The previous entry was made in 2002. I am certainly the late comer to this portable stax party. Please bear with me.
I started my stax career with a SRX Mk3. Loved it so much, I ebayed another set (SR44) the other week, not as good as SRX, but still offered excellent sound for money.. Then, I saw these SR001/Mk 2 and SR002 sets. Which one to buy was my question. Instead of waiting for advice, the easier and more efficient way was to buy than all, and left others no time and chance to take them, or any one of them away.
Since then, I have been listening to both and tried different combination, playing 002 with 001 driver, or vice versa. In short, I consider the sound difference between 001/Mk2 set and 002 set is not that much as suggested by their names. Bear in mind that 001/Mk2 uses a 1.5 micron thick diaphragm, 002 uses 1.35, when they are played using 002 driver, 001/mk2 sounds more like old electrett headphones (e.g. pioneer se 500 type with just adequate bass. yes, bass was there, but not punchy). 002 sounds more balance and rich with that little more bass. Then, when they are played under 001 driver.. OMG, 002 sounds so much like my 507 on 006t. Everything improved. 001/mk2 also sounds better using 001 driver. A mix and match suits me better.
I suspect that when Stax updated the 001/Mk2, their main considerations are power consumption and portability. These are also the two areas when more noted improvement can be felt. I am solving the power consumption problem by using a 5v/1a power bank and the charging cable of my old psp. not 100% sure how that additional 1v power input makes the difference. I subjectively feel that using power bank gives better sound than using 14500 battery (3.2v), which is way better than using rechargeable batteries (1.2v x2).
My portable stax journey is still on going. I bidded a pair of broken sr003. The reason for making the purchase is to get a stax cable cheap. Many of you might not aware, the cable of 001/mk2/002/003/005 are interchangeable. With a cable from a 003, I can play my 001/mk2 and 002 on my 006t. it will be interesting to see how they compare to their big brothers.