# Patching the Kurzweil K2500 OS using Ghidra



## rogierhofboer (Apr 24, 2022)

Software related, but there is a physical synth involved. I know it officially does not belong on this forum, but I know some people appreciate these kind of articles.









Patching an Embedded OS from 1996 with Ghidra


For reasons I won’t get into, I’ve been working on a tricky reverse engineering puzzle recently: how to patch the operating system of a 26-year-old synthesizer. To be specific, the Kurzweil K2500, a sample-based synthesizer released in 1996. As...




blog.petersobot.com


----------



## doctoremmet (Apr 24, 2022)

Great read Rogier - thanks for posting. As a long timer K2500 user this was intriguing for me.


----------



## ptram (Apr 24, 2022)

Very interesting reading indeed! But discovering that my K2500R is 26 years old makes me think at how old I am…

It's all but an outdated musical instrument. It still does things that I've not found in any modern virtual synth. And still sounds really great!

Paolo


----------



## artomatic (Apr 24, 2022)

Still have my rack and continue to use some patches not available on other platform - 
loaded to its whopping 48k of memory!


----------



## Nick Batzdorf (Apr 24, 2022)

I use a 2500X as my controller.

What is the goal of this hack? Does it improve the instrument or is it just an exercise?


----------



## jazzman7 (Apr 24, 2022)

Nick Batzdorf said:


> I use a 2500X as my controller.
> 
> What is the goal of this hack? Does it improve the instrument or is it just an exercise?


Same here:


----------



## IvanP (Apr 25, 2022)

2500 User here as well as controller...actually K2600

It's getting pretty worn-out btw...But I'm so much used to it now...Any similar hammered action and fader Controller alternatives ?


----------



## ptram (Apr 25, 2022)

IvanP said:


> It's getting pretty worn-out btw...But I'm so much used to it now...Any similar hammered action and fader Controller alternatives ?


Any Fatar-based controller should do. Including Fatar's own line (Studiologic). They have been constantly improved, so a modern one will be even better.

Paolo


----------



## EvilDragon (Apr 25, 2022)

K2000 (61): Fatar TP/9S, weighted
K2500 (76): Fatar TP/8Piano
K2500X (88): Fatar TP/10
K2600 (76): Fatar TP/8Piano
K2600X (88): Fatar TP/10MDF
K2661 (61): Fatar TP/9S, weighted



ptram said:


> They have been constantly improved, so a modern one will be even better.


Unless you get the ones made in Tunisia rather than Italy... they've actually become more inconsistent unfortunately.


----------



## IvanP (Apr 25, 2022)

ptram said:


> Any Fatar-based controller should do. Including Fatar's own line (Studiologic). They have been constantly improved, so a modern one will be even better.
> 
> Paolo


Thank you Paolo!


----------



## IvanP (Apr 25, 2022)

EvilDragon said:


> K2000 (61): Fatar TP/9S, weighted
> K2500 (76): Fatar TP/8Piano
> K2500X (88): Fatar TP/10
> K2600 (76): Fatar TP/8Piano
> ...


Thank you SO much!!


----------



## EvilDragon (Apr 25, 2022)

Do note that those are _older_ variants of Fatar actions. If they have the same model name today, it might not be exactly the same feel. In fact, it's very likely. I remember old 2500s were plagued by "lead weights falling off" issue, well now they aren't even allowed to use lead, etc.


----------



## Nick Batzdorf (Apr 25, 2022)

EvilDragon said:


> K2000 (61): Fatar TP/9S, weighted
> K2500 (76): Fatar TP/8Piano
> K2500X (88): Fatar TP/10
> K2600 (76): Fatar TP/8Piano
> ...



Someone on the Kurzweil mailing list said that the keybeds on the K2500X came in more than one version (although they could all be different manufacturing runs of Fatar TP/10, i.e. they could have fixed problems in later runs). It was in response to my question about how to fix the squidgy sounds a couple of keys make.

Or maybe it was about the thunk a couple of other keys make on release.


----------

