Boss SD-1 to TS808 THE REAL WAY!!!!

[Papa_lazerous]

I own an SD-1 and its got a lovely sound, I wouldnt want to make it into something TS sounding, I would just build my own if I wanted one so a +1 to whoever said it first.

Only one big flaw in the SD-1 I dont like and keep meaning to fix.  Is when the drive is up full and you bypass the pedal you can still hear the overdrive slightly through your amp.

There was a lovely fix posted on here a long time ago should really search for it.

[wampcat1]

I own an SD-1 and its got a lovely sound, I wouldnt want to make it into something TS sounding, I would just build my own if I wanted one so a +1 to whoever said it first.

Only one big flaw in the SD-1 I dont like and keep meaning to fix.  Is when the drive is up full and you bypass the pedal you can still hear the overdrive slightly through your amp.

There was a lovely fix posted on here a long time ago should really search for it.

[Papa_lazerous]

wampcat1 you are a lovely chap, consider that printed out and saved for when I finally get my workshop sorted (I moved and its a bloody mess)

[Melanhead]

Hey MelanHead....

i just checked out your band Mindzeye.. very cool..... Very Cool

Gee thanks! ... It's a work in progress and I'm having a ton of fun shredding again 

[AC30Dirty]

so, when let's say analogman, or keeley, or vodka mods or any other modder claiming they bring the SD-1 to TS808 specs do they replace everything the moro listed or is it just those two resistors an a cap or two?

[the_random_hero]

so, when let's say analogman, or keeley, or vodka mods or any other modder claiming they bring the SD-1 to TS808 specs do they replace everything the moro listed or is it just those two resistors an a cap or two?

Not 100% sure, but I say they'd just change those two resistors and caps. Keeley might be a good guy and damn, he makes some nice sounding pedals, but I love how he talks up his "very expensive triple throw double pole switches". If only the public knew...

[AC30Dirty]

well, after all this tweaking I must say my favorite and in my opinion the best mod for this pedal is Melenhead's SD-1Freakbox mod. way better than keeley's 5-star mod. The only thing I'm not completely settled on are the clipping diodes. I don't want that F*@#-Drive sound as I already have one. So, the experimentation continues......

[moro]

well, after all this tweaking I must say my favorite and in my opinion the best mod for this pedal is Melenhead's SD-1Freakbox mod.

What is the freakbox mod?

[the_random_hero]

well, after all this tweaking I must say my favorite and in my opinion the best mod for this pedal is Melenhead's SD-1Freakbox mod. way better than keeley's 5-star mod. The only thing I'm not completely settled on are the clipping diodes. I don't want that F*@#-Drive sound as I already have one. So, the experimentation continues......

There's certainly a lot you can try then. A few guys over at Ultimate Guitar (not sure if mentioning other forums is a no-no here, I can edit this out if it is) had a running project in the design books - basically a ROG Tube Reamer with two rotary switches to choose between different clipping diodes. You've got germs, signal diodes, power diodes, mosfets, LED's, etc. Make sure you let us know what you like the best 

[AC30Dirty]

Hey moro, if you have a SD-1 take the time to try BOTH of these mods. You won't be disapointed...

http://www.diystompboxes.com/smfforum/index.php?topic=37620.0

[moro]

Hey moro, if you have a SD-1 take the time to try BOTH of these mods. You won't be disapointed...

http://www.diystompboxes.com/smfforum/index.php?topic=37620.0

Ah cool, thanks!

I might have to get a bunch of SD-1 to mess around with. There are so many mods I want to try out.

[AC30Dirty]

Hey Melenhead, I was wondering if you could explain the purpose behind each component you changed on your Freak Box mod? Except for the clipping section. I was noticing in your mod you have alot of part substitutions that I've NEVER seen on any other modders info (Keeley, Indyguitarist, Analogman, T-Von.....)? How did you come to these conclusions, if you don't mind. Thanks

[Melanhead]

hmmm Cool! ... and thanks ... let's take a look ...

Okay ... I'm not much a a theory guy, more of a tweaker/listener but here goes:


1. Replace 4558DD RC4558P ... (similar op-amp to the 4558D, I just happen to like using the RC4558P)

2.  C1,C3 - .047 ( same value just better cap - this is subjective but the way i went about it was that if the signal goes through it put in the best cap I had on hand, I don't think it's night and day and you can skip this step,  with C1 being more crucial)

.....   I now change C3 to .22uf and R6 to 1.8k for a fatter tone.

