Boss - SD-1: Keely & Clay Jones mods

A forum devoted to mod, tips and suggestions for upgrading and rehousing your VERY CHEAP commercial stompbox to near boutique excellence.
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TragicTravisty
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Post by TragicTravisty »

anyone know what the component changes are for a keeley mod? also, ive heard the fulldrive is based on this. if so, is it possible to turn an sd-1 into a fulldrive?

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floris
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Post by floris »

SD1 Keeley mods:
https://www.diystompboxes.com/smfforum/ ... ic=60901.0

"Sd-1
***** SD-1 5-Star Ge Mod ****
Board Number New part Old part Reason
C10 --> Metal Stack Film 1uF, remove electrolytic, increased fidelity,
C7--> Metal Stack Film 1uF, remove electrolytic increased fidelity,
R6 --> 2.4k ohm metal film, 4.7k, increased distortion
C3--> 0.1uf metal stack film, 0.047uf, fidelity and bass response
C2--> 0.1uf metal stack film, 0.018 fidelity and bass response,
R2--> 620k ohm metal film, 470k ohm, increased input impedance, better bypass,

Add 47pF cap across diodes in clipping section to smooth out distortion, just like TS9,

On some older units, short out D3 and the 470 ohm resistor in the power supply section to increase the voltage to the circuit. This increase the headroom and gain. Newer units have it shorted already.

Here is the tricky part of our mod, take a germanium (Ge) transistor and use the Base-Emitter junction (legs) of the device and use it in place of D6. If you use a PNP transistor, the Base will be the negative or cathode side, the Emitter will be the anode. Here is a diode drawing Cathode---|<----Anode. This increases the amount of distortion produced by the pedal, it also sound really nice. Try this! Don't leave it out! It's fun. Get your Ge transistors from Steve Daniels http://www.smallbearelec.com

If you want to drill out the LED and install a 5mm big job, change R30 to a 1.2k-3.3k ohm depending on brightness and battery drain you want, replacing the stock 3.9k ohm."

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TubeDude22
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Post by TubeDude22 »

Instead of starting a new thread, I'll just add this info here. A friend asked me to look at his Keeley modded SD-1. Attached are some pictures. This is a Keeled modded MIJ Boss SD-1. The red LED indicator has been replaced with a blue LED. A hole has been drilled in the top and a mini toggle switch has been installed. It is wired to the clipping diode circuit.
Attachments
IMG_0539cr.jpg
IMG_0538cr.jpg
IMG_0537cr.jpg

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gght
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Post by gght »

Find the SD-1 to Clay Jones mod on this board. It’s a little involved, but turns it into a great pedal.

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gght
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Post by gght »

Found it!

analogguru wrote:
Don´t forget to change the tone-control. Since I don´t have the time to draw that up, here are the steps for the (non-mojo) basic Jones-mod:

1.) Remove R5 - R9, C2 - C6, D4 - D6, IC 1
2.) place a jumper wire instead of D5
3.) assemble a socket for IC1
4.) assemble R5 = 10k, R6 = 1k, R7 = 1k, R8 = 220 Ohm, R9 = 1k
5.) assemble C2 = 100n, C3 = 220n, C4 = 220n, C5 = 220n, C6 stays empty
6.) solder a 10k resistor in parallel to C4
7.) assemble the 2 red 5mm LED´s in D4 and D6
8.) take a chip of your choice (OPA2134) and plug it into the socket.

Now you have a (non-mojo) Jones-SD-1 and saved more than $1.450,--...

analogguru

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Ichabod_Crane
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Post by Ichabod_Crane »

How change the tone control? It means the pot?

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gght
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Post by gght »

I didn’t do anything other than the steps outlined. No change to tone control. Pedal is great

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