Wampler mod book boss sd-1

[TimWaldvogel]

Thursday or Friday I'm looking to modify my Boss sd-1. I have the Wampler mod book but idk which modification to choose. Im looking to make it have a more amp-like response. Kinda like a visual sound open road. Idk which mod to choose. I do like the sound of an OD-1 so maybe I can scrape by with minimum modification. I would love to hear to suggestions or testimonials from personal experience

[flintstoned]

+1 for the fooldrive. All of them are good, but the fulltone was the most improved, IMO.

[TimWaldvogel]

What do you think the repercussions would be if I did the full fulldrive modification but left out c6 instead of changing it with a cap?

[newfish]

From memory, if you remove C6, this gives some extra 'fatness' to the sound.

I did this to a couple of SD-1s a while ago - and it did exactly what it was supposed to.

This table may be of some use to you...

http://www.indyguitarist.com/mods_new/sd1-mods-206.pdf

Cheers!  Happy modding!

[TimWaldvogel]

Thanks newfish. My book had these mods in it already. My biggest problem is idk what any other of his mods sound like. I know I really want an amp-like overdrive. Maybe the fulltone is the key. But idk. The fulltone mod is the only one of his mods I could find a sample of online.
I was hopingaybe someone else had tried one of his mods and could steer me towards one of those mods

[Mark Hammer]

You need to have a clearer idea of what you mean by "amp-like distortion".  Until that gets translated into identifiable parameters, it becomes tricky to figure out what needs doing.

But here is a different suggestion in the meantime.  DON'T CHANGE THE DIODES.  Why not?  It is a frequent practice to "soften" the clipping provided by diodes by inserting a resistance in series with them.  Look at the Boss BF-2 flanger and you'll see that strategy in use in the op-amp stage just before the BBD.  That stage combnes the input signal and recirculated signal to feed the BBD.  You don't want that summed signal to be too large an amplitude for the BBD, but at the same time you don't want hard clipping either.  So, Boss stuck a 4k7 resistor in series with a diode pair to provide "soft limiting" (soft clipping, actually).

So, get yourself a 5-10k pot (taper is moot), and wire it up between the diodes and their return point at pin 6 of the clipping stage.  At zero ohms, it will behave as stock.  As the series resistance is increased, it will behave in what feels like a slightly more "dynamic" fashion, with more output.  This not unlike what happens when you change the diode type (Ge to Si to LED), or diode configuration (1+1 vs 2+1 vs 2+2, etc), except that instead of being in discrete steps, it is continuous.

You will note there is no feedback cap for treble-taming in the clipping stage.  All the toneshaping is done by the R7/C4 pair and the subsequent op-amp stage, with the C6/R9 pair rolling off around 1.6khz and R7/C4 rolling off around 884hz.  Personally, I am partial to rolling off  top end either at or before a clipping stage, so that less of the ugly harmonics is generated in the first place.  You will note that the SD-1 omits the functional equivalent of the 51pf feedback cap that the TS-9 uses in the clipping stage.  If you stick in a feedback cap, you can probably drop C6, either in value or altogether, for what starts to move towards a smoother and potentially more "amp-like" (depending on your definition) sound.

So, I'll suggest the usual bass improvement changes Brian has already outlined, and suggest you insert the variable resistance for clipping "softness" and the relocation of treble-taming from after the clipping stage to the clipping stage itself.  Given the value of the gain pot on the SD-1 (1M), a 39pf cap stradding the pot and 33k resistor oughta do it.  That will let you reduce C6 to 4700pf or thereabouts.

[TimWaldvogel]

Thanks MARK !

By amp-like I guess what I mean is

It has nice tonal characteristics
It is very dynamic. I am looking to have something that will be aggressive when picked hard and have nice sustain, but be soft and lightly driven when played soft. And clean up when I roll back the volume.

Probably asking too much Outta this pedal. I just want something that has a nice smooth-dynamic feel

[pinkjimiphoton]

in my opinion, the sd1 is close enough to my jcm800 that 90% of my musician friends can't tell the diff when they hear it.

all i did was change r5 (33k) to 4.7k for a better cleanup if i turn my guitar down. hope that helps. try different values there, 10k is pretty good too.

[TimWaldvogel]

Yea I'll definitely cut out c6 but idk about input caps or output, I have made a definitive decision that I like the feel of LED CLIPPING the best. All the mods I've listened to I like that best