[sdiy] DX7 hacking?

Adam Inglis 21pointy at tpg.com.au
Mon Jul 2 05:20:00 CEST 2012

On 01/07/2012, at 3:00 AM, Barry Klein wrote:

> When the DX7 came out I was one of those in awe.  When I compared it  
> to my
> simple modular I sort of just gave up on modulars and building and  
> just
> spent time playing.  Then I started buying analog synths in need of  
> repair,
> fixing them, playing them for awhile, and then sticking them in the  
> garage
> with the rest.  As analogs were not as well favored as digitals back  
> then,
> analogs needing repair were affordable - so it was a satisfying  
> pastime.
> Going through all this helped me learn a bit about synths that I  
> never would
> have been exposed to earlier - yet alone have the money to buy back  
> then.
> So anyway, as I progressed through this I occasionally went back to  
> that DX7
> and enjoyed its unique character but hearing it in most every patch  
> was
> audibly boring.  I didn't get into effects devices like Eventide or  
> the like
> until much later.  I always expected someone to hack the DX7 into  
> more of a
> monster.
> I never saw it happen.  Has anyone ever made any progress or  
> attempts? -
> something that gives it a sound character other than FM?  Is the  
> design too
> "purposed" for FM to alter?
> I'm sure I could just forget about it and realize that newer synths  
> probably
> have the FM as just one sound option.  I just don't have anything  
> that new.
> Barry

Back in the early 1990s Robin Whittle sold ROM chips for the original  
DX7 that turned it into a versatile midi master controller, with an  
adjustable keyboard split, midi panic button, and various assignable  
midi CC options.
This ROM mod also provided interesting voice options:-
•  one to three unison voices (at the expense of polyphony) with  
individually programmable detune amounts - truly speaker-shattering on  
some FM bass sounds,
•  a stretch tuning feature to emulate acoustic pianos,
•  full-range velocity sensitivity
•  new ranges for the Fixed Frequencies, 10 kHz and 0.36 Hz, allowing  
the bottom operator in an algorithm to act as an LFO for example,
•  programmable voice volume, and up to twice-normal operator output  
levels, which could cause a lot of distortion if you weren't careful.

Robin at that time could also provide hardware mods that improved the  
DAC and SNR, accomodating the higher operator output levels.
I bought the ROM, and the machine to this day is still my studios midi  
master keyboard (and occasional provider of monster bass patches - but  
I still hate programming via that 2 line LCD!!)

Adam Inglis

More information about the Synth-diy mailing list