastly" superior to it's power supply.When I spoke to Spectral about my experience with my refined AC supply they commented that the unit was designed exquisitely for precision DC output but was not designed as a basic filter for AC, so the better the AC the better the preamp would sound.  I use units that reduce differential and common mode noise and both contribute significantly. Are there components in the PS that would benefit from the latest iterations; or is it possible that the excellence in providing precise DC; when fed by pristine AC; has not changed that much?