FM-303 Mod
Make your PAIA FatMan sound like a TB-303.
By: AlphA

Quite a few years ago (early-mid nineties), I modified my PAIA FatMan to sound more like the classic Roland TB-303. For an example of what the modified FatMan sounded like, listen to Trigger.mp3. At 1:12 the FatMan enters the track and eventually takes the lead with a 303 style 16 step pattern loop. Here is an earlier test I had conducted before implementing the accents. I added a few small yet precise filter tweaks in order to brink out that drippy acidic sound.

The sequencing of the loop itself contributes to the 303 sound. At the time, I was using custom software which I had developed to control the FatMan along with much of my studio, on the fly. Details about the software are beyond the scope of this article. However, I do plan to make it available at bigmech.com. EDIT: And I did. Check it out here. With some work, this style of sequencing can be accomplished with most MIDI sequencers.

Once I acquired a real 303, I decided to tweak and add to the FM-303 mod. This was the beginnings of the FatMan AcidBox mod, which is a more extreme version of its Predecessor. The AcidBox not only emulates but enhances the subtle characteristics of the popular Roland TB-303 sound at the cost of authenticity. So, it is no longer considered a 303 clone. A test recording of the AcidBox can be heard here.

I have received many requests for my FatMan FM-303 mod schematics. Much of the work I did was the result of improvisation. Therefore, this modification was not well documented. So, I have decided to release excerpts from the holy notebook of doom. Some of the research may seem a bit redundant. Keep in mind, information on the TB-303 was less abundant back in the day.

Anyway, I hope this helps give all of the gearhead modders a head start toward getting the 303 sound out of their FatMan synth.

Notebook

Loose

Enhanced References

Images

 

-AlphA

 

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