These are the mods that i will be doing to my Boss DS-1 once it arrives, Mostly they try to give the pedal a more high fidelity sound and make it a little more tube like by use on one LED in the clipping section instead of two (commonly seen as a mod).
C1, C5, C12change to 0.1uF metal film (104) C2, C8, C9, C14 change to 1uF metal film (105) C7 220pf silver mica or monolithic
In the DS-Ultra mod you change C11 to a 0.047uF metal film or better and lower R13 to 2.4Kohm. As well as changing C3 and C13 to 0.1Uf metal film or better.
D5 change to 3mm red led , In the D-Ultra mod we switch in another LED in series with D4.
R39 20K R14 1.5K R35 2.4K if you change the power LED to a 5mm Yellow LED
Add 47pf cap across clipping diodes, see second picture little green dot in the center. 7/64 drill bit needed to drill out 3mm LED for the SEEING EYE PART!