hog´s foot bass boster breadboarding

[eaea79]

I started to use a breadboard with some Perfboard projects from general guitar gadgets,

http://www.generalguitargadgets.com/richardo/perfboard/

I tried the "E-H  hog´s foot bass boster" and It worked fine, I decide to change some
components in order to see if it would change anything, but nothing changed.
I changed the 2n3904 transistor for 2n5401, 2n5551 and tried without trnasistor and it
still worked in the same way. Moreover I change the original value of R4 (390) with diffferent
values, 470k,100k,15k,8,2k, 10 ohm, etc, and there were not changes.

My questions are, what do I have to change in order to change the sound of the booster, and why
it behaves in the same way  without the transistor...