Effect Pedal Mods

And I though building amps was hard!


WARNING: I am creating this page AS I GO. I can NOT guarantee it is error free. If anyone decides to follow these instructions, please WAIT until the page is done and this warning is removed!!!


The first pedal I will cover is the Boss DS-1. The thing about modding the DS-1 is that there is a LOT of things you can do with it. You can do your popular mods like the Keeley Ultra-Mod and/or the Seeing Eye Mod. You can make it sound similar to a Marshall JCM, or give it 'modern' OR 'vintage' distortion tones, or just give it some small tweeks. So as you can see, as with most things, its personal preference.

Here I will document what I did. See the bottom of the page for credits to those who share information.



And.. for your reference, here is a schematic, with additional info dated Dec. 26, 1980.


OK.. so what do YOU want to do with it? Here is a collection of ideas I've gathered

Keeley Seeing-Eye mod / Ultra Mod (combo) C1,C3,C5,C12,C13 to 0.1uF, C2,C8,C9,C14 to 1uF, C4 to 470pF, C7 to 220pF, C11 to 0.047Uf, D5 to 3mm red LED (ANY LED is OK, R2 to 620K, R13 to 2k4, R14 to 1k5, R35 to 1k, R39 to 20K, D5 - 47pf cap in parallel with LED
Marshal JCM style C3 to .033uF, C2 to 1uF, R17 to 15K, D4 2 1N4148 in series, D5 2 1N4001 in series, C5 & C9 to 1UF
Modern distortion R16 to 1K, R14 to 10K, C10 to .001uF, C5 & C9 to 1UF, D4 to LED
Vintage distortion D5 to LED, C3 to .033uF, R16 to 1K, C11 to .001uF



The Parts Order:
Here is a table I put together with part numbers. You can reference the manufacturers part # on almost any electronic components site.

Item Digikey part # Mfr. part # Mouser part#
0.1uF caps P4525-ND ECQ-V1H104JL N/A
1uF caps P4675-ND ECQ-V1H105JL N/A
.022uF caps P4517-ND ECQ-V1H223JL N/A
1K resistors P1.00KCACT-ND ERO-S2PHF1001 N/A
1.5K resistors P1.50KCACT-ND ERO-S2PHF1501 N/A
3.3K resistors P3.30KCACT-ND ERO-S2PHF3301 N/A
620K resistors P620KCACT-ND ERO-S2PHF6203 N/A
470pF Mica Radial Lead Caps 338-1043-ND CD15FD471JO3 5982-15-500V470
220pF Mica Radial Lead Caps 338-1046-ND CD15FD221JO3 5982-15-500V220
3MM Red LED 67-1402-ND SSL-LX3052ID 696-SSL-LX3052ID
LED Lamp 3mm White 67-1606-ND SSL-LX3054UWC/A 696-SSLLX3054UWC/A


So, Lets Get Started!
Here I will docuement my first DS-1 mod. Well, to be exact, my first pedal mod of any kind!

What I did at my first sitting was change some capacitors. To be exact, I changed:
C1, C3, C5, C12, & C13 to 0.1uF caps, and
C2, C8, C9, & C14 to 1uF caps.

Here is what I did in pictures:



I hope its obvious, the first picture is the 'before' and the second picture is the 'after'. Regarding the replacment caps, for those who are just looking, the smaller red ones are the 0.1uF caps, and the larger almost square ones are the 1uF caps. So... was it all worth the effort? Here are some sound samples. In the sample, the 1st, 3rd, 5th, and so on is a UN-modified DS-1, while the 2nd, 4th, etc. is the modified pedal.

-Sound sample goes here

Summary of first sittings work:
Well, the sound is less 'tinney' or thin, I can tell that. Maybe a better way to say it is that it sounds 'fuller' and more balanced across the sound spectrum. The question that comes to my mind is this: Is the tonal change for the better due to the changing of capacitor values, or capacitor manufacturer 'quality &/or reputation'. To summerize the changes:
Cap Old value New Value
C1 0.047uF 0.1uF
C2 0.47uF 1uF
C3 0.047uF 0.1uF
C5 0.47uF 0.1uF
C8 1uF 1uF
C9 0.47uF 1uF
C12 .1uF 0.1uF
C13 0.047uF 0.1uF
C14 1uF 1uF
As you can see, a number of values have been increased, which normally can be thought of as letting more lower frequencies through -thus the 'fuller' sound.

Also, there is a slight but noticable volume increase as well (asuming the volume levels were the same at the same knob position before the mod - but I suspect they were). I find pretty much no difference other then the above mentioned tonal change and the volume difference. In summary, its a good start.


Second bit of work!
I had some time, so I went ahead and did a little more work. Here is a picture and a table of the work I did this time.
Component Old Value New Value
C4 250pF 470pF
R2 470K 620K
R14 2k2 1k
R16 5k8 1k
R35 x 1k
The yellow dots are the components I changed this time:


Summary of second sittings work:
WOW. Too much bass and even louder. Trying to keep it fair and all that, when I did my initial side by side test, both tones were at 12 o'clock. I ended up having the modded pedals tone turned all the way up and left the un-modded pedals tone at 12. Regarding the volume, I had to tweek the modded pedals volume down a bit. There is a lot more 'umph' (low end) on the modded pedal, which does sound nice. When playing the b & high e string, the lead/single note tone is noticable less 'brittle'. When playing power chords on the low e and a strings, althought the level of distortion is (about?) the same, due to more low end coming through the signal, it sounds a bit more 'powerful' I guess is the word. All in all, I'm happy with the difference in tone thus far, and it seems to keep getting better. The only thing I'm not real happy about is that the tone knob is maxed out and at the current time I could not get any more highs out of it even if I wanted. I'll have to review and change or compensate for that.

-Sound sample goes here

Till next time!