Here comes the main advantage of the 101 (vs. the hype and very expensive full-size 1001's): you can get the little 101 all day long on ebay for $15~$20 shipped. If you need more than one, there is even an Ebay store that whole sales the 101's for $20, shipped.
I am also modding a SCPH-1001 to the extreme. I will compare them after both are fully modded. Probably in two month or so.
1001 vs. 101, non-SQ related:
First of all, I will have to say the little 101 is a much better engineered machine. There are only 6 screws to undo, and the components literally disassembles themself once you seperate the top and bottum cover. Very easy to work on. (on the other hand the large SCPH-1001 has many many pieces and many many screws...).
The transport mechanism of the 101 is mounted on three struts which are part of the bottom cover. This make it super easy to damp the transport without altering the look of the machine, all you have to do is attach the dampening material directly to the bottom surface, just that easy... Meanwhile, the well-received full-size SCPH-1001 has the spinner thingey sitting on top a piece of thin sheet metal, it will be very difficult to damp -- no room on top, and under the sheet metal is the circuti board, so no room there either. (Now, if you are willing to completely recase the larger 1001, the "sit-on-top" transport mounting style allows easy mounting to a piece of solid wood block or marble, all you need is an extension on the flextap.....there might be more on that in the 1001 thread)
Unlike the PS-1001 which uses a AKM DAC chip, The PSOne integrated the DAC function into a big CXD processor chip. Left and right audio signal then goes to the 3527 (no data sheet available whatsoever). There are a pair of 0.82uf caps at the inputs of the 3527. Some web info indicated that 3527 is a I/V stage, but how can the I/V use capacitor at input? To find out if the 3527 is actually just a current buffer, I did a signal tap at the 0.82uf caps, and pipe out the signal to the outside and used a pair of VitaminQ for DC blocking.
signal tapping (this is just to figure out the type of signal it is, it is not the official mod).
--signal wires are teflon insulated SPC, ground wire is thicker solid OFC in teflon.
--The 3527 chip is easy to find, it is near the rear of the machine, right next to the "sony computer entertainment" chip. The yellow thing at the corner is the power jack.