wwoland
New member
Due to the problems with my VD boards, I also dug deeper into their schematic. The VD actually works as a "digitally controlled side chain", using an ADC after the ssm2110 analog RMS detector.
I think there may be 2 separate tasks: create a replacement board to (possibly) create more modern/feature-rich side chain filtering, and second - make it possible to control the old classic VD boards from modern OS/DAWs etc.
The first task looks like it could be solved with more modern microcontrollers, but then you either have to leave the analog RMS calculation (ad737?) and then use the MC's (some modern stm32g?) built-in DAC/ADC (but without the ability to add filtering), or move the RMS calculation to a digital environment and use external ADCs via the I2S bus
or maybe special DSP like the ADAU1701 (though it's not entirely clear how to get a DC control out of it plus you still need another MC to control it). Digital noise is again an issue to keep in mind, and none of this seems to be so simple.
For the second task, things look much simpler. I think the easiest way is to connect to the VD chain - I plan to connect an Arduino type board there to be able to send data to the serial line and control the I/O line to select the target processor. The only big part here is to reverse engineer protocol of communication with the processor
I think there may be 2 separate tasks: create a replacement board to (possibly) create more modern/feature-rich side chain filtering, and second - make it possible to control the old classic VD boards from modern OS/DAWs etc.
The first task looks like it could be solved with more modern microcontrollers, but then you either have to leave the analog RMS calculation (ad737?) and then use the MC's (some modern stm32g?) built-in DAC/ADC (but without the ability to add filtering), or move the RMS calculation to a digital environment and use external ADCs via the I2S bus
or maybe special DSP like the ADAU1701 (though it's not entirely clear how to get a DC control out of it plus you still need another MC to control it). Digital noise is again an issue to keep in mind, and none of this seems to be so simple.
For the second task, things look much simpler. I think the easiest way is to connect to the VD chain - I plan to connect an Arduino type board there to be able to send data to the serial line and control the I/O line to select the target processor. The only big part here is to reverse engineer protocol of communication with the processor
