Powering an Eden Mic Pre System

[Rochey]

This question just came in via PM, I thought I'd share the response.

Hey there Rochey,

I have (another) question pertaining to the eden mic pre, specifically for a setup of (2) eden pres, (2) front ends for the pres, (2) 3-button controllers and the uber PSU boards.  I realize that the uber power supply has pinouts for the + and - voltage for the pres, and it also has pinouts for the phantom power.  My question is about powering the (2) front ends and (2) 3-button controllers.  I was thinking that I would use a 9v battery to power the 3-button controllers by hooking one battery up to each 3-button controller board directly.  Then I realized that the front end mic pre boards need power too.  Does this mean I will need more batteries?  Or is there some way to run off of a single power supply to power these things.  Just wondering how that all connects.  Thanks so much Rochey!  Like I said last time, I'm learning so much and that's worth this whole process in itself!  Hope your holiday season is going smooth, talk to you soon!

The power rails you are refering to are all deemed "digital rails". In other words, anything that is driving digital circuitry, or any quickly changing currents (such as a relay switching). I like to use a separate power supply for these boards with grounds only being shared back at the power input.

Lets discuss the power requirements for each of these boards.

Mic Pre Front End (http://expataudio.myshopify.com/collections/mic-pres/products/mic-pre-frontend)

The digital power supply voltage for this board is set by the switching voltage of the relays you buy. The Omron G6K-2P relays that are used come in both 5V and 12V flavors. In my original design, I used 12V versions of the relays, but if I was building a new system today, I'd use 5V versions of the relays. That would allow me to use a small 5V USB charger as its power supply.

3 Button Controller & IC(http://expataudio.myshopify.com/collections/mic-pres/products/3-button-controller-ic)

The microcontroller and the led's on this board are designed to run from a 3.3v supply. However, the LP2950-33 chip thats used on the board is a regulator that is designed to bring the power down from any higher voltage (up to about 15V I think) down to 3.3V. That means you can connect it to the same digital power supply as the one used for the mic front end.


Recommendation

- Keep your analog and digital rails separate, with the respective GND's only being connected together at the IEC connector.
- Use a high-current (2A) 5V USB power supply inside your case. they are easy to source, easy to hook up. (amazon example http://www.amazon.com/Super-Power-Supply%C2%AE-2700HG-B-GPUSW0512000CD3S/dp/B00BW9JY0U/ref=sr_1_4?s=electronics&ie=UTF8&qid=1386781161&sr=1-4&keywords=2A+5V+supply)
- Use veroboard/stripboard to create power supply distribution boards. (ebay http://www.ebay.com/itm/Phenolic-StripBoard-2-x5-50-127mm-1000Hole-Prototype-PCB-Veroboard-/151007365387?pt=LH_DefaultDomain_2&hash=item2328bd890b)


Good luck, let me know how you get on!