Boss DS-1

fractal33

Active member
Earlier today I ordered some boss ds-1 clone boards from Aion and about an hour later my buddy came over with a DS-1 and said he would trade it to me for making him a pedal(which I was going to do anyway). Serendipity I suppose. Anyway, it is made in Taiwan and has thru-hole components. An online serial decoder says it was made in '04. Just wondering if there are any go-to mods for this thing I should try out. A quick google search is showing me the Keeley mod. Does anyone have experience modding a DS-1?
 
The mods I did are in 3 places.
1. Keeley clipping mod. Replace one of the clipping diodes (D4 or D5) with a red LED.
2. Tone mod. Replace C11 (22nF) with 47nF. Replace R16 (6.8K) with 3.9K. This gets rid of the dreaded mid notch.
3. CB voice mod. I've seen other people mess with the gain and biasing of Q2, the gain stage in front of the opamp, but no one made Q2's gain or freq response switchable. Until now. Replace R9 (22Ω) with 470Ω. Add a SPDT on/off/on toggle switch and wire it so that it adds either a 22uF or a 2.2uF (or neither) in parallel with R9. With 22uF in parallel with R9, you get the same gain as the stock pedal. With 2.2uF, you get a tighter bottom end. With the switch in the center position, you get less gain and very little, if any, distortion in Q2.
Almost forgot: I increased C2 from 470nF to 2.2μF and C3 from 47nF to 1μF. Fattens up the bottom end. I used tantalum for C2 & film for C3.

The other thing people like to do is reduce R13 and increase C8 for more gain when DISTORTION is dimed. I didn't bother with that mod because I think the DS-1 has plenty of gain already.

DS-1 cb mod 02.jpg
 
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The mods I did are in 3 places.
1. Keeley clipping mod. Replace one of the clipping diodes (D4 or D5) with a red LED.
2. Tone mod. Replace C11 (22nF) with 47nF. Replace R16 (6.8K) with 3.9K. This gets rid of the dreaded mid notch.
3. CB voice mod. I've seen other people mess with the gain and biasing of Q2, the gain stage in front of the opamp, but no one made Q2's gain or freq response switchable. Until now. Replace R9 (22Ω) with 470Ω. Add a SPDT on/off/on toggle switch and wire it so that it adds either a 22uF or a 2.2uF (or neither) in parallel with R9. With 22uF in parallel with R9, you get a little more gain that the stock pedal. With 2.2uF, you get a tighter bottom end. With the switch in the center position, you get less gain and very little, if any, distortion in Q2.

The other thing people like to do is reduce R13 and increase C8 for more gain when DISTORTION is dimed. I didn't bother with that mod because I think the DS-1 has plenty of gain already.
Not gonna lie I’m pretty excited to hear from you specifically. What a great group of helpful people we have here. Thanks Chuck!
 
The mods I did are in 3 places.
1. Keeley clipping mod. Replace one of the clipping diodes (D4 or D5) with a red LED.
2. Tone mod. Replace C11 (22nF) with 47nF. Replace R16 (6.8K) with 3.9K. This gets rid of the dreaded mid notch.
3. CB voice mod. I've seen other people mess with the gain and biasing of Q2, the gain stage in front of the opamp, but no one made Q2's gain or freq response switchable. Until now. Replace R9 (22Ω) with 470Ω. Add a SPDT on/off/on toggle switch and wire it so that it adds either a 22uF or a 2.2uF (or neither) in parallel with R9. With 22uF in parallel with R9, you get the same gain as the stock pedal. With 2.2uF, you get a tighter bottom end. With the switch in the center position, you get less gain and very little, if any, distortion in Q2.
Almost forgot: I increased C2 from 470nF to 2.2μF and C3 from 47nF to 1μF. Fattens up the bottom end. I used tantalum for C2 & film for C3.

The other thing people like to do is reduce R13 and increase C8 for more gain when DISTORTION is dimed. I didn't bother with that mod because I think the DS-1 has plenty of gain already.

View attachment 19193
I'm going to have to modify my spread sheet to fit this one in
 
I think Aion's build doc does a pretty good job of summing up the most useful mods. The mods that are listed for his board will translate to the actual DS-1 or you can search for these online. For my ears the best DS-1 is a silver screw with the TA7136P. I'd recommend that one for the Aion board if you can get the TA7136P, BYOC used to have them.
 
Haven't built the clones or gotten around to modding my DS-1 yet, but I'm starting to wonder if there is something wrong with it or if it just sounds the way it does normally. the tone knob is mud until like 2 o'clock and the output is extremely quiet compared to my other pedals. Is this normal?
 
Haven't built the clones or gotten around to modding my DS-1 yet, but I'm starting to wonder if there is something wrong with it or if it just sounds the way it does normally. the tone knob is mud until like 2 o'clock and the output is extremely quiet compared to my other pedals. Is this normal?

The DS-1 was designed to drive an amp into distortion. It was designed to go into an amp already a bit overdriven. Think of it as a distortion boost.
 
The output is fairly low compared to most pedals. You can definitely get above unity. The stock Tone control is the weakest part of the circuit IMHO. Try the Tone Mod I mentioned above. If you change one or both clipping diodes to red LEDs it gets louder and less compressed.
 
I'm thinking about building an Aion clone tonight or at least starting one. Going to make some notes on the build docs and probably socket a bunch of parts to try some of these mods out. Thanks, everyone!

The mods I did are in 3 places.
1. Keeley clipping mod. Replace one of the clipping diodes (D4 or D5) with a red LED.
2. Tone mod. Replace C11 (22nF) with 47nF. Replace R16 (6.8K) with 3.9K. This gets rid of the dreaded mid notch.
3. CB voice mod. I've seen other people mess with the gain and biasing of Q2, the gain stage in front of the opamp, but no one made Q2's gain or freq response switchable. Until now. Replace R9 (22Ω) with 470Ω. Add a SPDT on/off/on toggle switch and wire it so that it adds either a 22uF or a 2.2uF (or neither) in parallel with R9. With 22uF in parallel with R9, you get the same gain as the stock pedal. With 2.2uF, you get a tighter bottom end. With the switch in the center position, you get less gain and very little, if any, distortion in Q2.
Almost forgot: I increased C2 from 470nF to 2.2μF and C3 from 47nF to 1μF. Fattens up the bottom end. I used tantalum for C2 & film for C3.

The other thing people like to do is reduce R13 and increase C8 for more gain when DISTORTION is dimed. I didn't bother with that mod because I think the DS-1 has plenty of gain already.
Chuck, what would be the best way to go about wiring the caps in parallel via a switch? One lead of each of the caps connected to the net of R9 and Q2 emitter, and the other leads on lugs 1 and 3 respectively, and ground on lug 2? Sorry brain not so good.
 
I built the comet from aion, with mod 1 & 2. I think a TL72 sounds better than a RC4558 in there. I tried to upgrade it with an OPA2134, but I can't really feel any improvements, maybe slightly less gain with pot fully CW... I wonder if it would change anything in the sound if I try the vintage op-amp TA7136P. Has anyone tried both ?
 
Chuck, what would be the best way to go about wiring the caps in parallel via a switch? One lead of each of the caps connected to the net of R9 and Q2 emitter, and the other leads on lugs 1 and 3 respectively, and ground on lug 2? Sorry brain not so good.

Yes, the way you describe will work. I did it this way. Same result because C100 is so much bigger than C101. Note: the stock soft-switching is not shown in the schematic below.

DS-1 cb mod.png
 
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