3.  C2/R4 - from the TS circuit.

C7,C10 - 1uf (these are polarized caps, many have argued that they should be not used in the signal path for various reasons, although I'm not sold on either using or not using them I replace them anyways ... again same value, better cap, most modders do this.)

4.  C4 - .22uF/ R7 1K is also right from the TS circuit.

5.  Remove C6 ... it's filter in the second op-amp stage ... many remove it to allow more highs to pass through ... it's a subtle change, but many subtle changes add up ...

6.  C8 - .1uf again, right from the TS circuit. Increases bottom end response slightly.


7   R17 - 10K from a TS.

8.  R9 - 1K ( I now use a 4.7k resistor here ... it makes the tone control a bit more usuable. 1K is the value in a tubescreamer. )

9.  R16 - 100 ohm. This is TS

10. R2 - 620k increases the input impedance slightly (Keeley does this I believe)

11. D4 - 1n4001 and 1N34 series
12. D5 - 1N4001
13. D6 - 1N4001 and 1N34 series

This mod was in the early stages of my learning, basiaccly trial and error ...

My new freakbox mod is much more involved, includes true-bypass and a "fat" switch and a few other tweaks not listed here ....

[Melanhead]

well, after all this tweaking I must say my favorite and in my opinion the best mod for this pedal is Melenhead's SD-1Freakbox mod. way better than keeley's 5-star mod. The only thing I'm not completely settled on are the clipping diodes. I don't want that F*@#-Drive sound as I already have one. So, the experimentation continues......

try replacing just D5 with a 1N4001 ...

[hendrix2489]

***** SD-1 5-Star Ge Mod ****
Keeley Custom Shop designed this mod to enhance the tone and functionality of the SD-1

Board Number    New part        Old part            Reason                              Where to get the part   

C10 --> Metal Stack Film 1uF,                     remove electrolytic,              increased fidelity, digikey

C7--> Metal Stack Film 1uF,                       remove electrolytic,                increased fidelity, digikey

R6 --> 2.4k ohm metal film,         4.7k,        increased distortion,                             digikey

C3--> 0.1uf metal stack film,      0.047uf,    fidelity and bass response,                    digikey

C2--> 0.1uf metal stack film       , 0.018      fidelity and bass response,                    digikey

R2--> 620k ohm metal film,       470k ohm, increased input impedance, better bypass, digikey

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

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 the, 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 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.

This pedal is a key element to many heavy rocker's tone. It's like the TS9 with more transparency and more edge. If you are looking for something in the Tube Screamer vein, but with a little more hair on it, not as much midrange push, this is it!

Now with Two TI RC455P IC Chips, it promises to deliver HUGE TONE!!!!!!!!!



hope this helps

[frokost]

The SD-1 was the pedal that got me in to this thing about a year ago, so I guess it's appropriate that my first post is about it too. I started with modding the heck out of it, because I simply wasn't happy with the sound. It was too tame. In the process I lifted a lot of pads, broke all the wires and in general made a total mess out of it 

Still, it's the only overdrive I have, and I need one. It still didn't do what I wanted though, with a lot of mods. Then, one day I decided to use the enclosure for a Nyquist Aliaser (with true bypass - no problem adding a 3PDT in a Boss enclosure), and I was without an overdrive. So I decided to to what the title of this tread says - convert a SD-1 to TS808 the real way. So I stripped away the parts from the switching section and used the pads and traces to replace the bits that I had damaged on the PCB a year ago 

I followed both schematics and swapped out the SD-1 stuff for 808 values - keeping some of them, like the 1M drive pot. Now I have a really nice overdrive. It sounds better, more aggressive, and MUCH LOUDER than the pedal that originally was populated on this PCB.

It looks a bit messy, but compared to what the SD-1 looked like after my newbie modding skills....

[dan5150]

This is a great thread!

I just grabbed a new SD-1 off of ebay just to mod because it seems like this pedal is a great platform for many mods/expereiments.

Hendrix2489 - Thanks for sharing the specs for the Keeley mod! I did his SEM to my DS-1 and it sounds much better than stock!

I have ready that in Keeley now does stack the op amps in his SD-1 5 star mods, and you mention it a bit in your post. In order to DIY the 5 star GE mod, are you suggesting to swap the components you list as well as simply soldering a couple of RC4558P chips on top of each other?

-Dan-