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Wiring of Pi 3 & Amp2 & 7" touchscreen.

martin3

November 03, 2017 12:07

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Currently I use an Amp+. This means I have to use a separate power supply for the display. This does not work very reliably, I usually need 2-3 reboots before I finally get the display recognized.

Therefore the new Amp2 intrigues me: Only one power supply needed!

How do I wire up this combination? The official recommendation from the display is to power the Display via its USB connector, and use a patch cable from the display to the 5V / Ground pins to power the Pi.

Obviously this will not work, so how do I power the display once the Amp2 is (physically) using up all of the pins?

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14 comments

• 0
  
  HiFiBerry team November 03, 2017 12:24

  Hi,

  you can access the 5V and GND pins on the Amp2.

  Best regards,
  Daniel

• 0
  
  martin3 November 08, 2017 18:39

  Hello, the stacking header pins of the Amp 2 are too short. I could not find a single jumper cable that would make contact. This includes the jumper cable that comes with the 7 inch display itself.

  The screw terminal seems to be for inputting voltage, so I can't use this one either.

  Am I overlooking something?

• 0
  
  HiFiBerry team November 08, 2017 18:44

  On the screw terminal, you will have the full external power supply, not 5V. Connecting the display there will kill your display. You should look for jumper cables that are really tight - many aren't. Alternatively you can solder the cables.

  Best regards,
  Daniel

• 0
  
  martin3 November 08, 2017 18:49

  Thanks for your quick reply!

  The jumpers are too short, not too loose. Any terminals that I find (such as the one on the Raspberry Pi) are about 5.5 mm long. The ones on the Amp 2 are less than 4mm. So the pin doesn't go up to the part of the jumper that "grips" it.

• 0
  
  martin3 November 08, 2017 19:38

  In the end I found a jumper that worked. My display now turns on reliably and the Raspberry recognizes it on every boot. Great!

• 0
  
  Benjamin Allen December 04, 2017 03:44

  @Hifiberry Team

  In this post, you seem to recommend a separate power supply for the display, whereas in the above, you appear to suggest that jumpers from the Amp2 pins will power the display just fine. Is that a difference between Amp+ and Amp2, or am I missing something?

• 0
  
  HiFiBerry team December 04, 2017 11:15

  Hi,
  
  the Amp2 can provide more power to additional components than the older Amp+.

  Best regards,
  Daniel

• 1
  
  Transporter December 04, 2017 14:43

  @ Benjamin Allen

  The AMP2 is designed differently from the Amp+. Both provide similar function IE have the same general purpose of providing stereo amplifier output for passive speakers, but the AMP2 has more available current for accessories when matched with the proper power supply. This being the case, there is enough current available on the GPIO Header pins 2 & 6 to power the 5VDC Official RPi display (Note Pin 2 is positive and pin 6 in GND). I am running the 7 inch display with RPi3 and AMP2 using a 19VDC 3.75 amp brick power supply with PiCorePlayer as my OS. Basically I have a setup that mimics a 7 inch Squeezebox Touch but with 30 Watts out! It was great of HiFiBerry to address users needs of those wishing to use the Official 7 inch display when they produced the new AMP2.

  The reliable way to power the display with the Amp+ is by using an external 5 VDC supply to power the display or if one wants to use only a single power supply, then a 5 VDC 1 Amp voltage regulator has to be added to power the display. There are other posts that discuss how to add the regulator when using the Official 7 inch display with the Amp+. 

• 0
  
  Benjamin Allen December 04, 2017 16:21

  I have (on order) the Amp2, so it sounds like I'm fine. I'm wondering whether it's possible to add an on/off power button for the whole device with your setup?

• 0
  
  Transporter December 04, 2017 17:45

  Since I have built mine to mimic a Squeezebox, it needs to always at least be in stand-by so I can control/access it via LMS or my iPhone. So when it is not streaming and powering speakers, the display shows a clock and the RPi is just idling using hardly any power. All my Squeezeboxes and my media server are always on or at least in stand-by.

  Having stated all that, when I need to turn it off I pull the line side plug out of the Brick so that is basically my switch. If you wish to have a physical switch, I would unplug the line side lead from the wall and brick then cut-in a Leviton Appliance switch: 

  https://www.homedepot.com/p/Leviton-3-Amp-Appliance-Cord-Switch-White-R52-05410-00W/100201339

  The AC line input side of most brick power supplies used with an AMP2 don't exceed 2 Amps so this switched rated at 3 Amps is perfect. Additionally if ones brick power supply isn't the detachable two lead type (separate AC line cord and DC output cord), then unplug the brick from the Wall and AMP2 then cut-in the switch on the wall side of the brick's AC power cord. Now your project has an actual power switch!

  Due to the thin plastic of the SmartiCase and even their Hat Covers, I would not attempt to break the DC input side with a switch on the case. Guys building their projects into aluminum cases can easily and safely add a switch on the project. The project I built using an aluminum case and has an actual toroidal power supply with linear supplies for each voltage has a nice switched & fused IEC socket:

   

  https://www.amazon.com/URBEST-Socket-Switch-Rocker-Connector/dp/B00NM0M8W8/ref=sr_1_2?s=electronics&ie=UTF8&qid=1512409085&sr=1-2&keywords=inlet+male+power+socket+with+fuse+switch

  Enjoy the fun of building projects! Between the RPi and HiFiBerry Hats, one can't really go wrong as long as one follows the instructions and the project fits the purpose one is looking to use it for.

   

• 0
  
  Antonio Alemanno June 12, 2018 09:49

  Hi guys, sorry if i open again this topic, but else i needed to open another one similar.
  
  So, if i want add the display with raspi 3 and hifi amp 2 we need a power supply of 18v, right? but if i want add an external hdd (something like this https://www.amazon.it/Seagate-ST1000DM010-HDD-Sata-Grigio/dp/B01LY65EVG/ref=sr_1_1?ie=UTF8&qid=1528796024&sr=8-1&keywords=hdd+1t ), always with display, what power supply is good?!

   

  Edited by Antonio Alemanno June 12, 2018 09:51
• 0
  
  HiFiBerry team June 12, 2018 09:58

  The HD you have linked is an internal HDD: Many external HDDs will require an additional power supply.

  Some small 2.5" HDDs might work without one. 

  However, in general we recommend to use a Network attached Storage (NAS) instead of an USB disk as this configuration usually is more stable than USB hard disks directly connected to the Raspberry Pi.

  Best regards,
  Daniel

• 0
  
  Antonio Alemanno June 12, 2018 10:50

  Ok! 
  I know about the nas. My system is build with the nas, but when i want try a solution for the buffering when i use DSD files cause sometimes the song jump during the play. So i wanted an alternative

• 0
  
  Grover June 12, 2018 15:52

  Antonio, an alternative I've used for various reasons, if your router supports usb attached storage.