Anyone looked at Tech 21 (Sansamp)secret epoxy encased circut/chip?

[Om_Audio]

I am repairing my old Tech 21 Trademark 60 amp and have loved it for over a decade. It is supposedly all analog and does a great job at tube amp emulation. I noticed a black square on the PCB and on the backside I could see a grid of metal squares- obviously contacts for whatever is in the epoxy filed box. I am curious as to what it actually is- a custom IC?
I can post pics later.
C