Rockman X100 or Sustainor Circuit…

Caldo71

Caldo71

Active member
Reposting from the older, now-archived wishlist…

Rockman X100 in pedal format?

Would be an interesting project. Originals are getting pretty expensive.
forum.pedalpcb.com forum.pedalpcb.com
Where it seemed for a while there was some forward movement (a “Goat” was purchased) and then things seemed to sadly fizzle.

Also really want to re-iterate that although there is always constant hype around that hilariously cheezy trademark Rockman distortion sound, it’s the “CLEAN 1” tone that truly shines and remains über useable to this day. Would be a shame to leave that part of the circuit forgotten.
 
Upvote 5
I'm waiting on that other Rockman-inspired pedal right now. While mine sounds great, it's not very versatile since it's directly based off the original circuit and has no gain or tone controls.
 
Ok, so looking at the schematic, the only gotcha I can see is the distortion/clean switch. It uses a 4PDP switch which isn't too common. Could switch to a different layout...maybe a 4PDT? But that would mean reworking the circuit to accommodate a completely different switch layout. Not impossible...but the circuit is a bit funky so updating might require a bit of rerouting of things.
 
The X100 used a clever technique. The switch was a slide switch with a small lever that moved another internal slide switch when slid to one extreme. Scholz is a brilliant designer.

You can see it on the right in this picture.
1657212789307.png
 
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Bricksnbeatles said:
What kind of switch was it originally? You said 4pdp but I’ve never heard of such a thing that isn’t xPyT
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Yeah, it's a really odd switch but totally makes sense when you look at the schematic. Basically, it's two rows of 5. So, if you look at the rows as pins 1-5 on one side and 6-10 on the other, when the switch is in the top position, pins 1 & 2 are linked and 6 & 7 are linked. Go to position 2 and then its 2 & 3 and 7 & 8 and so on. The idea is that parts of the circuit can be linked together on either side.

With this one, the idea is to switch between four different modes: two distorted and two clean. The Distortion and Edge parts share the same part of the circuit but switching to Edge removes one part of the circuit. Switching to either of the cleans removes the whole distortion part of the circuit altogether. This is what pins 1-5 are responsible for.

The other side manages what is going to the EQ stage. The EQ stage is divided into two parts with the distortion modes going to EQ 1 and cleans to EQ 2. Pins 6 - 10 manages all that.

So the goal is to see if the same thing can be done with a rotary switching, something like a 4P2T or the like. Pretty sure it can. Just need to think it though a bit. :D
 
jeffwhitfield said:
Yeah, it's a really odd switch but totally makes sense when you look at the schematic. Basically, it's two rows of 5. So, if you look at the rows as pins 1-5 on one side and 6-10 on the other, when the switch is in the top position, pins 1 & 2 are linked and 6 & 7 are linked. Go to position 2 and then its 2 & 3 and 7 & 8 and so on. The idea is that parts of the circuit can be linked together on either side.

With this one, the idea is to switch between four different modes: two distorted and two clean. The Distortion and Edge parts share the same part of the circuit but switching to Edge removes one part of the circuit. Switching to either of the cleans removes the whole distortion part of the circuit altogether. This is what pins 1-5 are responsible for.

The other side manages what is going to the EQ stage. The EQ stage is divided into two parts with the distortion modes going to EQ 1 and cleans to EQ 2. Pins 6 - 10 manages all that.

So the goal is to see if the same thing can be done with a rotary switching, something like a 4P2T or the like. Pretty sure it can. Just need to think it though a bit. :D
Click to expand...
Can you share the schematic you looked at? That sounds like it’s more like (but not the same as) a 2p4t
 
Ah yeah, that’s just a dp4t. There are types with a common lug and types without (such as a dp3t slide switch on a mustang), and this is the type without. You can get them as slide switches and occasionally as blade switches. Not sure I’ve ever seen a rotary switch without a common, but I’m sure they exist. Otherwise the functionality could easily be recreated with one dpdt and one 4pdt toggle switch
 
Actually, I figured out a better option. Instead of putting everything on one switch, break them out a little for more options. One switch for DIST/EDGE, another for CLEAN 1/CLEAN 2, and a stomp switch so you can go back and forth between distorted and clean.
 
Robert said:
I'm waiting on that other Rockman-inspired pedal right now. While mine sounds great, it's not very versatile since it's directly based off the original circuit and has no gain or tone controls.
Click to expand...

Something to think about for sure. There’s a few spots in the circuit I’d like to play with for some tone control. There’s one trimmer in the distortion circuit. Could be a gain pot.
 
Here's what I got so far. Now, the only thing I'm unsure about is the power requirements. It looks like the original ran at 6v? I don't see any reason why this circuit couldn't run higher than that. Surely 9v will still work. Gonna breadboard this and go from there.

Hmm...might need to migrate this convo to a different thread other than the Wishlist. :p
 

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jeffwhitfield said:
Here's what I got so far. Now, the only thing I'm unsure about is the power requirements. It looks like the original ran at 6v? I don't see any reason why this circuit couldn't run higher than that. Surely 9v will still work. Gonna breadboard this and go from there.

Hmm...might need to migrate this convo to a different thread other than the Wishlist. :p
Click to expand...
It's +/-6V, so either a charge pump and regulator or it could just be 12V with a voltage reference or if you're skipping the chorus section, sure it would sound fine at 9V and just the option to run at 12V if the user happened to have a supply.
 
jeffwhitfield said:
Something to think about for sure. There’s a few spots in the circuit I’d like to play with for some tone control. There’s one trimmer in the distortion circuit. Could be a gain pot.
Click to expand...
I can't enlarge the schematic but I think that trimmer is related to the input compressor. It looks like the distortion stage itself is the hard clipped LED portion, which could easily accommodate a gain pot, as for tone control, the two twin-t's could be made adjustable with a bit o-simulatin' but I think I'd look at adding something like an output tilt EQ.
 
jeffwhitfield said:
Actually, I figured out a better option. Instead of putting everything on one switch, break them out a little for more options. One switch for DIST/EDGE, another for CLEAN 1/CLEAN 2, and a stomp switch so you can go back and forth between distorted and clean.
Click to expand...

I won't say it is an improvement on the original, but I will say that it would take advantage of the different form factor for a pedal. Looking up Tom Scholz's patents quickly lets you see that his MIT engineering degree has been put to a lot of use.
 
Scruffie said:
It looks like the distortion stage itself is the hard clipped LED portion, which could easily accommodate a gain pot,
Click to expand...

It is. Oddly enough some versions use soft clipping in that same location. (or maybe it's the Sustainor or Distortion Generator?)

I built the distortion + EQ standalone and put a gain pot in there. I never investigated why, but it just sounded really off unless the pot was near dimed, defeating the whole purpose. The breakup crackled and just sounded broken.
 
For the MODE and FX switching, we used two stomps. Each employs a a 4-bit sequential switching (simple debounce and dual J-K flip-flop) circuit to drive a few CD4052 analog switches. The MODE switching requires two CD4052 analog switches and the FX switching suffices nicely with just one CD4052, but also allows for a "Dry" option.

It boots up in MODE: "DIST" & FX: Chorus". Each stomp can then cycle thru each of the next three options and starts over.

I also found that replacing that 10K input level trimmer with a B100K introduces a bit more volume and aids tremendously in achieving that "brown" sound. It also has some sway with the overall 'tone'.

IMO, a volume pot after a distortion section sounds/works better with soft-clipping as opposed to hard-clipping like used in the X100.
 
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