WM8816 digital volume control (WM STAMP)

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
A couple of months ago I purchased boards and components from veteran (and wm8816s form Wolfson) and I have finally found the time to complete the assembly and test of a prototype.

I have started with the driver module. I only want the volume control and there are very few components to solder on the driver pcb as you can see on the picture (there are not many more for the relay selector, the board has been designed for possible extensions):
 

Attachments

  • drv1low.jpg
    drv1low.jpg
    64.9 KB · Views: 1,018
And now the whole thing. To be honest it did not work at first and it took me some time to find a bad solder on a smd resistor. Once corrected it worked fine.

I do not know about the sound. For the time being I am happy just looking at the trace on the 'scope.

Many thanks to Damian. I am very happy with the result. I now have to find the time to build the rest of the project (an 8 way attenuator)!

Cheers

Christian
 

Attachments

  • all low.jpg
    all low.jpg
    76.3 KB · Views: 1,035
veteran has published the costs somewhere on this thread. You should contact him on the email address on his unisonus.com site to have confirmation.

veteran sent me the PCBs, the pre-programmed Atmel controller (no, I do not think he will make the code public), the optocouplers, the smd resistors, the sockets, cable, everything except the wm8816s (he said a few days ago he can supply these too now), the opamps (your choice) and the traditional resistors and electrolytics.
 
You can drive several wm8816s from the same driver and cable. I am actually building an 8 channel volume control with 4 wmstamp boards all driven by the same controller.
However all wm8816s will always be at the same attenuation level.
If you want a fixed offset between some channels, it has to be done elsewhere.

There would actually be a possibility to separately address several wm8816s but it would require a modification in the controller programming. The board would also allow only 3 wm8816s to be driven, using the J1, 2,3 jumpers (in the present implementation, all jumpers on your wmstamps boards should be in the J1 position).

Christian
 
Tengsimon, I replayed your email.

For those who will assemble my deriver boards - there is no need to mount all the components.

1) There is no need for relay circuit - just solder two 0R resistors:

An externally hosted image should be here but it was not working when we last tested it.



2) Only JP3 is needed in the area of CON2 connector:

An externally hosted image should be here but it was not working when we last tested it.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.