BOSS DS-1 Distortion Mods By Keeley Effects  The SEEING EYE MOD

These are the mods that we have come up with.  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).  We use metal film caps available from

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 we 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 (the power LED that we take out!)  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!

Changes made as of 01-10-03

Thanks to the folks at for pointing out 2 errors in the cap values I had listed.  I had some things swapped around!  So please check your unit if you did the mods before the changes date.  Thanks to anyone else who emailed me about these mods.

Feel free to distribute.

Copyright 2002-2003 Robert Keeley/Keeley Electronics