SD-1 Modding project
Posted: Sat Aug 15, 2009 3:38 pm
So, I bought an SD-1 because its 40 dollars and it's very similar to a TS-9 circuit, plus asymmetrical clipping (which I wanted anyways). However, while it sounds great for 40 dollars, I'm way past that stage right now. So I decided to make a Tubescreamer killer out of it. And thus: the BB-1 Big Bird Overdrive was born. I call it the BB-1 cuz its Big Bird yellow
So far only two changes have been made (because I haven't been able to go down to rat shack yet). I will keep you guys up to date on the status, as of right now, here's some pics of the stock SD-1.
I found it very interesting that the SD-1 uses a JRC4558DD OpAmp...as you know this is basically the same chip used in the original TS808 and TS9...I was gonna get an RC4558P just because I thought the stock chip would be some random chinese shit but since it isn't...I'm not sure if I want to replace it!
Mods done as of August 15th are: C6 removed, R2 changed to 1MOhm. Basically increased note definition, clarity, took out some muddiness. Now it sounds like a TS9 with a bit more drive and a bit smoother clipping.
Mods wanting to be done: replace the stock diodes with 1N4001's, put some low-end in (a few caps changed to 0.1uF), maybe switch out the opamp?







I found it very interesting that the SD-1 uses a JRC4558DD OpAmp...as you know this is basically the same chip used in the original TS808 and TS9...I was gonna get an RC4558P just because I thought the stock chip would be some random chinese shit but since it isn't...I'm not sure if I want to replace it!
Mods done as of August 15th are: C6 removed, R2 changed to 1MOhm. Basically increased note definition, clarity, took out some muddiness. Now it sounds like a TS9 with a bit more drive and a bit smoother clipping.
Mods wanting to be done: replace the stock diodes with 1N4001's, put some low-end in (a few caps changed to 0.1uF), maybe switch out the opamp?





