Expat Audio EDEN Microphone Preamplifier

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e.oelberg said:
did anybody ever built a battery powered preamp with this ?

I've had many MANY customers email me about doing this. Every time I've asked for photographs etc, but I think folks are too busy recording once they are built.

Edens could easily be driven with two 9V batteries. Very easy to drive.

I'm also looking at a 5V USB power-bank to bipolar power supply to do these things too.


I looked at that part, but the issue is that it can only sink/source a fixed amount of current. (20mA)

I was looking at developing a heavily filtered SMPS that could generate ±18V that could be LDO'd if required.

The main benefit is being able to use those USB power packs on the move.

great. I think a simple portable solution as upgrade for one f those standard recorder like zoom, or tascam dr100.

I could design the box
I just bought one of this xiaomi power banks here in shanghai, and they are cheap and they made me think. did you ask your collegues about a possible psu for your boards plus 48Volt phantom power ?

Cases now available at www.collectivecases.com



It’s typically easier to find large value caps in polarized form. I like 47uF - it’s a nice mix of size and capacitance. Make sure they are at least ~65V caps.
Rochey said:
It’s typically easier to find large value caps in polarized form. I like 47uF - it’s a nice mix of size and capacitance. Make sure they are at least ~65V caps.

Thanks for the quick reply! Also, I don't have a board in front of me so is it easy to determine how to orient the cap for pos/neg?
You want the +’be of the caps in the holes on the left hand side (if you have inputs on the left to the outputs on the right).

Most folks i’ve Seen put those caps on their front end pcb, along with some matched low value resistors, just to limit the current if you don’t have slow starting phantom supplies.

I just picked up the handy 4 pack of the Eden Microphone Preamplifier and the 3 Button Controllers. I plan to get a Collective Cases 1U container and the rest of the Eden modules Mouser parts etc.  There is a meter module available which is intriguing but no place to put it on the prepared face plate.  I was wondering if anyone has tried to include a LED metering per channel either on the side of the gain knob similar to the WA-412 or over the 3 Button Controller like the Black Lion Audio B12A.  I think dropping the kind of money into this unit as I'm sure I will be doing it would be a huge disappointment to not have metering available, even if it was just 4 lead meters bunched together of the left or right side.

Anyone taken this one on.
Sure, I'll dig out my shoehorn and we'll figure out a spot for them.  I think it will add a nice touch; classy and pragmatic.

biggest challenge will be the front panels. We provided drawings etc to the Dan for the 3 button controller and mic pre, but you'll have to drill through the paint and metal yourself.

Drop me a note on facebook - look for Expat Audio on facebook. I can respond through there easily.