Nord Modular DIY DSP Expansion...is there a secret?

Check Mate

Hi there, I have a very specific question and I hope someone might have an idea or put me on the right track.
Even though it is not exactly Nord Lead 2 specific it has something to do with the Clavia Nord Modular G1 which should have the same DSPs.
The thing is the following: I was working on remaking the DSP expansion board for the G1 based on schematics posted on a facebook group. The expansinon doubles the voice count per slot. The schematics seem to be legit and I was able to make a PCB and aquire 4 DSPs. The only things that are on the expansion board are 4 DSP Chips (56303PV80) and a Miltiplexer plus the header that connects to the main board of the G1.
After everything was finished I put the Expansion card in my G1 and it was recognized as "Expanded" on startup. However it does not work since I only have 1 Voice and only slot 1 is working. After removing my DIY expansion everything is back to normal.
My question is: Is there any kind of "flag" that could be set on the DSP itself for the G1 to register and to recognize as "Clavia" specific? Could Clavia have somehow "Preprogrammed" the DSPs in a way to prevent cloning?
I know that Encore electronics made them new (I bought one for my G2 which I no longer have). I wrote an E-mail but never got any answer. I wonder whether they had official permission from Clavia and access to all the documents or if they kust made them themselves.
Any hint would be appreciated. Thanks!

dean · Joined: Jun 06, 2013 Posts: 8 Location: Berlin

Good job on getting that far regardless!

From my understanding it should be straight forward as there is no microcontroller to initiate a handshake - I'm sure someone more experience can answer this, this place seems a bit dead however. I see you're in Germany. If you're in Berlin, you're welcome to look my actual expansion board to troubleshoot.

Check Mate · Posted: Sun Mar 22, 2026 5:54 am Post subject:

Hi Dean,

Thanks for the offer! I'm located near Braunschweig which is about 2h away by car.
Unfortunately I never had an OG to cross check but the schematics seem legit and I triple checked for mistakes.
Someone else tried to make some as well and ran into the same mistake so I suspected the DSPs where somehow preprogrammed or something.