Boss SD-1 mod for bass

screaminglucy · #1 10-10-2009, 07:42 PM

I just finished modding my Boss SD-1 to fulltone bass drive specs. I compared it to the real thing and i cannot tell them apart. Here are the components i changed in the SD-1 in case anyone else is interested in this...

R2 = 620k
C2 = 1uf
C3 = 0.068uf
D6 = jumper (short)
D5 = 1n4005
D4 = 1n914
R7 = 1k
put 47pf across clipping diodes
C4 = 0.22uf
C5 = 0.22uf
R8 = 220
remove C6
R9 = 1k
C8 = 0.1uf
R16 = 100
C10 = 10uf

Flat mids switch adds 47k in series with 0.01uF between pin 1 of the opamp and pin 1 of the overdrive pot (the lug connected to R5)
I also swapped the opamp for NJM4558D

screaminglucy · #2 10-20-2009, 07:37 PM

i also added a blend knob next to the dc jack...using this circuit
http://www.seanm.ca/stomp/minblend.html

pics

and sound clips to come...

bass-shy · #3 10-21-2009, 07:00 PM

Cool! Thanks for sharing. I have an SD-1 lying around. I just might have to give this a shot.

vigor&kandor · #4 10-22-2009, 03:20 AM

is this fulltone with booster on? or off?

is R6 just 100 ohms?

screaminglucy · #5 10-22-2009, 06:18 AM

boost on....gain up to 9 o clock is like boost off. i didnt do the comp cut switch.

r16 is 100ohm

conundrum · #6 10-04-2010, 01:43 AM

What's a good place to buy these parts, a radio shack type store, or Digikey?

screaminglucy · #7 10-04-2010, 07:02 AM

smallbearelectronics is the easiest to find the right parts. otherwise radioshack, digikey, or mouser.

skulletwhip · #8 10-04-2010, 11:53 AM

I gotta ask what a jumper is. I just started building my own stuff and have seen that word a few times.

dune2k · #9 10-04-2010, 12:19 PM

Basically a piece of wire that makes a connection between two points.

skulletwhip · #10 10-04-2010, 12:35 PM

Thats what I thought, but it seemed TOO obvious. Thanks.

conundrum · #11 10-04-2010, 04:59 PM

edit: Maybe a Monte Allum mod would be less complicated for me to start off with.

T.A.P Bass · #12 11-21-2010, 07:11 PM

Bump

Waiting for the clips.

audiomitch · #13 11-21-2010, 11:21 PM

Quote:

Originally Posted by conundrum

edit: Maybe a Monte Allum mod would be less complicated for me to start off with.

I just did the Monte Allums SD-1 mod, but I had guitar in mind. I'll have to try it on bass. Unfortunately, I never use fuzzy bass in real life, so I'll be a poor judge if it's any good or not.

screaminglucy · #14 04-07-2012, 04:23 PM

I'm now using a red llama for my overdrive. I find it retains more low end. It does sound more towards a fuzz sound though.

markxander · #15 04-07-2012, 06:05 PM

Still have that modded SD-1 hanging around?

Shoot me a PM if you feel like selling it ha