Dimitree
Well-known member
- Joined
- Jul 26, 2011
- Messages
- 122
after having successfully built my first prototype of a multichannel ADC/DAC board with ADAT interface, the next step I want to take is to build a hybrid multichannel interface/console for recording, monitoring and mixing.
It will have 24 mono channels with pan and fader, going to a stereo summing bus.
Each channel will have a switch to select between the DAC output or the balanced line input. This input also goes to the ADC for recording.
After the selector, there is a switchable Insert point, and then the usual fader/aux/pan and summing bus (not shown here).
I also added a Direct Out after the Insert, so that if I need to record the processed signal after the Insert, I can tap the signal there.
Currently, the DAC is a PCM1794, the ADC is a PCM4222.
The ADAT is done with V1401 and V1402 ICs, and there is a pair of them for each 8 channels.
I tried to draw a better and simpler front end that the ones I used for the prototypes, following the suggestions here on the forum thanks to many of you that helped on my various projects.
Some values are not yet indicated, since I still haven't determined them (like the input/output filter network, and the adjustable gain I need for the input).
Some values probably need to be checked again, for example those responsible for the input/output levels around the ADC/DAC.
There is a spare op-amp section, I will probably use it for a simple switchable 100Hz HPF before the fader, or maybe a buffer/rectifier for a bar-graph level indicator.
This is a one-off project for my small and simple home studio.
If you are asking why I choose PCM4222 and PCM1794, the reason is that time ago I was gifted with a bunch of them, so why not use them?
Of course I don't expect to get the full SNR that those ADC/DAC can provide, I know it would be hard.
What do you think? Do you have suggestions/opinions/corrections?
I apologise for mistakes or inaccuracies, I'm trying to do my best with this and I still have a lot to learn (I'm a computer engineer and so I'm not an electronic expert at all).
schematic:
It will have 24 mono channels with pan and fader, going to a stereo summing bus.
Each channel will have a switch to select between the DAC output or the balanced line input. This input also goes to the ADC for recording.
After the selector, there is a switchable Insert point, and then the usual fader/aux/pan and summing bus (not shown here).
I also added a Direct Out after the Insert, so that if I need to record the processed signal after the Insert, I can tap the signal there.
Currently, the DAC is a PCM1794, the ADC is a PCM4222.
The ADAT is done with V1401 and V1402 ICs, and there is a pair of them for each 8 channels.
I tried to draw a better and simpler front end that the ones I used for the prototypes, following the suggestions here on the forum thanks to many of you that helped on my various projects.
Some values are not yet indicated, since I still haven't determined them (like the input/output filter network, and the adjustable gain I need for the input).
Some values probably need to be checked again, for example those responsible for the input/output levels around the ADC/DAC.
There is a spare op-amp section, I will probably use it for a simple switchable 100Hz HPF before the fader, or maybe a buffer/rectifier for a bar-graph level indicator.
This is a one-off project for my small and simple home studio.
If you are asking why I choose PCM4222 and PCM1794, the reason is that time ago I was gifted with a bunch of them, so why not use them?
Of course I don't expect to get the full SNR that those ADC/DAC can provide, I know it would be hard.
What do you think? Do you have suggestions/opinions/corrections?
I apologise for mistakes or inaccuracies, I'm trying to do my best with this and I still have a lot to learn (I'm a computer engineer and so I'm not an electronic expert at all).
schematic:
Last edited:
