2 Replies Latest reply on Dec 23, 2017 5:14 AM by richardbeattie

    External 5v supply  instructions missing in user manual?




      I am making the assumption that one can power the audio card AND the Pi from the Aux 5V jack, thus avoiding the need for TWO power supplies.


      Just tried to use the Wolfson audio card with external 5V supply (5v Aux), so I can try the integrated speaker amplifiers.


      It will not work  without adding a link or 0 ohm resistor  R44, located by the side of the 5v jack socket. without this link, the aux 5v does NOT feed the internal 3.3 and 1.8 v regs.


      (see schematic diagrams.....  R44 is marked as DNP  do not populate, )


      The  user  manual states that one has to add terminations for the speaker cables and also


       It is necessary to supply auxiliary power to the Audio Card in order to drive
      external loudspeakers. An external power supply with output voltage of 5V,
      current delivery capability of 2,000mA, a centre positive power plug of internal
      diameter 2.1mm, and external diameter 5.5mm.


      But there is nothing about  inserting 0 ohm or link in R44




      Also, adding a link to R44 position is not for the inexperienced solderer! It's a 0603  size component.






      Message was edited by: Patrick Keane

        • Re: External 5v supply  instructions missing in user manual?



          Re-reading my last post I realised I had not fully stated the result  of connecting R44 and the  5v Aux

          So,,,,, I made a solder bridge on the Audio card at R44 position,  couldn't find a 0 ohm  SMD in my parts box.


          Stuck a 5v jack in the Audio card socket, with NO other PI connected power supply.


          It all works well, Pi  boots and  ausio works great,  i.e. running MPD and playing flacs onto line out.


          I have not tried  the loudspeaker outputs yet, I have to find a pair of small speakers in my junk box. I have a pair of Warfdale bookshelf speakers to hand  but they are marked 75W, I don't think a 1.4 W o/p will drive them very well!