Nice article, made me think of some hints to give PT owners who like to 'get under the hood'
Very interesting piece, and no doubt very enlightening for those who insist on messing with crappy AC motors, you have to jump so many hoops and spend more money than it's worth to get them to run smoothly (think Atlas, Lingo, etc). There's one thing you can't get away from and that's the fact that AC motors want to vibrate, inject stray fields into the deck and generally add noise right where you don't want it. It also means you have an alternating magnetic field somewhere near the cartridge which can't be a good thing. The designers who I respect such as Arthur K. of PT/Funk Firm and Mark Baker of Origin Live have it straight - DC is the way to go. However, you clearly know your electronics so I raise my hat to you for showing alternatives to PT Too owners whose PSU may be dead or otherwise unsatisfactory.
I bought two PT decks off Ebay, the earlier one, PT 2296, is the one I kept as it's got a beautifully-polished teak plinth with the little pink triangular perspex logo on the front (there's a hole through the plinth behind it, might put a lamp in there one day) and a pink-tinted lid. It was "upgraded" (haha) to PT Too spec by its previous owner. Still with its original box, and what's more I went all the way from Norwich to Brum on a train to collect it. Man did my arms ache when I got home!
The other one, PT 4212, a DC version, arrived with a broken lid and several other issues, but it all worked out well in the end as this one had the HR-100S on it which I still have. To cut a long story short, I rebuilt 2296 with all the DC kit and the chassis and bearing from 4212, added the Alphason and Music Maker 3 and haven't looked back since. As a side benefit, I put 4212 together with the PT Too bits and sold it to a mate for £100 so we both won in the end.
To this day, 2296 runs sweet and true and never fails to give me a smile or a tingle, plus it looks dead gorgeous (4212 was un-logo'd and rather plain-looking by comparison). Bass (especially) on the DC version is much more intelligible and 'organic' without any hint of 'one-note' syndrome. I love this deck so much as it's now totally original, and being an early version has the better (IMO) hard acrylic suspension supports and wedges, later ones are made of nylon and don't feel as good when you slide the parts against each other. Being an engineer means I'm a picky SOB when it comes to materials and construction standards
Might post my hints in another topic as this little ramble is in danger of straying far from its intended direction
PT Vector/HR100-MCS/Shinon Red Boron, ANT Kora LE MC, Unison S6 MkI, Opera Callas SP, speaker cables by Ecosse, interconnects by StraightThru and Ag Audio