My Boss SD1 mod

[ianlogan123]

I usually check in here everyday to have a read of the new topics, but don't contribute very much (because I don't know that much about electronics!). I thought I would try and give something back to the board, so here are the mods that I've made to my SD1. The changes are based upon bits of Melanhead's mods and Wampcat's from this thread - http://www.diystompboxes.com/smfforum/index.php?topic=37620.0 - , but also my own experiementation. My hand was somewhat forced by my lack of components, but I think this sounds pretty good. It has a little less bass and a bit more mid than some of the other mods I've tried, which I like, and has a nice fat overdrive. In particular there is great seperation between the notes in chords. Some of the components are the same value as the original, but were upgraded as I tried various combinations. All caps and resistors are metal film. I'll put an asterisk beside the value changes.

Part__Original__New
C1___0.047____0.047
C2___0.018____0.047***
C3___0.047____0.1***
C4___0.018____0.022***
C6___0.01_____Remove***
C7___1.0______1.0
C8___0.047____0.047
C10__1.0______1.0
R2___470K_____620K***
R4___100K_____68K***
R6___4.7K_____4.7K
R7___10K______10K
R9___10K______10K
R16__1K_______1K
R17__100K_____68K***
D4___IS2473?___1N4001+1N34 in series***
D5___IS2473?___1N4001***
D6___IS2473?___1N4001+1N34 in series***

I also changed the IC to JRC4558D.

Hope this is of some use to somebody.

Regards,

Ian.

[Stephen]

You can use IN4002 diodes too!!  WELL is it GOOD???

[SpufuZ]

have you tried the RC4558P??
Ive got it in my TS808-clone and its really nice, or so they say atleast! =)

[ianlogan123]

I've got a couple of other op-amps, so some time this week I'll give them a go and let you know if there is a big difference in sound. It sounds pretty good as it is, although I suspect that Wampcat's diode arrangement may be contributing the most.

I'm going to be getting some recording equipment in the next few weeks so will try and post some clips when I can.

Ian.