Externally Powering the Seed

Eurorack
1

I’m curious as to what’s the best way of powering the Seed when in a Eurorack system? Yesterday I had +12V DC going into a LM7805, then the output of that (5.05V DC) to the Vin of the Seed. I also had the GND of my PSU connected to the AGND of the Seed. Unfortunately, this fried the Seed completely. I am curious as to why?

  1. Is the proper way of powering it using Vin and DGND (instead of AGND)?
  2. Should I just have the 12VDC go straight into the Seed and bypass the 7805 completely?
  3. When using a potentiometer with the Seed ((1)GND, (2)GPIO, (3)3.3V), is it best to use AGND or DGND? 3v3 Analog or 3v3 Digital?

Thanks a ton to anyone who can help me out. I’ve ordered some more Seeds, but would like to more about properly powering it, in addition to using hardware (such as a potentiometer) with the Seeds power. Attached is a photo of my circuit layout in case anyone can spot anything else wrong with what I’m doing.

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123766970_2734500200200731_8284749306124490357_n1080×1920 753 KB

2

Hi @Reesepuffs, sorry to hear it blew your Seed up. DGND and AGND must be connected to each other outside of the Seed. They are meant to be the same signal, but having the connection be off the board itself results in better noise performance. This is fairly common among various ICs and SOMs.

I have done some fairly sketchy things and have rarely managed to permanently fry a Daisy Seed. Have you verified that even via USB the Daisy no longer boots up?

While I seem to recall accidentally doing and it not completely destroying the Seed, it likely depends on several factors since the floating GND could be “seen” by the circuit at a very different voltage than “0V”.

I prefer to step down a higher voltage to 5V or so. Using an LM7805 is totally fine for this. However, plugging 12V directly into VIN also works, but will result in a bit more heat generation, and therefore an increase in current consumption.

Hope that answers your questions!

1 Like
3

That’s okay, the Seed is something I want to continue working with in the future, so it was an excuse to purchase more! Interesting to find out about how the two GNDs must be connected, I didn’t know that! What baffles me is that the Seed seemed to work fine with DGND + Vin, but died a horrible death when I did AGND + Vin.

Yes unfortunately the Seed is dead. Upon connecting it to just USB power, the PWR light flickered for a bit, and faded away.

In case anyone’s curious, here are photos of my PSU’s output, in case anyone can spot anything strange (maybe my PSU is whack and my seed configuration is just fine).

Cheers,

Jim+ve voltage +ve wave -ve voltage -ve wave